build system and module refactoring + simple histogram scratch (#20)

* scratch adding histogram to image views

Histograms should come from some sort of histogram service. This is
currently just a POC.

* custom logger implementation w/o spdlog

* missing cmake file

* fix tests

* use operator<< over direct stream exposure

* rm print header

* add threading test + refactor towards interface libraries

omits the need for =target_include_directories= calls /everywhere/

* rm print header

* rm constexpr

* templated thread_pool

* fix doxyfile

* default enable doc building

* czi reader refactor

* rm erroneous include expression

* clang-format

* single lib include with PUBLIC visibility

* compile imgui stdlib

* clang format

* documentation update

centralize `LogLevelToString` to `ILog.hpp`

update docs and examples

.github/workflows/build-ubuntu.yml

@@ -0,0 +1,33 @@
+name: build-ubuntu
+
+on:
+  workflow_dispatch:
+  workflow_call:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        configuration: [Debug, Release]
+
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        submodules: recursive
+    - name: setup
+      run: |
+        sudo apt update
+        sudo apt -y install libopencv-dev libglfw3 libglfw3-dev libxkbcommon-dev libxinerama-dev libxcursor-dev libxi-dev doxygen graphviz
+
+    - name: Configure Ubuntu
+      run: cmake -B ${{github.workspace}}/build/gcc-${{ matrix.configuration }} -S . -DCMAKE_BUILD_TYPE=${{ matrix.configuration }}
+
+    - name: Build Ubuntu
+      run: cmake --build ${{github.workspace}}/build/gcc-${{ matrix.configuration }} --config ${{ matrix.configuration }} -- -j 10
+
+    - name: Test Ubuntu
+      run: |
+        cd ${{github.workspace}}/build/gcc-${{ matrix.configuration }}
+        ctest -C ${{ matrix.configuration }}
+

.github/workflows/build-windows.yml

@@ -0,0 +1,43 @@
+name: build-windows
+
+on:
+  workflow_dispatch:
+  workflow_call:
+
+jobs:
+  build:
+    runs-on: windows-latest
+    strategy:
+      matrix:
+        configuration: [Debug]
+
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        submodules: recursive
+
+    - name: Cacke vcpkg
+      uses: actions/cache@v3
+      with:
+        path: 'C:/vcpkg/installed'
+        key: vcpkg-x64-windows-${{ matrix.configuration }}
+        restore-keys: |
+          vcpkg-x64-windows-${{ matrix.configuration }}
+
+    - name: Install OpenCV vcpkg
+      run: |
+        vcpkg install opencv[core]:x64-windows-static
+
+    - name: Set PATH for vcpkg
+      run: echo "PATH=C:/vcpkg/installed/x64-windows/bin:${{ env.PATH }}" >> $GITHUB_ENV
+
+    - name: Configure Windows
+      run: cmake -B ${{github.workspace}}/build/msvc-${{ matrix.configuration }} -S . -DCMAKE_BUILD_TYPE=${{ matrix.configuration }} -DCMAKE_TOOLCHAIN_FILE=C:/vcpkg/scripts/buildsystems/vcpkg.cmake -DVCPKG_TARGET_TRIPLET=x64-windows-static
+
+    - name: Build Windows
+      run: cmake --build ${{github.workspace}}/build/msvc-${{ matrix.configuration }} --config ${{ matrix.configuration }} -j 10
+
+    - name: Test Windows
+      run: |
+        cd ${{github.workspace}}/build/msvc-${{ matrix.configuration }}
+        ctest -C ${{ matrix.configuration }}

.github/workflows/ci-workflow.yml

@@ -0,0 +1,25 @@
+name: CI Workflow
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+  workflow_dispatch:
+
+jobs:
+  build-ubuntu:
+    uses: ./.github/workflows/build-ubuntu.yml
+
+  build-windows:
+    uses: ./.github/workflows/build-windows.yml
+
+  generate-docs:
+    permissions:
+      id-token: write
+      pages: write
+    uses: ./.github/workflows/generate-docs.yml
+    if: github.ref == 'refs/heads/main'
+    needs:
+      - build-ubuntu
+      - build-windows

.github/workflows/generate-docs.yml

@@ -1,40 +1,33 @@
-name: C/C++ CI
+name: generate-docs
 
 on:
-  push:
-    branches: [ "main" ]
-  pull_request:
-    branches: [ "main" ]
   workflow_dispatch:
+  workflow_call:
 
 jobs:
   build:
     runs-on: ubuntu-latest
-
     steps:
     - uses: actions/checkout@v4
       with:
         submodules: recursive
+
     - name: setup
       run: |
         sudo apt update
-        sudo apt -y install libopencv-dev libglfw3 libglfw3-dev libxkbcommon-dev libxinerama-dev libxcursor-dev libxi-dev doxygen graphviz
-    - name: configure
-      run: cmake --preset gcc-debug
-    - name: build
-      run: cmake --build build --preset gcc-debug
-    - name: test
-      run: |
-        cd ${{github.workspace}}/build/gcc-debug
-        ctest -C Debug
+        sudo apt -y install doxygen graphviz
 
-    - name: Upload static files as artifact
+    - name: Generate Documentation
+      run: |
+        cmake -S . -B build -DPIXELARIUM_BUILD_DOCS_ONLY=ON
+        cmake --build build
+
+    - name: Upload Documentation Files as Artifacts
       id: deployment
       uses: actions/upload-pages-artifact@v3
       with:
-        path: ${{github.workspace}}/build/gcc-debug/doc/html
+        path: ${{github.workspace}}/build/doc/html
 
-  # Deployment job
   deploy:
     environment:
       name: github-pages

.github/workflows/mega-linter.yml

@@ -0,0 +1,204 @@
+# MegaLinter GitHub Action configuration file
+# More info at https://megalinter.io
+---
+name: MegaLinter
+
+# Trigger mega-linter at every push. Action will also be visible from
+# Pull Requests to main
+on:
+  # Comment this line to trigger action only on pull-requests
+  # (not recommended if you don't pay for GH Actions)
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+# Comment env block if you do not want to apply fixes
+env:
+  # Apply linter fixes configuration
+  #
+  # When active, APPLY_FIXES must also be defined as environment variable
+  # (in github/workflows/mega-linter.yml or other CI tool)
+  APPLY_FIXES: none
+
+  # Decide which event triggers application of fixes in a commit or a PR
+  # (pull_request, push, all)
+  APPLY_FIXES_EVENT: pull_request
+
+  # If APPLY_FIXES is used, defines if the fixes are directly committed (commit)
+  # or posted in a PR (pull_request)
+  APPLY_FIXES_MODE: commit
+
+concurrency:
+  group: ${{ github.ref }}-${{ github.workflow }}
+  cancel-in-progress: true
+
+jobs:
+  megalinter:
+    name: MegaLinter
+    runs-on: ubuntu-latest
+
+    # Give the default GITHUB_TOKEN write permission to commit and push, comment
+    # issues, and post new Pull Requests; remove the ones you do not need
+    permissions:
+      contents: write
+      issues: write
+      pull-requests: write
+
+    steps:
+      # Git Checkout
+      - name: Checkout Code
+        uses: actions/checkout@v5
+        with:
+          token: ${{ secrets.PAT || secrets.GITHUB_TOKEN }}
+
+          # If you use VALIDATE_ALL_CODEBASE = true, you can remove this line to
+          # improve performance
+          fetch-depth: 0
+
+      # MegaLinter
+      - name: MegaLinter
+
+        # You can override MegaLinter flavor used to have faster performances
+        # More info at https://megalinter.io/latest/flavors/
+        uses: oxsecurity/megalinter/flavors/c_cpp@v9.1.0
+
+        id: ml
+
+        # All available variables are described in documentation
+        # https://megalinter.io/latest/config-file/
+        env:
+          # Validates all source when push on main, else just the git diff with
+          # main. Override with true if you always want to lint all sources
+          #
+          # To validate the entire codebase, set to:
+          # VALIDATE_ALL_CODEBASE: true
+          #
+          # To validate only diff with main, set to:
+          # VALIDATE_ALL_CODEBASE: >-
+          #   ${{
+          #     github.event_name == 'push' &&
+          #     github.ref == 'refs/heads/main'
+          #   }}
+          VALIDATE_ALL_CODEBASE: true
+
+          # Disable LLM Advisor for bot PRs (dependabot, renovate, etc.)
+          LLM_ADVISOR_ENABLED: >-
+            ${{
+              github.event_name != 'pull_request' ||
+              (github.event.pull_request.user.login != 'dependabot[bot]' &&
+               github.event.pull_request.user.login != 'renovate[bot]' &&
+               github.event.pull_request.user.login != 'github-actions[bot]' &&
+               !startsWith(github.event.pull_request.user.login, 'dependabot') &&
+               !startsWith(github.event.pull_request.user.login, 'renovate'))
+            }}
+
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+          # Uncomment to use ApiReporter (Grafana)
+          # API_REPORTER: true
+          # API_REPORTER_URL: ${{ secrets.API_REPORTER_URL }}
+          # API_REPORTER_BASIC_AUTH_USERNAME: ${{ secrets.API_REPORTER_BASIC_AUTH_USERNAME }}
+          # API_REPORTER_BASIC_AUTH_PASSWORD: ${{ secrets.API_REPORTER_BASIC_AUTH_PASSWORD }}
+          # API_REPORTER_METRICS_URL: ${{ secrets.API_REPORTER_METRICS_URL }}
+          # API_REPORTER_METRICS_BASIC_AUTH_USERNAME: ${{ secrets.API_REPORTER_METRICS_BASIC_AUTH_USERNAME }}
+          # API_REPORTER_METRICS_BASIC_AUTH_PASSWORD: ${{ secrets.API_REPORTER_METRICS_BASIC_AUTH_PASSWORD }}
+          # API_REPORTER_DEBUG: false
+
+          # ADD YOUR CUSTOM ENV VARIABLES HERE TO OVERRIDE VALUES OF
+          # .mega-linter.yml AT THE ROOT OF YOUR REPOSITORY
+
+      # Upload MegaLinter artifacts
+      - name: Archive production artifacts
+        uses: actions/upload-artifact@v4
+        if: success() || failure()
+        with:
+          name: MegaLinter reports
+          include-hidden-files: "true"
+          path: |
+            megalinter-reports
+            mega-linter.log
+
+      # Create pull request if applicable
+      # (for now works only on PR from same repository, not from forks)
+      - name: Create Pull Request with applied fixes
+        uses: peter-evans/create-pull-request@v7
+        id: cpr
+        if: >-
+          steps.ml.outputs.has_updated_sources == 1 &&
+          (
+            env.APPLY_FIXES_EVENT == 'all' ||
+            env.APPLY_FIXES_EVENT == github.event_name
+          ) &&
+          env.APPLY_FIXES_MODE == 'pull_request' &&
+          (
+            github.event_name == 'push' ||
+            github.event.pull_request.head.repo.full_name == github.repository
+          ) &&
+          !contains(github.event.head_commit.message, 'skip fix')
+        with:
+          token: ${{ secrets.PAT || secrets.GITHUB_TOKEN }}
+          commit-message: "[MegaLinter] Apply linters automatic fixes"
+          title: "[MegaLinter] Apply linters automatic fixes"
+          labels: bot
+
+      - name: Create PR output
+        if: >-
+          steps.ml.outputs.has_updated_sources == 1 &&
+          (
+            env.APPLY_FIXES_EVENT == 'all' ||
+            env.APPLY_FIXES_EVENT == github.event_name
+          ) &&
+          env.APPLY_FIXES_MODE == 'pull_request' &&
+          (
+            github.event_name == 'push' ||
+            github.event.pull_request.head.repo.full_name == github.repository
+          ) &&
+          !contains(github.event.head_commit.message, 'skip fix')
+        run: |
+          echo "PR Number - ${{ steps.cpr.outputs.pull-request-number }}"
+          echo "PR URL - ${{ steps.cpr.outputs.pull-request-url }}"
+
+      # Push new commit if applicable
+      # (for now works only on PR from same repository, not from forks)
+      - name: Prepare commit
+        if: >-
+          steps.ml.outputs.has_updated_sources == 1 &&
+          (
+            env.APPLY_FIXES_EVENT == 'all' ||
+            env.APPLY_FIXES_EVENT == github.event_name
+          ) &&
+          env.APPLY_FIXES_MODE == 'commit' &&
+          github.ref != 'refs/heads/main' &&
+          (
+            github.event_name == 'push' ||
+            github.event.pull_request.head.repo.full_name == github.repository
+          ) &&
+          !contains(github.event.head_commit.message, 'skip fix')
+        run: sudo chown -Rc $UID .git/
+
+      - name: Commit and push applied linter fixes
+        uses: stefanzweifel/git-auto-commit-action@v6
+        if: >-
+          steps.ml.outputs.has_updated_sources == 1 &&
+          (
+            env.APPLY_FIXES_EVENT == 'all' ||
+            env.APPLY_FIXES_EVENT == github.event_name
+          ) &&
+          env.APPLY_FIXES_MODE == 'commit' &&
+          github.ref != 'refs/heads/main' &&
+          (
+            github.event_name == 'push' ||
+            github.event.pull_request.head.repo.full_name == github.repository
+          ) &&
+          !contains(github.event.head_commit.message, 'skip fix')
+        with:
+          branch: >-
+            ${{
+              github.event.pull_request.head.ref ||
+              github.head_ref ||
+              github.ref
+            }}
+          commit_message: "[MegaLinter] Apply linters fixes"
+          commit_user_name: megalinter-bot
+          commit_user_email: 129584137+megalinter-bot@users.noreply.github.com

.gitignore

@@ -3,3 +3,4 @@ out/
 .vs/
 .cache/
 *~
+megalinter-reports/

.mega-linter.yml

@@ -0,0 +1,28 @@
+# Configuration file for MegaLinter
+#
+# See all available variables at https://megalinter.io/latest/config-file/ and in
+# linters documentation
+
+# all, none, or list of linter keys
+APPLY_FIXES: none
+
+# If you use ENABLE variable, all other languages/formats/tooling-formats will
+# be disabled by default
+# ENABLE:
+
+# If you use ENABLE_LINTERS variable, all other linters will be disabled by
+# default
+ENABLE_LINTERS:
+  - SPELL
+  - CPP_CLANG_FORMAT
+
+# DISABLE:
+  # - COPYPASTE # Uncomment to disable checks of excessive copy-pastes
+  # - SPELL # Uncomment to disable checks of spelling mistakes
+
+SHOW_ELAPSED_TIME: true
+
+# Uncomment if you want MegaLinter to detect errors but not block CI to pass
+DISABLE_ERRORS: true
+
+FLAVOR_SUGGESTIONS: false

CMakeLists.txt

@@ -1,10 +1,12 @@
 cmake_minimum_required(VERSION 3.23)
 
-project(pixelarium VERSION 0.0.1)
+project(pixelarium VERSION 0.0.12)
+
+list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
 
 set(CMAKE_VERBOSE_MAKEFILE ON)
-set(CXX_STANDARD 20)
-set(CXX_STANDARD_REQUIRED true)
+set(CMAKE_CXX_STANDARD 23)
+set(CMAKE_CXX_STANDARD_REQUIRED true)
 
 # setting global module directories
 set(glfw3_module_DIR ${PROJECT_SOURCE_DIR}/modules/glfw)
@@ -13,40 +15,66 @@ set(imgui_DIR ${PROJECT_SOURCE_DIR}/modules/imgui)
 set(pfd_DIR ${PROJECT_SOURCE_DIR}/modules/portable-file-dialogs)
 set(spdlog_DIR ${PROJECT_SOURCE_DIR}/modules/spdlog)
 
-find_package(OpenGL REQUIRED)
-
 message(STATUS "GLFW:\t" ${glfw3_module_DIR})
 message(STATUS "PFD:\t\t" ${pfd_DIR})
 message(STATUS "SPDLOG:\t" ${spdlog_DIR})
 
 #====================
 # Options
-option(PIXELARIUM_BUILD_UNITTESTS "Generate Unittests" ON)
-option(PIXELARIUM_BUILD_DOCS      "Generate Documentation" ON)
+option(PIXELARIUM_BUILD_UNITTESTS "Generate Unittests"                        ON)
+option(PIXELARIUM_BUILD_DOCS      "Generate Documentation"                    ON)
+option(PIXELARIUM_BUILD_DOCS_ONLY "Build only Documentation (no compilation)" OFF)
+option(PIXELARIUM_BUILD_EXAMPLES  "Build example projects"                    ON)
 #====================
 
+string(TOUPPER "${CMAKE_PROJECT_NAME}" PIXELARIUM_TITLE)
+
+if(PIXELARIUM_BUILD_DOCS OR PIXELARIUM_BUILD_DOCS_ONLY)
+  find_package(Doxygen REQUIRED)
+  include(awesomeDoxygen)
+  set(MAINPAGE_FILE "${PROJECT_SOURCE_DIR}/doc/index.md")
+
+  set(DOXYGEN_IN ${PROJECT_SOURCE_DIR}/doc/Doxyfile.in)
+  set(DOXYGEN_OUT ${CMAKE_BINARY_DIR}/Doxyfile)
+
+  configure_file(${DOXYGEN_IN} ${DOXYGEN_OUT} @ONLY)
+  message(STATUS "Building Docs")
+
+  add_custom_target(doxygen ALL
+    COMMAND ${DOXYGEN_EXECUTABLE} ${DOXYGEN_OUT}
+    WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
+    COMMENT "Generating Docs")
+
+  if(PIXELARIUM_BUILD_DOCS_ONLY)
+    message(STATUS "Documentation Generated successful")
+    list(APPEND CMAKE_MESSAGE_INDENT "  ")
+    message(STATUS "PIXELARIUM_BUILD_DOCS_ONLY was set to ON. Thus, no compilation will follow.")
+    message(STATUS "If compilation shall occur, set '-DPIXELARIUM_BUILD_DOCS_ONLY=OFF'.")
+    list(POP_BACK CMAKE_MESSAGE_INDENT)
+
+    return()
+  endif()
+endif()
+
+find_package(OpenGL REQUIRED)
+
 if(WIN32)
   set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
   if (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
-    set(CMAKE_CXX_FLAGS "/std:c++20 /Zi /EHsc")
+    set(CMAKE_CXX_FLAGS "/Zi /EHsc")
   else()
-    set(CMAKE_CXX_FLAGS "-Wall -Wextra -g --std=c++20")
+    set(CMAKE_CXX_FLAGS "-Wall -Wextra -g")
   endif()
 endif()
 if(UNIX)
-  set(CMAKE_CXX_FLAGS "-Wall -Wextra -g --std=c++20")
+  set(CMAKE_CXX_FLAGS "-Wall -Wextra -g")
 endif()
 
-string(TOUPPER "${CMAKE_PROJECT_NAME}" PIXELARIUM_TITLE)
-
 add_subdirectory(${pfd_DIR})
 add_subdirectory(${spdlog_DIR})
 add_subdirectory(${glfw3_module_DIR})
 add_subdirectory(lib)
 
-set(SRC
-  src/main.cpp)
-
 #====================
 # needed for the spdlogger implementation
 # this is not nice, but it won't work when, e.g. doing it from lower level cmake files
@@ -54,49 +82,12 @@ add_compile_options("$<$<C_COMPILER_ID:MSVC>:/utf-8>")
 add_compile_options("$<$<CXX_COMPILER_ID:MSVC>:/utf-8>")
 #====================
 
-add_executable(${PROJECT_NAME} ${SRC})
-
-target_link_libraries(${PROJECT_NAME}
-  PRIVATE pixelariumimagelib
-  PRIVATE pixelariumrenderlib
-  PRIVATE pixelariumutilslib
-  PRIVATE pixelariumresourcelib
-  PUBLIC pixelariumapplicationlib)
-
-target_include_directories(${PROJECT_NAME}
-  PUBLIC ${PROJECT_SOURCE_DIR}/src
-  PUBLIC ${PROJECT_SOURCE_DIR}/lib
-  PUBLIC ${PROJECT_SOURCE_DIR}/lib/imaging
-  PUBLIC ${PROJECT_SOURCE_DIR}/lib/app
-  PUBLIC ${spdlog_DIR}/include
-  PUBLIC ${LIBCZI_INCLUDE_DIR}
-  PUBLIC ${CMAKE_CURRENT_BINARY_DIR})
-
+if(PIXELARIUM_BUILD_EXAMPLES)
+  add_subdirectory(examples)
+endif()
 
 if(PIXELARIUM_BUILD_UNITTESTS)
   include(CTest)
   enable_testing()
   add_subdirectory(tests)
 endif()
-
-if(PIXELARIUM_BUILD_DOCS)
-  include(${PROJECT_SOURCE_DIR}/cmake/awesomeDoxygen.cmake)
-  set(MAINPAGE_FILE "doc/index.md")
-  find_package(Doxygen)
-  if (DOXYGEN_FOUND)
-
-    set(DOXYGEN_IN ${PROJECT_SOURCE_DIR}/doc/Doxyfile.in)
-    set(DOXYGEN_OUT ${CMAKE_BINARY_DIR}/Doxyfile)
-
-    configure_file(${DOXYGEN_IN} ${DOXYGEN_OUT} @ONLY)
-    message(STATUS "Building Docs")
-
-    add_custom_target(doxygen ALL
-      COMMAND ${DOXYGEN_EXECUTABLE} ${DOXYGEN_OUT}
-      WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
-      COMMENT "Generating Docs")
-
-  else (DOXYGEN_FOUND)
-    message(FATAL_ERROR "Doxygen need to be installed to generate the doxygen documentation")
-  endif (DOXYGEN_FOUND)
-endif()

CMakePresets.json

@@ -16,7 +16,9 @@
         "FETCHCONTENT_FULLY_DISCONNECTED": "OFF",
         "CMAKE_VERBOSE_MAKEFILE": "ON",
         "PIXELARIUM_BUILD_UNITTESTS": "ON",
-        "PIXELARIUM_BUILD_DOCS": "OFF"
+        "PIXELARIUM_BUILD_DOCS": "ON",
+        "PIXELARIUM_BUILD_DOCS_ONLY": "OFF",
+        "PIXELARIUM_BUILD_EXAMPLES": "ON"
       }
     },
     {
@@ -52,8 +54,7 @@
       "cacheVariables": {
         "CMAKE_C_COMPILER": "gcc",
         "CMAKE_CXX_COMPILER": "g++",
-        "CMAKE_BUILD_TYPE": "Debug",
-        "PIXELARIUM_BUILD_DOCS": "ON"
+        "CMAKE_BUILD_TYPE": "Debug"
       }
     }
   ],

Readme.org

@@ -6,6 +6,9 @@
 #+author: Maximilian Kueffner
 #+exclude_tags: noexport
 
+[[https://github.com/m-aXimilian/pixelarium/actions/workflows/ci-workflow.yml][file:https://github.com/m-aXimilian/pixelarium/actions/workflows/ci-workflow.yml/badge.svg]]
+[[https://github.com/m-aXimilian/pixelarium/actions/workflows/mega-linter.yml][file:https://github.com/m-aXimilian/pixelarium/actions/workflows/mega-linter.yml/badge.svg]]
+
 * Synopsis
 
 Pixelarium strives to be a batteries-included visualizer application used in conjunction with an externally implemented and linked arbitrary functionality.
@@ -14,6 +17,17 @@ It tries to be as flexible as possible.
 
 This is still work in progress and will change significantly.
 
+* Supported Types
+
+Currently, Pixelarium supports the following image file formats:
+- jpeg
+- png
+- tiff
+- czi
+
+
+where possible, the [[https://docs.opencv.org/3.4/d4/da8/group__imgcodecs.html][OpenCV codecs]] are used to interpret the respective file type. The czi-format is supported via [[https://github.com/ZEISS/libczi][libCZI]].
+
 * Prerequisites
 
 Dependencies are either submodules in the =modules= subdirectory or artifacts of the cmake build process from the =cmake= directory. This repository should therefore be cloned recursively:
@@ -60,5 +74,44 @@ If you want to specify compiler settings and options which are not defined in a
   cmake --build build
 #+end_src
 
-* TODO Example
+* Usage
 
+All there is to do in order to get an initial window on screen is to create an instance of [[file:lib/app/AppGLFW.hpp][=AppGLFW=]] (or one of its child classes) and start it.
+
+#+begin_src C++
+  unique_ptr<ILog> logger = make_unique<SpdLogger>("logfile.log", "loggername");
+  ImageResourcePool image_pool;
+
+  auto app {DefaultApp(*logger, image_pool)};
+  app.Start();
+#+end_src
+
+This will get the default application on screen which looks like
+[[file:doc/figures/default-app.png]]
+
+
+The [[file:examples/][examples]] directory aims to showcase a few usage examples of this project.
+
+** [[file:examples/simple/][simple]]
+
+This is the most straight-forward usage of Pixelarium. It simply instantiates a [[file:lib/app/DefaultApp.hpp][=DefaultApp=]] and runs it.
+
+** [[file:examples/custom_0/][custom_0]]
+
+This is meant to showcase that [[file:lib/app/DefaultApp.hpp][=DefaultApp=]] ([[file:lib/app/AppGLFW.hpp][=AppGLFW=]] as well) is meant to be customized via inheritance.
+As a usage example, it implements a simple binary image reader. It can be presented with a binary file of layout
+#+begin_src C++
+  struct ParsedImage
+  {
+      uint8_t depth;
+      uint8_t channels;
+      uint16_t width;
+      uint16_t height;
+      void* data;
+  };
+#+end_src
+i.e., a header encoding 1 byte for the pixel-depth, 1 byte for the channel count, 2 byte each for width and height in pixel followed by the actual pixeldata.
+
+** [[file:examples/custom_1/][custom_1]]
+
+An example showcasing how to inject a user defined control into the existing scaffolding of =DefaultApp= using a multiplication filter. This is in many ways similar to the previous example.

cmake/awesomeDoxygen.cmake

@@ -2,6 +2,7 @@ include(FetchContent)
 FetchContent_Declare(
     doxygen-awesome-css
     URL https://github.com/jothepro/doxygen-awesome-css/archive/refs/heads/main.zip
+    DOWNLOAD_EXTRACT_TIMESTAMP 1
 )
 FetchContent_MakeAvailable(doxygen-awesome-css)
 

cmake/implot.cmake

@@ -0,0 +1,9 @@
+include(FetchContent)
+FetchContent_Declare(
+  implot
+  URL https://github.com/epezent/implot/archive/refs/tags/v0.17.zip
+  DOWNLOAD_EXTRACT_TIMESTAMP 1)
+
+FetchContent_MakeAvailable(implot)
+
+FetchContent_GetProperties(implot SOURCE_DIR IMPLOT_DIR)

cmake/libCZI.cmake

@@ -3,17 +3,21 @@ include(FetchContent)
 FetchContent_Declare(
   libCZI
   GIT_REPOSITORY https://github.com/ZEISS/libczi.git
-  GIT_TAG        593ee17587214358c535bd036473b1b62945e637
+  GIT_TAG        main
+  DOWNLOAD_EXTRACT_TIMESTAMP 1
 )
 
 if(NOT libCZI_POPULATED)
   message(STATUS "Fetching libCZI")
-  FetchContent_MakeAvailable(libCZI)
 
-  set(LIBCZI_BUILD_CZICMD OFF CACHE BOOL "" FORCE)
-  set(LIBCZI_BUILD_DYNLIB OFF CACHE BOOL "" FORCE)
-  set(LIBCZI_BUILD_UNITTESTS OFF CACHE BOOL "" FORCE)
-  set(LIBCZI_DO_NOT_SET_MSVC_RUNTIME_LIBRARY  ON CACHE BOOL "" FORCE)
+  set(LIBCZI_BUILD_CZICMD                           OFF CACHE BOOL "Don't build commandline libCZI." FORCE)
+  set(LIBCZI_BUILD_DYNLIB                           OFF CACHE BOOL "Don't build libCZI as a shared library." FORCE)
+  set(LIBCZI_BUILD_UNITTESTS                        OFF CACHE BOOL "Don't build libCZI unit tests." FORCE)
+  set(LIBCZI_BUILD_PREFER_EXTERNALPACKAGE_RAPIDJSON OFF CACHE BOOL "Use internal rapidjson." FORCE)
+  set(LIBCZI_DO_NOT_SET_MSVC_RUNTIME_LIBRARY        ON  CACHE BOOL "Consumer sets the runtime." FORCE)
+  set(ADDITIONAL_LIBS_REQUIRED_FOR_ATOMIC           ""  CACHE STRING "Additional atomic libs included." FORCE)
+
+  FetchContent_MakeAvailable(libCZI)
 endif()
 
 FetchContent_GetProperties(libCZI)

cmake/testgoogle.cmake

@@ -2,10 +2,11 @@ include(FetchContent)
 FetchContent_Declare(
   googletest
   URL https://github.com/google/googletest/archive/refs/tags/v1.14.0.zip
+  DOWNLOAD_EXTRACT_TIMESTAMP 1
 )
+
 # From this documentation: https://google.github.io/googletest/quickstart-cmake.html
 # For Windows: Prevent overriding the parent project's compiler/linker settings
-
 if(WIN32)
   set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
 endif()

doc/Doxyfile.in

@@ -2,16 +2,22 @@ PROJECT_NAME           = @PIXELARIUM_TITLE@
 PROJECT_NUMBER         = @CMAKE_PROJECT_VERSION@
 
 OUTPUT_DIRECTORY       = @PROJECT_BINARY_DIR@/doc
-INPUT                  = @PROJECT_SOURCE_DIR@/lib/app \
-                         @PROJECT_SOURCE_DIR@/doc \
-                         @PROJECT_SOURCE_DIR@/lib/imaging \
-                         @PROJECT_SOURCE_DIR@/lib/imaging/impl \
-                         @PROJECT_SOURCE_DIR@/lib/utilities \
-                         @PROJECT_SOURCE_DIR@/lib/rendering \
-                         @PROJECT_SOURCE_DIR@/lib/resources
+INPUT                  = @PROJECT_SOURCE_DIR@/doc/ \
+                         @PROJECT_SOURCE_DIR@/lib/app/include \
+                         @PROJECT_SOURCE_DIR@/lib/app/rendering/include \
+                         @PROJECT_SOURCE_DIR@/lib/imaging/include \
+                         @PROJECT_SOURCE_DIR@/lib/imaging/impl/include \
+                         @PROJECT_SOURCE_DIR@/lib/utilities/include \
+                         @PROJECT_SOURCE_DIR@/lib/resources/include
+IMAGE_PATH             = @PROJECT_SOURCE_DIR@/doc/figures
 
 DOXYFILE_ENCODING      = UTF-8
 GENERATE_LATEX         = NO
 FULL_PATH_NAMES        = NO
-USE_MDFILE_AS_MAINPAGE = @PROJECT_SOURCE_DIR@/doc/index.md
+USE_MDFILE_AS_MAINPAGE = @MAINPAGE_FILE@
+
+
 HTML_EXTRA_STYLESHEET  = @AWESOME_CSS_DIR@/doxygen-awesome.css
+GENERATE_TREEVIEW      = YES
+DISABLE_INDEX          = NO
+FULL_SIDEBAR           = NO

doc/index.md

@@ -52,5 +52,48 @@ If you want to specify compiler settings and options which are not defined in a
     cmake -B build -S .
     cmake --build build
 
+# Usage
+
+The [examples](https://github.com/m-aXimilian/pixelarium/tree/main/examples) directory aims to showcase a few usage examples of this project.
+
+All there is to do in order to get an initial window on screen is to create an instance of [`AppGLFW`](https://github.com/m-aXimilian/pixelarium/blob/main/lib/app/include/AppGLFW.hpp) (or one of its child classes) and start it.
+
+```cpp
+  const auto logger {SpdLogger("logfile.log", "loggername")};
+  ImageResourcePool image_pool;
+
+  auto app {DefaultApp(logger, image_pool)};
+  app.Start();
+```
 
 
+![Default App Screenshot](default-app.png)
+
+
+## simple
+
+This is the most straight-forward usage of Pixelarium. It simply instantiates a [`DefaultApp`](https://github.com/m-aXimilian/pixelarium/blob/main/lib/app/include/DefaultApp.hpp) and runs it.
+
+
+## custom_0
+
+This is meant to showcase that [`DefaultApp`]((https://github.com/m-aXimilian/pixelarium/blob/main/lib/app/include/DefaultApp.hpp)) ([`AppGLFW`](https://github.com/m-aXimilian/pixelarium/blob/main/lib/app/include/AppGLFW.hpp) as well) can be customized via inheritance.
+
+As a usage example, it implements a simple binary image reader. It can be presented with a binary file of layout
+
+```cpp
+    struct ParsedImage
+    {
+        uint8_t depth;
+        uint8_t channels;
+        uint16_t width;
+        uint16_t height;
+        void* data;
+    };
+```
+
+i.e., a header encoding 1 byte for the pixel-depth, 1 byte for the channel count, 2 byte each for width and height in pixel followed by the actual pixeldata.
+
+## custom_1
+
+An example showcasing how to inject a user defined control into the existing scaffolding of `DefaultApp` using a multiplication filter. This is in many ways similar to the previous example.

doc/versions.md

@@ -0,0 +1,18 @@
+# Version History
+
+| Version  | Description                                                                                                 |
+|:--------:|:------------------------------------------------------------------------------------------------------------|
+|   0.0.12 | Build system simplifications, binary image-reader in custom\_0, a simple POC for histograms in views        |
+|   0.0.11 | Miscellaneous refactoring                                                                                   |
+|   0.0.10 | Adds Tiff-support, in-memory images, and advances usage example "custom_1"                                  |
+|   0.0.9  | Improve documentation, add example for `DefaultApp` override semantics                                      |
+|   0.0.8  | Init example projects                                                                                       |
+|   0.0.7  | Refactors image gallery logic from `DefaultApp` into a separate module                                      |
+|   0.0.6  | Added documentation-only option `PIXELARIUM_BUILD_DOCS_ONLY`, libCZI upgrade to main branch CI improvements |
+|   0.0.5  | Compile for C++23 and code style adaptions                                                                  |
+|   0.0.4  | Fix MSVC build, some cosmetics, explicit initial window size for images                                     |
+|   0.0.3  | Fetch subblocks based on the dimension selection sliders                                                    |
+|   0.0.2  | Add Dimension selector sliders to CZI image view                                                            |
+|   0.0.1  | Initiate CZI image view                                                                                     |
+|   0.0.0  | Initial version                                                                                             |
+

examples/CMakeLists.txt

@@ -0,0 +1,3 @@
+add_subdirectory(simple)
+add_subdirectory(custom_0)
+add_subdirectory(custom_1)

examples/custom_0/CMakeLists.txt

@@ -0,0 +1,9 @@
+set(SRC
+  ${CMAKE_CURRENT_SOURCE_DIR}/custom_0.cpp)
+
+set(CUSTOM_0_NAME "${PROJECT_NAME}_custom_app")
+
+add_executable(${CUSTOM_0_NAME} ${SRC})
+
+target_link_libraries(${CUSTOM_0_NAME}
+  PRIVATE pixelarium::lib::application_static)

examples/custom_0/custom_0.cpp

@@ -0,0 +1,226 @@
+#include <opencv2/core/hal/interface.h>
+
+#include <cstdint>
+#include <filesystem>
+#include <format>
+#include <fstream>
+#include <memory>
+#include <string>
+
+#include "DefaultApp.hpp"
+#include "ILog.hpp"
+#include "PixelariumLogger.hpp"
+#include "PixelariumMem.hpp"
+#include "imgui.h"
+#include "implot.h"
+#include "portable-file-dialogs.h"
+#include "resource.hpp"
+
+using namespace pixelarium;
+using namespace std;
+using Log = utils::log::ILog;
+using Pool = resources::ImageResourcePool;
+
+// setup a logger
+#ifdef _WIN32
+auto logger{utils::log::PixelariumLogger("pixellog", string(getenv("APPDATA")) + "/pixelarium/simple_app.log")};
+#else
+auto logger{utils::log::PixelariumLogger("pixellog", string(getenv("HOME")) + "/.cache/pixelarium/simple_app.log")};
+#endif
+
+// instantiate an image pool for the application
+resources::ImageResourcePool image_pool;
+
+constexpr auto ToCVPixelType(size_t depth, size_t chans)
+{
+    int tp{};
+    switch (depth)
+    {
+        case 8:
+            tp = CV_8U;
+            break;
+        case 16:
+            tp = CV_16U;
+            break;
+        default:
+            return -1;
+    }
+
+    if (chans > 1)
+    {
+        return static_cast<int>(CV_MAKETYPE(tp, chans));
+    }
+
+    return tp;
+}
+
+struct StatusReport
+{
+    const std::function<void(const std::string&)> report_status;
+    const std::function<void()> reset_status;
+};
+
+class BinaryReader
+{
+   private:
+    filesystem::path bin_file{};
+    vector<std::byte> buffer{};
+    uintmax_t file_size;
+
+#pragma pack(push, 1)
+    struct ParsedImage
+    {
+        uint8_t depth;
+        uint8_t channels;
+        uint16_t width;
+        uint16_t height;
+        void* data;
+    };
+#pragma pack(pop)
+
+    auto RegisterImage(const ParsedImage& img, string& name, const StatusReport& report) -> void
+    {
+        if (img.width == 0 || img.height == 0 || img.channels == 0 || img.depth == 0 || !img.data)
+        {
+            report.reset_status();
+            report.report_status(
+                format("Parsing {} failed: Dimensions (w: {}, h: {}, d: {}, c: {}) cannot be parsed! The provided "
+                       "bin-file is probably corrupted.",
+                       name, img.width, img.height, img.depth, img.channels));
+            return;
+        }
+
+        auto tmp_mat =
+            cv::Mat(img.height, img.width, ToCVPixelType(img.depth, img.channels), const_cast<void*>(img.data));
+        // not cloning is a dangling reference once the externally managed data pointer is freed
+        auto mat{tmp_mat.clone()};
+
+        image_pool.SetResource(make_unique<imaging::PixelariumMem>(mat, name.c_str(), logger));
+    }
+
+    auto ReadFile(const filesystem::path& file, const StatusReport& report) -> ParsedImage
+    {
+        uint8_t depth{};
+        uint8_t channels{};
+        uint16_t width{};
+        uint16_t height{};
+        uint64_t pixel_count{};
+
+        if (!filesystem::exists(file)) return {};
+
+        auto sz = filesystem::file_size(file);
+        // header layout of binary file
+        // | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 |
+        // | ^ | ^ |     ^ |   ^   |        pixel count in byte        |
+        //   |   |______ |__   |
+        // pixel depth |   |  height in px
+        //             |  width in px
+        //       channel count
+        constexpr auto header_size{14};
+
+        bool can_read = sz >= header_size;
+
+        if (!can_read) return {};
+
+        if (!buffer.empty())
+        {
+            buffer.clear();
+        }
+
+        ifstream inp_stream(file, ios::binary);
+        if (inp_stream)
+        {
+            inp_stream.read(reinterpret_cast<char*>(&width), sizeof(width));
+            inp_stream.read(reinterpret_cast<char*>(&height), sizeof(height));
+            inp_stream.read(reinterpret_cast<char*>(&depth), sizeof(depth));
+            inp_stream.read(reinterpret_cast<char*>(&channels), sizeof(channels));
+            inp_stream.read(reinterpret_cast<char*>(&pixel_count), sizeof(pixel_count));
+            logger.Info(format("{}(): Pixel count {}", __FUNCTION__, pixel_count));
+
+            if (pixel_count <= sz - header_size)
+            {
+                buffer.resize(pixel_count);
+                inp_stream.read(reinterpret_cast<char*>(buffer.data()), pixel_count);
+            }
+        }
+
+        logger.Info(format("{}: Parsed image with width: {}, height: {}, depth: {}, channels: {}", __PRETTY_FUNCTION__,
+                           width, height, depth, channels));
+        report.report_status(
+            format("Parsed image with width: {}, height: {}, depth: {}, channels: {}", width, height, depth, channels));
+
+        return {.depth = depth, .channels = channels, .width = width, .height = height, .data = buffer.data()};
+    }
+
+   public:
+    auto Present(const StatusReport& report) -> void
+    {
+        using namespace ImGui;
+        SetNextWindowSize({256, 124});
+        Begin("Load Binary File");
+        if (Button("Load File"))
+        {
+            auto res{pfd::open_file("Load Inputs", pfd::path::home(), {"Bin Files", "*.bin"}).result()};
+            if (!res.empty()) bin_file = filesystem::path(res.at(0));
+        }
+
+        if (filesystem::exists(bin_file))
+        {
+            file_size = filesystem::file_size(bin_file);
+            Text("File: %s (%ju)", bin_file.filename().c_str(), file_size);
+            if (Button("Parse File"))
+            {
+                auto buff = ReadFile(bin_file, report);
+                auto name = bin_file.filename().string();
+                RegisterImage(buff, name, report);
+            }
+        }
+
+        End();
+    }
+};
+
+// create a custom app inheriting from the library's default app
+class MyApp : public application::DefaultApp
+{
+   private:
+    BinaryReader bin_read;
+    bool plot_demop_{false};
+
+   public:
+    MyApp(const Log& log, Pool& pool) : application::DefaultApp(log, pool) {}
+    ~MyApp() {}
+
+    // override some of the defaults member functions
+    void Run() override;
+    void MenuBarOptionsColumn1() override;
+    void MenuBarOptionsColumn2() override {};
+};
+
+int main()
+{
+    // some initial log message
+    logger.Info(std::format("{}: Starting Application {}", __FUNCTION__, "Pixelarium"));
+
+    // create a custom application, inject its dependencies and start it
+    auto app{MyApp(logger, image_pool)};
+
+    app.Start();
+}
+
+void MyApp::Run()
+{
+    this->gallery_.RenderGallery();
+    this->gallery_.RenderImages();
+    const auto reporter =
+        StatusReport{.report_status = [this](const std::string& msg) { this->SetStatusTimed(msg, 5); },
+                     .reset_status = [this]() { this->ResetStatus(); }};
+    bin_read.Present(reporter);
+
+    if (plot_demop_)
+    {
+        ImPlot::ShowDemoWindow(&plot_demop_);
+    }
+}
+
+void MyApp::MenuBarOptionsColumn1() { ImGui::MenuItem("Show Plotdemos", NULL, &this->plot_demop_); }

examples/custom_1/CMakeLists.txt

@@ -0,0 +1,9 @@
+set(SRC
+  ${CMAKE_CURRENT_SOURCE_DIR}/custom_1.cpp)
+
+set(CUSTOM_1_NAME "${PROJECT_NAME}_custom1_app")
+
+add_executable(${CUSTOM_1_NAME} ${SRC})
+
+target_link_libraries(${CUSTOM_1_NAME}
+  PRIVATE pixelariumapplicationlib)

examples/custom_1/custom_1.cpp

@@ -0,0 +1,147 @@
+#include <opencv2/core/hal/interface.h>
+
+#include <ctime>
+#include <memory>
+#include <opencv2/core/base.hpp>
+#include <opencv2/core/mat.hpp>
+#include <opencv2/imgproc.hpp>
+#include <string>
+
+#include "DefaultApp.hpp"
+#include "ILog.hpp"
+#include "IPixelariumImage.hpp"
+#include "PixelariumMem.hpp"
+#include "SpdLogger.hpp"
+#include "imgui.h"
+#include "resource.hpp"
+
+using namespace pixelarium;
+using namespace std;
+using Log = utils::log::ILog;
+using Pool = resources::ImageResourcePool;
+
+// setup a logger
+#ifdef _WIN32
+unique_ptr<Log> logger{
+    make_unique<utils::log::SpdLogger>(string(getenv("APPDATA")) + "/pixelarium/simple_app.log", "default")};
+#else
+unique_ptr<Log> logger{
+    make_unique<utils::log::SpdLogger>(string(getenv("HOME")) + "/.cache/pixelarium/simple_app.log", "default")};
+#endif
+
+// instantiate an image pool for the application
+resources::ImageResourcePool image_pool;
+
+class Selector
+{
+    using Pool = resources::ImageResourcePool;
+    Pool& pool_;
+    std::string preview_0_{"None"};
+    std::string preview_1_{"None"};
+    resources::ResourceKey selected_key_0;
+    resources::ResourceKey selected_key_1;
+    int idx_{0};
+
+   public:
+    Selector(resources::ImageResourcePool& pool) : pool_(pool) {}
+    void SelectImage()
+    {
+        ImGui::Begin("Image Multiply");
+        static int selected_idx_0{0};
+        static int selected_idx_1{0};
+        if (ImGui::BeginCombo("Select first image", preview_0_.c_str()))
+        {
+            pool_.Enumerate(
+                [&](resources::ResourceKey key, size_t idx, const imaging::IPixelariumImage<cv::Mat>& img) -> void
+                {
+                    const bool is_selected = static_cast<int>(idx) == selected_idx_0;
+                    if (ImGui::Selectable(img.Name().c_str(), is_selected))
+                    {
+                        selected_idx_0 = idx;
+                        preview_0_ = img.Name();
+                        selected_key_0 = key;
+                    }
+
+                    if (is_selected)
+                    {
+                        ImGui::SetItemDefaultFocus();
+                    }
+                });
+
+            ImGui::EndCombo();
+        }
+
+        if (ImGui::BeginCombo("Select second image", preview_1_.c_str()))
+        {
+            pool_.Enumerate(
+                [&](resources::ResourceKey key, size_t idx, const imaging::IPixelariumImage<cv::Mat>& img) -> void
+                {
+                    const bool is_selected = static_cast<int>(idx) == selected_idx_1;
+                    if (ImGui::Selectable(img.Name().c_str(), is_selected))
+                    {
+                        selected_idx_1 = idx;
+                        preview_1_ = img.Name();
+                        selected_key_1 = key;
+                    }
+
+                    if (is_selected)
+                    {
+                        ImGui::SetItemDefaultFocus();
+                    }
+                });
+
+            ImGui::EndCombo();
+        }
+
+        if (ImGui::Button("Process"))
+        {
+            auto img0 = pool_.GetResource(selected_key_0);
+            auto img_mat0 = img0.lock()->TryGetImage();
+            auto img1 = pool_.GetResource(selected_key_1);
+            auto img_mat1 = img1.lock()->TryGetImage();
+
+            if (!img_mat0.has_value() || !img_mat1.has_value() || img_mat0.value().empty() || img_mat1.value().empty())
+                return;
+
+            if (img_mat0->size != img_mat1->size) return;
+
+            cv::multiply(img_mat0.value(), img_mat1.value(), img_mat0.value());
+
+            std::string name{std::format("Multiply_{}", idx_)};
+            pool_.SetResource(std::make_unique<imaging::PixelariumMem>(*img_mat0, name, *logger));
+
+            ++idx_;
+        }
+
+        ImGui::End();
+    }
+};
+
+// create a custom app inheriting from the library's default app
+class MyApp : public application::DefaultApp
+{
+    Selector select_;
+
+   public:
+    MyApp(const Log& log, Pool& pool) : application::DefaultApp(log, pool), select_(pool) {}
+
+    // override some of the defaults member functions
+    void Run() override;
+};
+
+int main()
+{
+    // some initial log message
+    logger->Info(std::format("{}: Starting Application {}", __FUNCTION__, "Pixelarium"));
+
+    // create a custom application, inject its dependencies and start it
+    auto app{MyApp(*logger, image_pool)};
+
+    app.Start();
+}
+
+void MyApp::Run()
+{
+    application::DefaultApp::Run();
+    select_.SelectImage();
+}

examples/simple/CMakeLists.txt

@@ -0,0 +1,10 @@
+set(SRC
+  ${CMAKE_CURRENT_SOURCE_DIR}/simple.cpp)
+
+set(SIMPLE_NAME "${PROJECT_NAME}_SIMPLE")
+
+add_executable(${SIMPLE_NAME} ${SRC})
+
+target_link_libraries(${SIMPLE_NAME}
+  PRIVATE pixelariumapplicationlib)
+

examples/simple/simple.cpp

@@ -0,0 +1,33 @@
+#include <memory>
+
+#include "DefaultApp.hpp"
+#include "ILog.hpp"
+#include "SpdLogger.hpp"
+#include "resource.hpp"
+
+using namespace pixelarium;
+using namespace std;
+using Log = utils::log::ILog;
+using Pool = resources::ImageResourcePool;
+
+// setup a logger
+#ifdef _WIN32
+const auto logger{utils::log::SpdLogger(string(getenv("APPDATA")) + "/pixelarium/simple_app.log", "default")};
+#else
+const auto logger{
+    utils::log::SpdLogger(string(getenv("HOME")) + "/.cache/pixelarium/simple_app.log", "default")};
+#endif
+
+int main()
+{
+    // some initial log message and default log level setting
+    logger.Info(format("{}: Starting Application {}", __FUNCTION__, "Pixelarium"));
+    logger.ChangeLevel(utils::log::LogLevel::kDebug);
+
+    // instantiate an image pool for the application
+    resources::ImageResourcePool image_pool;
+
+    // create an application, inject its dependencies and start it
+    auto app{application::DefaultApp(logger, image_pool)};
+    app.Start();
+}

lib/CMakeLists.txt

@@ -1,5 +1,4 @@
 add_subdirectory(utilities)
 add_subdirectory(imaging)
-add_subdirectory(rendering)
 add_subdirectory(resources)
 add_subdirectory(app)

lib/app/AppGLFW.cpp

@@ -4,6 +4,56 @@
 #include "imgui.h"
 #include "imgui_impl_glfw.h"
 #include "imgui_impl_opengl3.h"
+#include "imgui_internal.h"
+#include "simple_thread_pool.hpp"
+
+// see https://github.com/ocornut/imgui/issues/3518
+bool PixelBeginStatusBar()
+{
+    using namespace ImGui;
+    ImGuiContext& g = *GImGui;
+    ImGuiViewportP* viewport = (ImGuiViewportP*)(void*)GetMainViewport();
+
+    SetCurrentViewport(NULL, viewport);
+
+    g.NextWindowData.MenuBarOffsetMinVal = ImVec2(
+        g.Style.DisplaySafeAreaPadding.x, ImMax(g.Style.DisplaySafeAreaPadding.y - g.Style.FramePadding.y, 0.0f));
+    ImGuiWindowFlags window_flags =
+        ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoSavedSettings | ImGuiWindowFlags_MenuBar;
+    float height = GetFrameHeight();
+    bool is_open = BeginViewportSideBar("##MainStatusBar", viewport, ImGuiDir_Up, height, window_flags);
+    g.NextWindowData.MenuBarOffsetMinVal = ImVec2(0.0f, 0.0f);
+    if (!is_open)
+    {
+        End();
+        return false;
+    }
+
+    g.CurrentWindow->Flags &= ~ImGuiWindowFlags_NoSavedSettings;
+    BeginMenuBar();
+    return is_open;
+}
+
+void PixelEndStatusBar()
+{
+    using namespace ImGui;
+    ImGuiContext& g = *GImGui;
+    if (!g.CurrentWindow->DC.MenuBarAppending)
+    {
+        IM_ASSERT_USER_ERROR(0, "Calling EndMainMenuBar() not from a menu-bar!");
+        return;
+    }
+
+    EndMenuBar();
+    g.CurrentWindow->Flags |= ImGuiWindowFlags_NoSavedSettings;
+
+    if (g.CurrentWindow == g.NavWindow && g.NavLayer == ImGuiNavLayer_Main && !g.NavAnyRequest && g.ActiveId == 0)
+        FocusTopMostWindowUnderOne(
+            g.NavWindow, NULL, NULL,
+            ImGuiFocusRequestFlags_UnlessBelowModal | ImGuiFocusRequestFlags_RestoreFocusedChild);
+
+    End();
+}
 
 /// @brief GLFW error callback function.
 /// @param error The error code.
@@ -84,14 +134,10 @@ void pixelarium::application::AppGLFW::InitMainWindow()
     IMGUI_CHECKVERSION();
     ImGui::CreateContext();
     ImGuiIO& io = ImGui::GetIO();
-    (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;  // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;   // Enable Gamepad Controls
     io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;      // Enable Docking
     io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;    // Enable Multi-Viewport / Platform
-                                                           // Windows
-    // io.ConfigViewportsNoAutoMerge = true;
-    // io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -168,20 +214,7 @@ void pixelarium::application::AppGLFW::MenuBar()
         // main menu
         if (ImGui::BeginMenu(MAINMENUNAME))
         {
-            if (ImGui::BeginCombo(LOGLEVELSELECT, LOGLEVELS[log_level_].data()))
-            {
-                for (int n = 0; n < static_cast<int>(LOGLEVELS.size()); n++)
-                {
-                    bool is_selected = (LOGLEVELS[log_level_] == LOGLEVELS[n]);
-                    if (ImGui::Selectable(LOGLEVELS[n].data(), is_selected))
-                    {
-                        log_level_ = n;
-                        this->logger_.ChangeLevel(static_cast<utils::log::LogLevel>(1 << log_level_));
-                    }
-                    if (is_selected) ImGui::SetItemDefaultFocus();
-                }
-                ImGui::EndCombo();
-            }
+            LogLevelSelect();
 
             // consumer main menu bar entries
             this->MenuBarOptionsColumn1();
@@ -197,6 +230,18 @@ void pixelarium::application::AppGLFW::MenuBar()
 
         ImGui::EndMainMenuBar();
     }
+
+    if (show_status_ && PixelBeginStatusBar())
+    {
+        if (ImGui::Button("Ok", {20, 20}))
+        {
+            show_status_ = false;
+            status_message_.clear();
+        }
+
+        ImGui::Text("%s", status_message_.c_str());
+        PixelEndStatusBar();
+    }
 }
 
 /// @brief Allows the user to select the log level via a combo box.
@@ -217,3 +262,14 @@ void pixelarium::application::AppGLFW::LogLevelSelect()
         ImGui::EndCombo();
     }
 }
+
+void pixelarium::application::AppGLFW::SetStatusTimed(const std::string& status, size_t seconds)
+{
+    SetStatus(status);
+    utils::pixelarium_pool::enqueue(
+        [this, seconds]()
+        {
+            std::this_thread::sleep_for(std::chrono::seconds(seconds));
+            ResetStatus();
+        });
+}

lib/app/AppGLFW.hpp

@@ -1,37 +0,0 @@
-#pragma once
-
-#include <GLFW/glfw3.h>
-
-#include <memory>
-
-#include "imgui.h"
-#include "utilities/ILog.hpp"
-
-namespace pixelarium::application
-{
-class AppGLFW
-{
-   public:
-    explicit AppGLFW(const utils::log::ILog& log) : logger_(log) { this->InitMainWindow(); }
-
-    void Start() { this->RunLoop(); }
-
-   protected:
-    virtual void MenuBarOptionsColumn1() {}
-    virtual void MenuBarOptionsColumn2() {}
-    virtual void MenuBarOptionsColumn3() {}
-    virtual void MenuBarOptionsColumn4() {}
-    virtual void MenuBarOptionsColumn5() {}
-    virtual void Run() {}
-
-    const utils::log::ILog& logger_;
-
-   private:
-    int RunLoop();
-    void InitMainWindow();
-    void MenuBar();
-    void LogLevelSelect();
-    int log_level_{0};
-    GLFWwindow* window = nullptr;
-};
-}  // namespace pixelarium::application

lib/app/CMakeLists.txt

@@ -1,28 +1,65 @@
+# Fetch implot
+include(implot)
+message(STATUS "IMPLOT sources at ${IMPLOT_DIR}")
+
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/app_resources_default.h.in
   ${CMAKE_BINARY_DIR}/app_resources_default.h @ONLY)
 
+set(IMPLOTSRC
+  "${IMPLOT_DIR}/implot.h"
+  "${IMPLOT_DIR}/implot_internal.h"
+  "${IMPLOT_DIR}/implot_items.cpp"
+  "${IMPLOT_DIR}/implot.cpp"
+  "${IMPLOT_DIR}/implot_demo.cpp"
+)
+
+set(IMGUISRC
+  "${imgui_DIR}/imgui.cpp"
+  "${imgui_DIR}/misc/cpp/imgui_stdlib.cpp"
+  "${imgui_DIR}/imgui_demo.cpp"
+  "${imgui_DIR}/imgui_draw.cpp"
+  "${imgui_DIR}/imgui_tables.cpp"
+  "${imgui_DIR}/imgui_widgets.cpp"
+  "${imgui_DIR}/backends/imgui_impl_opengl3.cpp"
+  "${imgui_DIR}/backends/imgui_impl_glfw.cpp")
+
 set(APPLIBSRC
-  AppGLFW.hpp
+  include/imgui_proxy.hpp
+  include/AppGLFW.hpp
+  include/DefaultApp.hpp
+  include/PixelariumGallery.hpp
   AppGLFW.cpp
-  DefaultApp.hpp
   DefaultApp.cpp
-  ${imgui_DIR}/imgui.cpp
-  ${imgui_DIR}/imgui_demo.cpp
-  ${imgui_DIR}/imgui_draw.cpp
-  ${imgui_DIR}/imgui_tables.cpp
-  ${imgui_DIR}/imgui_widgets.cpp
-  ${imgui_DIR}/backends/imgui_impl_opengl3.cpp
-  ${imgui_DIR}/backends/imgui_impl_glfw.cpp)
+  PixelariumGallery.cpp)
+
+set(RENDERSRC
+  rendering/include/RenderHelpers.hpp
+  rendering/include/RenderImageManager.hpp
+  rendering/include/CvMatRender.hpp
+  rendering/include/IPixelariumImageView.hpp
+  rendering/include/PixelariumImageViewDefault.hpp
+  rendering/include/PixelariumImageViewCzi.hpp
+  rendering/include/ImageViewFactory.hpp
+  rendering/RenderHelpers.cpp
+  rendering/CvMatRender.cpp
+  rendering/IPixelariumImageView.cpp
+  rendering/RenderImageManager.cpp
+  rendering/PixelariumImageViewDefault.cpp
+  rendering/PixelariumImageViewCzi.cpp
+  rendering/ImageViewFactory.cpp)
 
 set(APPLIBNAME pixelariumapplicationlib)
 
 add_library(${APPLIBNAME}
-  STATIC ${APPLIBSRC})
+  STATIC ${APPLIBSRC} ${IMGUISRC} ${IMPLOTSRC} ${RENDERSRC})
+
+add_library(pixelarium::lib::application_static ALIAS ${APPLIBNAME})
 
 target_link_libraries(${APPLIBNAME}
-  PRIVATE pixelariumutilslib
-  PRIVATE pixelariumimagelib
-  PRIVATE pixelariumrenderlib)
+  PUBLIC
+  pixelarium::lib::utilities_static
+  pixelarium::lib::imaging_static
+  pixelarium::lib::resources_static)
 
 # This needs to be public to let the consumer know about it.
 if(WIN32)
@@ -42,9 +79,12 @@ if(APPLE)
 endif()
 
 target_include_directories(${APPLIBNAME}
+  INTERFACE
   PRIVATE ${CMAKE_BINARY_DIR}
-  PRIVATE ${PROJECT_SOURCE_DIR}/lib
-  PRIVATE ${PROJECT_SOURCE_DIR}/lib/imaging
+  PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/rendering/include
+  PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include
   PUBLIC ${pfd_DIR}
   PUBLIC ${imgui_DIR}
-  PUBLIC ${imgui_DIR}/backends)
+  PUBLIC ${imgui_DIR}/misc/cpp
+  PUBLIC ${imgui_DIR}/backends
+  ${IMPLOT_DIR})

lib/app/DefaultApp.cpp

@@ -2,124 +2,45 @@
 
 #include <cstddef>
 #include <format>
-#include <memory>
 
+#include "ILog.hpp"
 #include "PixelariumImageFactory.hpp"
 #include "app_resources_default.h"
 #include "imgui.h"
 #include "portable-file-dialogs.h"
-#include "rendering/RenderImageManager.hpp"
-#include "resources/resource.hpp"
-#include "utilities/ILog.hpp"
+#include "resource.hpp"
 
 using namespace pixelarium::imaging;
+using namespace pixelarium::application;
 
-void pixelarium::ui::DefaultApp::MenuBarOptionsColumn1()
+void DefaultApp::MenuBarOptionsColumn1()
 {
     ImGui::MenuItem(SHOWIMGUIDEMOS, NULL, &this->demop_);
     ImGui::MenuItem(SHOWIMAGEGALLERY, NULL, &this->image_listp_);
 }
 
-void pixelarium::ui::DefaultApp::MenuBarOptionsColumn2()
+void DefaultApp::MenuBarOptionsColumn2()
 {
     if (ImGui::BeginMenu(FILEMENUNAME))
     {
         if (ImGui::MenuItem(LOADIMAGE))
         {
-            this->LoadImage();
+            this->LoadImageDialogue();
         }
 
         ImGui::EndMenu();
     }
 }
 
-void pixelarium::ui::DefaultApp::Run()
+void DefaultApp::Run()
 {
     if (demop_) ImGui::ShowDemoWindow(&this->demop_);
-    if (image_listp_) this->ImageGalleryRender();
+    if (image_listp_) this->gallery_.RenderGallery();
 
-    this->RenderImages();
+    this->gallery_.RenderImages();
 }
 
-void pixelarium::ui::DefaultApp::RenderImages()
-{
-    this->render_manager_->Enumerate(
-        [&](resources::ResourceKey key, render::RenderImageStateWrapper& render_state)
-        {
-            render_state.view->ShowImage();
-
-            if (!*render_state.view->GetStatus())
-            {
-                this->render_manager_->MarkForDeletion(key);
-            }
-        });
-}
-
-void pixelarium::ui::DefaultApp::ImageGalleryRender()
-{
-    ImGui::SetNextWindowSize(ImVec2(300, 550));
-    ImGui::Begin(SHOWIMAGEGALLERY, &this->image_listp_);
-
-    // this updates the render collection
-    // essentially deleting render views that were
-    // marked for deletion
-    this->render_manager_->UpdateCollection();
-
-    static size_t selected_index{0};
-    int highlight_index{-1};
-
-    if (ImGui::BeginListBox("Image List", ImVec2(200, 400)))
-    {
-        pool_.EnumerateResources(
-            [&](size_t id, size_t idx, const imaging::IPixelariumImage& img) -> void
-            {
-                const bool is_selected = selected_index == idx;
-                if (ImGui::Selectable(std::format("{}", img.Name()).c_str(), is_selected))
-                {
-                    selected_index = idx;
-                    this->selected_image_ = id;
-                }
-                if (highlight_index && ImGui::IsItemHovered()) highlight_index = idx;
-
-                if (is_selected) ImGui::SetItemDefaultFocus();
-            });
-
-        ImGui::EndListBox();
-    }
-
-    ImGui::Checkbox(AUTOSHOWSELECTED, &this->auto_show_selectd_image_);
-    ImGui::SameLine();  // put the button next to the checkbox
-    // note that the button will only show when the checkbox is toggled off
-    // this is intended behavior as the selected image will render automatically
-    // when the checkbox is toggled on
-    if (this->auto_show_selectd_image_ || ImGui::Button(OPENIMAGE))
-    {
-        // Try add the selected index to the manager
-        this->render_manager_->Add(this->selected_image_);
-    }
-
-    if (ImGui::Button(LOADIMAGE))
-    {
-        this->LoadImage();
-    }
-
-    if (ImGui::Button(REMOVEIMAGE))
-    {
-        this->render_manager_->MarkForDeletion(this->selected_image_);
-        this->pool_.DeleteResource(this->selected_image_);
-    }
-
-    ImGui::SameLine();
-    if (ImGui::Button(CLEARALL))
-    {
-        this->render_manager_->Clear();
-        this->pool_.Clear();
-    }
-
-    ImGui::End();  // end gallery window
-}
-
-void pixelarium::ui::DefaultApp::LoadImage()
+void DefaultApp::LoadImageDialogue()
 {
     auto res{pfd::open_file("Load Inputs", pfd::path::home(), {"All Files", "*"}, pfd::opt::multiselect).result()};
     for (auto& p : res)
@@ -128,7 +49,7 @@ void pixelarium::ui::DefaultApp::LoadImage()
 
         try
         {
-            pool_.SetResource(PixelariumImageFactory::CreateImage(p));
+            pool_.SetResource(PixelariumImageFactory::CreateImage(p, logger_));
         }
         catch (pixelarium::resources::empty_resource_exception& e)
         {

lib/app/DefaultApp.hpp

@@ -1,43 +0,0 @@
-#pragma once
-
-#include <cstddef>
-#include <memory>
-
-#include "AppGLFW.hpp"
-#include "imgui.h"
-#include "rendering/RenderImageManager.hpp"
-#include "resources/resource.hpp"
-#include "utilities/ILog.hpp"
-
-namespace pixelarium::ui
-{
-class DefaultApp : public application::AppGLFW
-{
-   public:
-    DefaultApp(const utils::log::ILog& log, pixelarium::resources::ImageResourcePool& pool)
-        : application::AppGLFW(log),
-          pool_(pool),
-          render_manager_(std::make_unique<render::RenderImageManager>(pool, log))
-    {
-    }
-
-   protected:
-    void MenuBarOptionsColumn1() override;
-    void MenuBarOptionsColumn2() override;
-    void Run() override;
-
-   private:
-    void LoadImage();
-    void ImageGalleryRender();
-    void RenderImages();
-
-   private:
-    resources::ImageResourcePool& pool_;
-    std::unique_ptr<render::RenderImageManager> render_manager_;
-    bool image_listp_{true};
-    bool auto_show_selectd_image_{true};
-    bool demop_{false};
-    ImVec2 curr_dim_;
-    size_t selected_image_{0};
-};
-}  // namespace pixelarium::ui

lib/app/PixelariumGallery.cpp

@@ -0,0 +1,86 @@
+#include "PixelariumGallery.hpp"
+
+#include <format>
+
+#include "app_resources_default.h"
+#include "imgui.h"
+
+using namespace pixelarium::application;
+
+void PixelariumImageGallery::RenderGallery()
+{
+    ImGui::SetNextWindowSize(ImVec2(300, 550));
+    ImGui::Begin(SHOWIMAGEGALLERY, &this->image_listp_);
+
+    // this updates the render collection
+    // essentially deleting render views that were
+    // marked for deletion
+    this->render_manager_->UpdateCollection();
+
+    static size_t selected_index{0};
+    int highlight_index{-1};
+
+    if (ImGui::BeginListBox("Image List", ImVec2(200, 400)))
+    {
+        pool_.EnumerateResources(
+            [&](size_t id, size_t idx, const imaging::IPixelariumImage<cv::Mat>& img) -> void
+            {
+                const bool is_selected = selected_index == idx;
+                if (ImGui::Selectable(std::format("{}", img.Name()).c_str(), is_selected))
+                {
+                    selected_index = idx;
+                    this->selected_image_ = id;
+                }
+                if (highlight_index && ImGui::IsItemHovered()) highlight_index = idx;
+
+                if (is_selected) ImGui::SetItemDefaultFocus();
+            });
+
+        ImGui::EndListBox();
+    }
+
+    ImGui::Checkbox(AUTOSHOWSELECTED, &this->auto_show_selectd_image_);
+    ImGui::SameLine();  // put the button next to the checkbox
+    // note that the button will only show when the checkbox is toggled off
+    // this is intended behavior as the selected image will render automatically
+    // when the checkbox is toggled on
+    if (this->auto_show_selectd_image_ || ImGui::Button(OPENIMAGE))
+    {
+        // Try add the selected index to the manager
+        this->render_manager_->Add(this->selected_image_);
+    }
+
+    if (ImGui::Button(LOADIMAGE))
+    {
+        this->load_image_();
+    }
+
+    if (ImGui::Button(REMOVEIMAGE))
+    {
+        this->render_manager_->MarkForDeletion(this->selected_image_);
+        this->pool_.DeleteResource(this->selected_image_);
+    }
+
+    ImGui::SameLine();
+    if (ImGui::Button(CLEARALL))
+    {
+        this->render_manager_->Clear();
+        this->pool_.Clear();
+    }
+
+    ImGui::End();  // end gallery window
+}
+
+void PixelariumImageGallery::RenderImages()
+{
+    this->render_manager_->Enumerate(
+        [&](resources::ResourceKey key, application::RenderImageStateWrapper& render_state)
+        {
+            render_state.view->ShowImage();
+
+            if (!*render_state.view->GetStatus())
+            {
+                this->render_manager_->MarkForDeletion(key);
+            }
+        });
+}

lib/app/app_resources_default.h.in

@@ -17,6 +17,9 @@
 #define LOADIMAGE           "Load Image"
 #define REMOVEIMAGE         "Remove Image"
 #define CLEARALL            "Clear All"
+#define SAVEAS              "Save As..."
 // clang-format on
 
 inline constexpr std::array<std::string_view, 5> LOGLEVELS = {"Trace", "Debug", "Info", "Warning", "Error"};
+
+inline constexpr auto kInitialWindowWidth {700.0f};

lib/app/include/AppGLFW.hpp

@@ -0,0 +1,80 @@
+#pragma once
+
+#include <GLFW/glfw3.h>
+
+#include <format>
+
+#include "ILog.hpp"
+#include "imgui_proxy.hpp"
+
+namespace pixelarium::application
+{
+/// @brief Base class providing scaffolding with GLFW and some default
+/// implementations that can be extended and/or overridden by consumers
+class AppGLFW
+{
+   public:
+    explicit AppGLFW(const utils::log::ILog& log) : logger_(log), plot_context_(ImPlot::CreateContext())
+    {
+        this->InitMainWindow();
+    }
+
+    ~AppGLFW() { ImPlot::DestroyContext(plot_context_); }
+
+    AppGLFW(AppGLFW&) = delete;
+    AppGLFW(const AppGLFW&) = delete;
+    AppGLFW(AppGLFW&&) = delete;
+    AppGLFW& operator=(AppGLFW&) = delete;
+    AppGLFW& operator=(AppGLFW&&) = delete;
+
+    /// @brief Start the main render loop
+    void Start() { this->RunLoop(); }
+
+    void SetStatusTimed(const std::string& status, size_t second);
+
+    void SetStatus(const std::string& status)
+    {
+        logger_.Info(std::format("{}(): {}", __PRETTY_FUNCTION__, status));
+        status_message_ = status;
+        show_status_ = true;
+    }
+
+    void ResetStatus()
+    {
+        status_message_.clear();
+        show_status_ = false;
+    }
+
+   protected:
+    /// @brief Function implementing the first column of the menu bar (e.g. "Menu")
+    virtual void MenuBarOptionsColumn1() {}
+
+    /// @brief Function implementing the second column of the menu bar (e.g. "File")
+    virtual void MenuBarOptionsColumn2() {}
+
+    /// @brief Function implementing the third column of the menu bar (e.g. "Options")
+    virtual void MenuBarOptionsColumn3() {}
+
+    /// @brief Function implementing the fourth column of the menu bar (e.g. "More")
+    virtual void MenuBarOptionsColumn4() {}
+
+    /// @brief Function implementing the first column of the menu bar (e.g. "Help")
+    virtual void MenuBarOptionsColumn5() {}
+
+    /// @brief Main function that gets called within the render loop.
+    virtual void Run() {}
+
+    const utils::log::ILog& logger_;
+
+   private:
+    int RunLoop();
+    void InitMainWindow();
+    void MenuBar();
+    void LogLevelSelect();
+    int log_level_{0};
+    GLFWwindow* window = nullptr;
+    ImPlotContext* plot_context_ = nullptr;
+    bool show_status_{false};
+    std::string status_message_{};
+};
+}  // namespace pixelarium::application

lib/app/include/DefaultApp.hpp

@@ -0,0 +1,42 @@
+#pragma once
+
+#include <cstddef>
+
+#include "AppGLFW.hpp"
+#include "ILog.hpp"
+#include "PixelariumGallery.hpp"
+#include "imgui_proxy.hpp"
+#include "resource.hpp"
+
+namespace pixelarium::application
+{
+/// @brief Default implementation of AppGLFW.
+/// This can either be used as is, as an example or as a base class
+/// providing some defaults for a more custom implementation.
+class DefaultApp : public AppGLFW
+{
+   public:
+    DefaultApp(const utils::log::ILog& log, pixelarium::resources::ImageResourcePool& pool)
+        : application::AppGLFW(log), pool_(pool), gallery_(log, pool)
+    {
+        gallery_.SetLoadFunction([&]() -> void { this->LoadImageDialogue(); });
+    }
+
+   protected:
+    void MenuBarOptionsColumn1() override;
+    void MenuBarOptionsColumn2() override;
+    void Run() override;
+
+   protected:
+    resources::ImageResourcePool& pool_;
+    application::PixelariumImageGallery gallery_;
+
+   protected:
+    void LoadImageDialogue();
+
+   private:
+    bool image_listp_{true};
+    bool demop_{false};
+    ImVec2 curr_dim_;
+};
+}  // namespace pixelarium::application

lib/app/include/PixelariumGallery.hpp

@@ -0,0 +1,58 @@
+#pragma once
+
+#include "ILog.hpp"
+#include "RenderImageManager.hpp"
+#include "resource.hpp"
+
+namespace pixelarium::application
+{
+
+/// @brief Defines a concept for a gallery type
+/// @tparam P  The resource pool type of the gallery concept
+template <typename P, class D>
+concept GalleryT = requires(P& p) { static_cast<resources::IResourcePool<P, D>&>(p); };
+
+/// @brief Interface for a Pixelarium gallery.
+///
+/// Defines generic functionality for a gallery of a specific
+/// resource type given by the template argument.
+/// @tparam GalleryT  The type of IResourcePool that the given implementation
+///                   provides a gallery for.
+template <typename GalleryT>
+class IPixelariumGallery
+{
+   public:
+    virtual ~IPixelariumGallery() = default;
+    virtual void RenderGallery() = 0;
+};
+
+/// @brief Implements IPixelariumGallery for a ImageResourcePool
+class PixelariumImageGallery : IPixelariumGallery<resources::ImageResourcePool>
+{
+    using Pool = resources::ImageResourcePool;
+    using Log = utils::log::ILog;
+
+   public:
+    PixelariumImageGallery(const Log& log, resources::ImageResourcePool& pool)
+        : pool_{pool}, log_{log}, render_manager_(std::make_unique<application::RenderImageManager>(pool, log))
+    {
+    }
+
+    void RenderGallery() override;
+
+    void RenderImages();
+
+    void Add(resources::ResourceKey key) { this->render_manager_->Add(key); }
+
+    void SetLoadFunction(const std::function<void()>& fun) { this->load_image_ = fun; };
+
+   private:
+    std::function<void()> load_image_{};
+    Pool& pool_;
+    const Log& log_;
+    std::unique_ptr<application::RenderImageManager> render_manager_;
+    bool image_listp_{true};
+    bool auto_show_selectd_image_{true};
+    size_t selected_image_{0};
+};
+}  // namespace pixelarium::application

lib/app/include/imgui_proxy.hpp

@@ -0,0 +1,5 @@
+#pragma once
+
+#include "imgui.h"
+#include "imgui_stdlib.h"
+#include "implot.h"

lib/app/rendering/CvMatRender.cpp

@@ -1,17 +1,15 @@
 #include "CvMatRender.hpp"
 
-#include <memory>
 #include <opencv2/core/mat.hpp>
 #include <opencv2/imgproc.hpp>
-#include <stdexcept>
 
-#include "imaging/IPixelariumImage.hpp"
+#include "IPixelariumImage.hpp"
 
 using namespace pixelarium::imaging;
 
 /// @brief Constructor for the CvMatRender class.
 /// @param img A shared pointer to the PixelariumImage to be rendered.
-pixelarium::render::CvMatRender::CvMatRender(std::shared_ptr<pixelarium::imaging::IPixelariumImage>& img) : base_(img), texture_(0)
+pixelarium::application::CvMatRender::CvMatRender(const cv::Mat& img) : base_(img), texture_(0)
 {
     // storing a copy of the to-be-rendered image
     // because it will be resized and filtered eventually which we absolutely
@@ -22,7 +20,7 @@ pixelarium::render::CvMatRender::CvMatRender(std::shared_ptr<pixelarium::imaging
 
 /// @brief Destructor for the CvMatRender class.
 /// Deallocates the OpenGL texture if it exists.
-pixelarium::render::CvMatRender::~CvMatRender()
+pixelarium::application::CvMatRender::~CvMatRender()
 {
     if (texture_)
     {
@@ -31,19 +29,10 @@ pixelarium::render::CvMatRender::~CvMatRender()
     }
 }
 
-/// @brief Resets the render image with a new PixelariumImage.
-/// @param img A shared pointer to the new PixelariumImage.
-void pixelarium::render::CvMatRender::ResetRenderImage(std::shared_ptr<pixelarium::imaging::IPixelariumImage>& img)
-{
-    this->base_ = img;
-    this->ResetRenderImage();
-    cv::cvtColor(this->img_, this->img_, cv::COLOR_BGR2RGBA);
-}
-
 /// @brief Uploads the current image data to an OpenGL texture.
 /// @return The ID of the uploaded OpenGL texture.
 /// @throws std::runtime_error if the image data is empty or if there is an OpenGL error.
-GLuint pixelarium::render::CvMatRender::uploadTexture()
+GLuint pixelarium::application::CvMatRender::uploadTexture()
 {
     if (img_.empty())
     {
@@ -66,21 +55,25 @@ GLuint pixelarium::render::CvMatRender::uploadTexture()
 
     const int width = img_.cols;
     const int height = img_.rows;
-
-    switch (img_.type()) {
+    // see
+    // https://stackoverflow.com/questions/10167534/how-to-find-out-what-type-of-a-mat-object-is-with-mattype-in-opencv
+    // for pixel a pixel type table
+    switch (img_.type())
+    {
+        case CV_8U:
+            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_BYTE, img_.data);
+            break;
         case CV_16U:
         case CV_16UC3:
-        case 26:
-            glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+        case CV_16UC4:
             glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_SHORT, img_.data);
             break;
-        case 5:
-        case 29:
-            glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
-            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_FLOAT, img_.data);
+        case CV_32F:
+        case CV_32FC4:
+            glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, width, height, 0, GL_DEPTH_COMPONENT, GL_FLOAT,
+                         img_.data);
             break;
         default:
-            glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
             glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, img_.cols, img_.rows, 0, GL_RGBA, GL_UNSIGNED_BYTE, img_.data);
             break;
     }
@@ -96,18 +89,14 @@ GLuint pixelarium::render::CvMatRender::uploadTexture()
 
 /// @brief Renders the image by uploading it as a texture.
 /// @return The ID of the OpenGL texture.
-GLuint pixelarium::render::CvMatRender::Render() { return this->uploadTexture(); }
+GLuint pixelarium::application::CvMatRender::Render() { return this->uploadTexture(); }
 
 /// @brief Renders the image with a specified scaling factor.
 /// @param factor The scaling factor for resizing the image.
 /// @return The ID of the OpenGL texture.
-GLuint pixelarium::render::CvMatRender::Render(float factor)
+GLuint pixelarium::application::CvMatRender::Render(float factor)
 {
-    auto res_val {this->base_->TryGetImage()};
-    if (res_val)
-    {
-        cv::resize(*res_val, this->img_, cv::Size(0, 0), factor, factor, cv::INTER_LINEAR_EXACT);
-    }
+    cv::resize(this->base_, this->img_, cv::Size(0, 0), factor, factor, cv::INTER_LINEAR_EXACT);
 
     return this->uploadTexture();
 }
@@ -116,16 +105,9 @@ GLuint pixelarium::render::CvMatRender::Render(float factor)
 /// @param width The maximum width of the rendered image.
 /// @param height The maximum height of the rendered image.
 /// @return The ID of the OpenGL texture.
-GLuint pixelarium::render::CvMatRender::Render(size_t width, size_t height)
+GLuint pixelarium::application::CvMatRender::Render(size_t width, size_t height)
 {
-    auto res_val {this->base_->TryGetImage()};
-
-    if (!res_val)
-    {
-        return this->Render(1.0f);
-    }
-
-    const auto sz{res_val->size()};
+    const auto sz{this->base_.size()};
 
     const auto get_factor = [](auto opt1, auto opt2) -> float { return opt1 < opt2 ? opt1 : opt2; };
 
@@ -134,20 +116,8 @@ GLuint pixelarium::render::CvMatRender::Render(size_t width, size_t height)
     return this->Render(factor);
 }
 
-void pixelarium::render::CvMatRender::ResetRenderImage()
+void pixelarium::application::CvMatRender::ResetRenderImage()
 {
-    if (this->base_ == nullptr)
-    {
-        return;
-    }
-
-    auto root_res = this->base_->TryGetImage();
-
-    if (!root_res)
-    {
-        return;
-    }
-
     // we copy here
-    this->img_ = root_res->clone();
+    this->img_ = this->base_.clone();
 }

lib/app/rendering/IPixelariumImageView.cpp

@@ -0,0 +1,34 @@
+#include "IPixelariumImageView.hpp"
+
+#include <opencv2/imgcodecs.hpp>
+
+#include "app_resources_default.h"
+#include "imgui.h"
+#include "portable-file-dialogs.h"
+
+auto pixelarium::application::IPixelariumImageView::ImageViewMenuBar() -> void
+{
+    if (ImGui::BeginMenuBar())
+    {
+        if (ImGui::BeginMenu("File"))
+        {
+            if (ImGui::MenuItem(SAVEAS))
+            {
+                auto dest = pfd::save_file("Save File", ".", {"Image Files", "*.png *.jpg *.jpeg *.tiff"},
+                                           pfd::opt::force_overwrite)
+                                .result();
+                if (!dest.empty())
+                {
+                    // this->img_->SaveImage(dest);
+                    cv::imwrite(dest, cached_image_);
+                }
+            }
+
+            ImageViewMenuBarAdditions();
+
+            ImGui::EndMenu();
+        }
+
+        ImGui::EndMenuBar();
+    }
+}

lib/app/rendering/ImageViewFactory.cpp

@@ -0,0 +1,74 @@
+#include "ImageViewFactory.hpp"
+
+#include <format>
+#include <memory>
+
+#include "IPixelariumImage.hpp"
+#include "IPixelariumImageView.hpp"
+#include "PixelariumImageFactory.hpp"
+#include "PixelariumImageViewCzi.hpp"
+#include "PixelariumImageViewDefault.hpp"
+
+/// @brief Creates a PixelariumImageView from a resource image.
+/// @param image_id The ID of the image resource to render.
+/// @return A unique pointer to the PixelariumImageView, or nullptr if the image resource is not found or is empty.  The
+/// image data is copied.
+std::unique_ptr<pixelarium::application::IPixelariumImageView> pixelarium::application::ImageViewFactory::RenderImage(
+    resources::ResourceKey image_id)
+{
+    using ImageType = imaging::ImageFileType;
+    auto res{this->image_pool_.GetResource(image_id)};
+
+    const auto img{res.lock()};
+
+    if (img == nullptr)
+    {
+        return {};
+    }
+
+    if (img->Empty())
+    {
+        return {};
+    }
+
+    auto type = imaging::ExtensionToType(img->Uri().extension().string());
+    if (img->Uri().empty())
+    {
+        log_.Info(std::format("{}: empty Uri for {}.", __PRETTY_FUNCTION__, img->Name()));
+        type = ImageType::kMemory;
+    }
+
+    switch (type)
+    {
+        case ImageType::kUnknown:
+        case ImageType::kAbstract:
+        case ImageType::kPng:
+        case ImageType::kJpg:
+        case ImageType::kTiff:
+        case ImageType::kMemory:
+            log_.Info(std::format("{}: Creating a Default View", __PRETTY_FUNCTION__));
+            // beware: here we copy the actual image resource over to the new image
+            try
+            {
+                auto view{std::make_unique<PixelariumImageViewDefault>(img)};
+                return view;
+            }
+            catch (const std::exception& ex)
+            {
+                log_.Error(std::format("{}: Creating view failed: {}", __PRETTY_FUNCTION__, ex.what()));
+            }
+        case ImageType::kCzi:
+            log_.Info(std::format("{}: Creating a CZI View", __PRETTY_FUNCTION__));
+            try
+            {
+                auto view{std::make_unique<PixelariumImageViewCzi>(img, log_)};
+                return view;
+            }
+            catch (const std::exception& ex)
+            {
+                log_.Error(std::format("{}: Creating view failed: {}", __PRETTY_FUNCTION__, ex.what()));
+            }
+        default:
+            return {};
+    }
+}

lib/app/rendering/PixelariumImageViewCzi.cpp

@@ -0,0 +1,133 @@
+#include "PixelariumImageViewCzi.hpp"
+
+#include <format>
+#include <memory>
+#include <stdexcept>
+
+#include "CvMatRender.hpp"
+#include "IPixelariumImage.hpp"
+#include "PixelariumCzi.hpp"
+#include "RenderHelpers.hpp"
+#include "imgui.h"
+
+void pixelarium::application::PixelariumImageViewCzi::RefreshCachedImage()
+{
+    if (this->cached_image_.empty() || this->is_dirty_)
+    {
+        log_.Info(std::format("{}: refreshing image.", __PRETTY_FUNCTION__));
+        imaging::CziParams params;
+        params.dimension_map = this->dimension_map_;
+        this->cached_image_ = this->img_->TryGetImage(params).value_or(cv::Mat{});
+        // Resetting the image while the renderer is possibly accessing the
+        // image at the same time is not a good idea. Therefore, we simply create
+        // a new renderer here.
+        this->render_ = std::make_unique<CvMatRender>(this->cached_image_);
+        this->is_dirty_ = false;
+    }
+}
+
+pixelarium::application::PixelariumImageViewCzi::PixelariumImageViewCzi(std::shared_ptr<Image> img, const Log& log)
+    : log_(log)
+{
+    img_ = img;
+    auto czi_img = std::static_pointer_cast<imaging::PixelariumCzi>(this->img_);
+
+    auto stats = czi_img->GetStatistics();
+    stats.dimBounds.EnumValidDimensions(
+        [&](libCZI::DimensionIndex dim, int start, int) -> bool
+        {
+            this->dimension_map_[dim] = start;
+            return true;
+        });
+
+    auto render_mat = img->TryGetImage();
+    if (render_mat.has_value())
+    {
+        this->render_ = std::make_unique<CvMatRender>(render_mat.value());
+    }
+    else
+    {
+        auto msg{std::format("{}: fetching image failed: {}", __PRETTY_FUNCTION__, img->Name())};
+        log_.Error(msg);
+        throw std::runtime_error(msg);
+    }
+
+    // this->SetInitialSize();
+    log_.Info(std::format("{}: dimension map size: {}", __PRETTY_FUNCTION__, dimension_map_.size()));
+}
+
+/// @brief Displays the image in an ImGui window.
+///
+/// If the image is null, empty, or has an empty name, the function returns immediately.  Otherwise, it creates an ImGui
+/// window with a horizontal scrollbar and menu bar. The image is rendered using the CvMatRender object, resizing it to
+/// fit the available window space.  The raw and rendered dimensions are displayed below the image.
+void pixelarium::application::PixelariumImageViewCzi::ShowImage()
+{
+    auto czi_img = std::static_pointer_cast<imaging::PixelariumCzi>(this->img_);
+
+    if (!czi_img) return;
+
+    RefreshCachedImage();
+
+    if (czi_img->Empty() || this->img_->type_ == imaging::ImageFileType::kUnknown || cached_image_.empty() ||
+        czi_img->Name().empty())
+    {
+        // do nothing
+        return;
+    }
+
+    if (first_render_)
+    {
+        first_render_ = false;
+        constexpr auto initial_width{700.0f};
+        const auto cached_width{cached_image_.cols};
+        const auto cached_heigth{cached_image_.rows};
+        const auto ratio{static_cast<float>(cached_heigth) / cached_width};
+        SetInitialSize(initial_width, (initial_width * ratio + 100));
+    }
+
+    ImGui::Begin(this->img_->Name().c_str(), &this->open_p,
+                 ImGuiWindowFlags_HorizontalScrollbar | ImGuiWindowFlags_MenuBar);
+
+    ImageViewMenuBar();
+
+    this->curr_dim_ = ImGui::GetContentRegionAvail();
+    auto new_dim = ImGui::GetContentRegionAvail();
+    auto texture =
+        dim_changed_p(this->curr_dim_, new_dim)
+            ? this->render_->Render(static_cast<size_t>(this->curr_dim_.x), static_cast<size_t>(this->curr_dim_.y))
+            : this->render_->Render();
+
+    this->curr_dim_ = new_dim;
+
+    ImVec2 dim(cached_image_.cols, cached_image_.rows);
+
+    ImGui::Image(reinterpret_cast<ImTextureID>(reinterpret_cast<void*>(texture)),
+                 aspect_const_dimensions(dim, new_dim));
+
+    ImGui::Separator();
+    ImGui::Text("%s", std::format("   Raw Dimensions W : {}, H: {}", dim.x, dim.y).c_str());
+    ImGui::Text("%s", std::format("Render Dimensions W : {}, H: {}", curr_dim_.x, curr_dim_.y).c_str());
+    ImGui::Text("Dimensions");
+    ImGui::Separator();
+    if (ImGui::Button("Update"))
+    {
+        this->ForceUpdate();
+    }
+
+    auto stats = czi_img->GetStatistics();
+    stats.dimBounds.EnumValidDimensions(
+        [&](libCZI::DimensionIndex dim, int start, int size) -> bool
+        {
+            auto dim_char = libCZI::Utils::DimensionToChar(dim);
+            if (ImGui::SliderInt(std::format("{}({}-{})", dim_char, start, size).c_str(), &dimension_map_[dim], start,
+                                 size - 1))
+            {
+                this->ForceUpdate();
+            }
+
+            return true;
+        });
+
+    ImGui::End();
+}

lib/app/rendering/PixelariumImageViewDefault.cpp

@@ -0,0 +1,145 @@
+#include "PixelariumImageViewDefault.hpp"
+
+#include <opencv2/core/hal/interface.h>
+
+#include <cstdio>
+#include <format>
+#include <iostream>
+#include <opencv2/core.hpp>
+#include <opencv2/imgproc.hpp>
+#include <ostream>
+#include <ranges>
+#include <utility>
+
+#include "IPixelariumImage.hpp"
+#include "RenderHelpers.hpp"
+#include "app_resources_default.h"
+#include "imgui.h"
+#include "implot.h"
+#include "simple_thread_pool.hpp"
+
+void pixelarium::application::PixelariumImageViewDefault::RefreshCachedImage()
+{
+    if (this->cached_image_.empty() || this->is_dirty_)
+    {
+        this->cached_image_ = this->img_->TryGetImage().value_or(cv::Mat{});
+        this->is_dirty_ = false;
+    }
+}
+
+void pixelarium::application::PixelariumImageViewDefault::ImageViewMenuBarAdditions()
+{
+    ImGui::MenuItem("Histogram", NULL, &this->show_hists_);
+}
+
+/// @brief Displays the image in an ImGui window.
+///
+/// If the image is null, empty, or has an empty name, the function returns immediately.  Otherwise, it creates an ImGui
+/// window with a horizontal scrollbar and menu bar. The image is rendered using the CvMatRender object, resizing it to
+/// fit the available window space.  The raw and rendered dimensions are displayed below the image.
+void pixelarium::application::PixelariumImageViewDefault::ShowImage()
+{
+    RefreshCachedImage();
+
+    if (this->img_->Empty() || this->img_->type_ == imaging::ImageFileType::kUnknown || this->cached_image_.empty() ||
+        this->img_->Name().empty())
+    {
+        // do nothing
+        return;
+    }
+
+    if (first_render_)
+    {
+        first_render_ = false;
+
+        const auto cached_width{cached_image_.cols};
+        const auto cached_heigth{cached_image_.rows};
+        const auto ratio{static_cast<float>(cached_heigth) / cached_width};
+        SetInitialSize(kInitialWindowWidth, (kInitialWindowWidth * ratio + 100));
+        utils::pixelarium_pool::enqueue([this]() { GenerateHistogram(); });
+    }
+
+    ImGui::Begin(this->img_->Name().c_str(), &this->open_p,
+                 ImGuiWindowFlags_HorizontalScrollbar | ImGuiWindowFlags_MenuBar);
+
+    ImageViewMenuBar();
+
+    this->curr_dim_ = ImGui::GetContentRegionAvail();
+    auto new_dim = ImGui::GetContentRegionAvail();
+    auto texture =
+        dim_changed_p(this->curr_dim_, new_dim)
+            ? this->render_.Render(static_cast<size_t>(this->curr_dim_.x), static_cast<size_t>(this->curr_dim_.y))
+            : this->render_.Render();
+
+    this->curr_dim_ = new_dim;
+
+    ImVec2 dim(cached_image_.cols, cached_image_.rows);
+
+    ImGui::Image(reinterpret_cast<ImTextureID>(reinterpret_cast<void*>(texture)),
+                 aspect_const_dimensions(dim, new_dim));
+
+    ImGui::Separator();
+
+    if (show_hists_ && hist_available_)
+    {
+        if (ImPlot::BeginPlot("Histogram"))
+        {
+            ImPlot::SetupAxes(nullptr, nullptr, ImPlotAxisFlags_AutoFit, ImPlotAxisFlags_AutoFit);
+            using style_pair = std::pair<const char*, ImVec4>;
+
+            constexpr std::array<style_pair, 3> names = {
+                {{"Blue", ImVec4(0, 0, 1, 1)}, {"Green", ImVec4(0, 1, 0, 1)}, {"Red", ImVec4(1, 0, 0, 1)}}};
+            // for (auto& e : hist_planes_)
+            // {
+            //     ImPlot::PlotHistogram(name.c_str(), e.data, e.rows * e.cols, 16);
+            //     for (auto& e : name)
+            //     {
+            //         e++;
+            //     }
+            // }
+            for (size_t i{0}; i < hist_planes_.size(); ++i)
+            {
+                if (hist_planes_.at(i).type() == CV_32F)
+                {
+                    // ImPlot::PlotHistogram(names.at(i % 3), reinterpret_cast<float*>(hist_planes_[i].data),
+                    //                       hist_planes_[i].rows * hist_planes_[i].cols, 16, 1.0, ImPlotRange(),
+                    //                       ImPlotHistogramFlags_Horizontal);
+                    ImPlot::PushStyleColor(ImPlotCol_Line, names.at(i % 3).second);
+                    ImPlot::PlotLine(std::format("{}-line", names.at(i % 3).first).c_str(),
+                                     reinterpret_cast<float*>(hist_planes_[i].data),
+                                     hist_planes_[i].rows * hist_planes_[i].cols);
+                    ImPlot::PopStyleColor();
+                }
+            }
+
+            ImPlot::PushStyleVar(ImPlotStyleVar_FillAlpha, 0.25f);
+            ImPlot::SetNextMarkerStyle(ImPlotMarker_Square, 6, ImPlot::GetColormapColor(1), IMPLOT_AUTO,
+                                       ImPlot::GetColormapColor(1));
+
+            ImPlot::EndPlot();
+        }
+    }
+
+    ImGui::Text("%s", std::format("   Raw Dimensions W : {}, H: {}", dim.x, dim.y).c_str());
+    ImGui::Text("%s", std::format("Render Dimensions W : {}, H: {}", curr_dim_.x, curr_dim_.y).c_str());
+
+    ImGui::End();
+}
+
+auto pixelarium::application::PixelariumImageViewDefault::GenerateHistogram() -> void
+{
+    cv::split(cached_image_, bgr_planes_);
+    hist_planes_.resize(bgr_planes_.size());
+
+    int histSize = 256;
+    float range[] = {0, 256};  // the upper boundary is exclusive
+    const float* histRange[] = {range};
+
+    for (auto [bgr, hist] : std::ranges::views::zip(bgr_planes_, hist_planes_))
+    {
+        cv::calcHist(&bgr, 1, 0, cv::Mat(), hist, 1, &histSize, histRange, true, false);
+        // cv::normalize(hist, hist);
+    }
+
+    hist_available_ = true;
+}

lib/app/rendering/RenderHelpers.cpp

@@ -1,12 +1,13 @@
 #include "RenderHelpers.hpp"
 
 #include <cstdlib>
+
 /// @brief Checks if the dimensions of two ImVec2 vectors have changed significantly.
 /// @param ref_rect The reference ImVec2 vector.
 /// @param new_rect The new ImVec2 vector to compare against.
 /// @return True if the absolute difference between the y-coordinates is greater than 5 or the x-coordinates are
 /// different; otherwise, false.
-bool pixelarium::render::dim_changed_p(const ImVec2& ref_rect, const ImVec2& new_rect)
+bool pixelarium::application::dim_changed_p(const ImVec2& ref_rect, const ImVec2& new_rect)
 {
     if (std::abs(ref_rect.y - new_rect.y) > 5 || std::abs(ref_rect.x - new_rect.x))
     {
@@ -20,7 +21,7 @@ bool pixelarium::render::dim_changed_p(const ImVec2& ref_rect, const ImVec2& new
 /// @param img The input image.
 /// @param curr_dim The current dimensions.
 /// @return The calculated dimensions maintaining aspect ratio.
-ImVec2 pixelarium::render::aspect_const_dimensions(const ImVec2& raw_dim, const ImVec2& curr_dim)
+ImVec2 pixelarium::application::aspect_const_dimensions(const ImVec2& raw_dim, const ImVec2& curr_dim)
 {
     const auto w_fact = (curr_dim.x / raw_dim.x);
     const auto h_fact = (curr_dim.y / raw_dim.y);

lib/app/rendering/RenderImageManager.cpp

@@ -7,7 +7,7 @@ using namespace std;
 /// @brief Updates the collection of rendered images by removing images marked for deletion.
 /// This function iterates through the \c keys_to_delete_ list and removes the corresponding images from the collection.
 /// It does not acquire the mutex to avoid deadlocks with the `Remove` function.
-void pixelarium::render::RenderImageManager::UpdateCollection()
+void pixelarium::application::RenderImageManager::UpdateCollection()
 {
     for (const auto& key : keys_to_delete_)
     {
@@ -19,7 +19,7 @@ void pixelarium::render::RenderImageManager::UpdateCollection()
 
 /// @brief Marks a resource for deletion.
 /// @param key The ID of the resource to mark for deletion.
-void pixelarium::render::RenderImageManager::MarkForDeletion(resources::ResourceKey key)
+void pixelarium::application::RenderImageManager::MarkForDeletion(resources::ResourceKey key)
 {
     this->log_.Debug(std::format("{} marking key: \"{}\" for deletion.", __PRETTY_FUNCTION__, key));
     lock_guard<mutex> guard(this->mut_);
@@ -29,7 +29,7 @@ void pixelarium::render::RenderImageManager::MarkForDeletion(resources::Resource
 /// @brief Removes a render image from the manager.
 /// @param key The key of the render image to remove.
 /// @return True if the render image was removed, false otherwise.
-bool pixelarium::render::RenderImageManager::Remove(resources::ResourceKey key) noexcept
+bool pixelarium::application::RenderImageManager::Remove(resources::ResourceKey key) noexcept
 {
     bool remove_state{false};
     this->log_.Debug(std::format("{} removing key: \"{}\" from renderlist.", __PRETTY_FUNCTION__, key));
@@ -44,16 +44,24 @@ bool pixelarium::render::RenderImageManager::Remove(resources::ResourceKey key)
 /// @brief Adds a resource to the render image map.
 /// @param key The ID of the resource to add.
 /// @return void.  No exception is thrown.
-void pixelarium::render::RenderImageManager::Add(resources::ResourceKey key) noexcept
+void pixelarium::application::RenderImageManager::Add(resources::ResourceKey key) noexcept
 {
-    // we don't want to add what's already there
-    // or empty render images
-    auto current_view = this->view_factory_->RenderImage(key);
-    if (this->render_image_map_.contains(key) || current_view == nullptr)
+    // we don't want to add what's already there, render empty images, or failed keys
+    if (this->render_image_map_.contains(key)
+        // || this->failed_keys_cache_.contains(key)
+    )
     {
         return;
     }
 
+    auto current_view = this->view_factory_->RenderImage(key);
+    if (current_view == nullptr)
+    {
+        // failed to create view, cache this key to avoid repeated attempts
+        this->failed_keys_cache_.insert(key);
+        return;
+    }
+
     this->log_.Debug(std::format("{}: adding key: \"{}\" to renderlist.", __PRETTY_FUNCTION__, key));
 
     lock_guard<mutex> guard(this->mut_);
@@ -72,4 +80,4 @@ void pixelarium::render::RenderImageManager::Add(resources::ResourceKey key) noe
 
 /// @brief Clears all render images from the manager.
 /// @note This function is noexcept.
-void pixelarium::render::RenderImageManager::Clear() noexcept { this->render_image_map_.clear(); }
+void pixelarium::application::RenderImageManager::Clear() noexcept { this->render_image_map_.clear(); }

lib/app/rendering/include/CvMatRender.hpp

@@ -2,7 +2,6 @@
 // windows.h must come before GL/GL.h here.
 // clang format would change this, effectively rendering the build broken.
 // clang-format off
-#include <memory>
 #ifdef _WIN32
 #include <windows.h>
 #include <GL/GL.h>
@@ -13,11 +12,12 @@
 #endif
 #include <GLFW/glfw3.h>  // Will drag system OpenGL headers
 #endif
-#include "imaging/IPixelariumImage.hpp"
+#include <opencv2/core/mat.hpp>
 // clang-format on
 
-namespace pixelarium::render
+namespace pixelarium::application
 {
+/// @brief Renders cv::Mat bitmaps as OpenGL textures.
 class CvMatRender
 {
    public:
@@ -26,28 +26,27 @@ class CvMatRender
     // get removed in the future)
     // as the using AppGLFW constructs it empty as a member
     // when coming to life.
-    CvMatRender() = default;
+    // CvMatRender() = default;
     CvMatRender(CvMatRender&) = delete;
     CvMatRender(const CvMatRender&) = delete;
     CvMatRender(CvMatRender&&) = delete;
-    CvMatRender& operator=(CvMatRender&) = default;
-    CvMatRender& operator=(CvMatRender&& other) = default;
+    CvMatRender& operator=(CvMatRender&) = delete;
+    CvMatRender& operator=(CvMatRender&& other) = delete;
     ~CvMatRender();
-    explicit CvMatRender(std::shared_ptr<pixelarium::imaging::IPixelariumImage>& img);
+    explicit CvMatRender(const cv::Mat& img);
 
    public:
     GLuint Render();
     GLuint Render(float factor);
     GLuint Render(size_t width, size_t height);
     void ResetRenderImage();
-    void ResetRenderImage(std::shared_ptr<pixelarium::imaging::IPixelariumImage>& img);
 
    private:
     cv::Mat img_;
-    std::shared_ptr<pixelarium::imaging::IPixelariumImage> base_;
+    const cv::Mat& base_;
     GLuint texture_;
 
     GLuint uploadTexture();
 };
 
-}  // namespace pixelarium::render
+}  // namespace pixelarium::application

lib/app/rendering/include/IPixelariumImageView.hpp

@@ -0,0 +1,41 @@
+#pragma once
+
+#include <memory>
+
+#include "IPixelariumImage.hpp"
+#include "imgui.h"
+
+namespace pixelarium::application
+{
+/// @brief An interface defining the contract on views to dedicated implementations of IPixelariumImage
+class IPixelariumImageView
+{
+   public:
+    virtual ~IPixelariumImageView() = default;
+    virtual void ShowImage() = 0;
+
+    // default implemented
+   public:
+    virtual const bool* GetStatus() const noexcept { return &this->open_p; }
+    virtual void ForceUpdate() noexcept { this->is_dirty_ = true; }
+
+    // this must be called immediately before a "ImGui::Begin" context
+    // as it will affect the next window and result in undeterministic effects
+    // when called "out of sync"
+    virtual void SetInitialSize(float width = 700.0f, float height = 700.0f)
+    {
+        ImGui::SetNextWindowSize({width, height});
+    }
+
+   protected:
+    virtual void ImageViewMenuBar();
+    virtual void ImageViewMenuBarAdditions() {};
+
+   protected:
+    std::shared_ptr<imaging::IPixelariumImageCvMat> img_{};
+    cv::Mat cached_image_{};
+    bool open_p{true};
+    bool is_dirty_{true};
+    bool first_render_{true};
+};
+}  // namespace pixelarium::application

lib/app/rendering/include/ImageViewFactory.hpp

@@ -0,0 +1,25 @@
+#pragma once
+
+#include "ILog.hpp"
+#include "IPixelariumImageView.hpp"
+#include "resource.hpp"
+
+namespace pixelarium::application
+{
+/// @brief Factory for instantiating matching views to different implementations of IPixelariumImage.
+class ImageViewFactory
+{
+    using Image = imaging::IPixelariumImageCvMat;
+    using Pool = resources::ImageResourcePool;
+    using Log = utils::log::ILog;
+
+   public:
+    explicit ImageViewFactory(Pool& pool, const Log& log) : image_pool_(pool), log_(log) {}
+
+    std::unique_ptr<IPixelariumImageView> RenderImage(resources::ResourceKey id);
+
+   private:
+    Pool& image_pool_;
+    const Log& log_;
+};
+}  // namespace pixelarium::application

lib/app/rendering/include/PixelariumImageViewCzi.hpp

@@ -0,0 +1,41 @@
+#pragma once
+
+#include <memory>
+#include <unordered_map>
+
+#include "CvMatRender.hpp"
+#include "ILog.hpp"
+#include "IPixelariumImage.hpp"
+#include "IPixelariumImageView.hpp"
+#include "imgui.h"
+#include "libCZI_DimCoordinate.h"
+
+namespace pixelarium::application
+{
+/// @brief A CZI-specific implementation of IPixelariumImageView.
+class PixelariumImageViewCzi : public IPixelariumImageView
+{
+    using Image = imaging::IPixelariumImageCvMat;
+    using Log = utils::log::ILog;
+
+   public:
+    explicit PixelariumImageViewCzi(std::shared_ptr<Image> img, const Log& log);
+    PixelariumImageViewCzi() = delete;
+    PixelariumImageViewCzi(PixelariumImageViewCzi&) = delete;
+    PixelariumImageViewCzi(const PixelariumImageViewCzi&) = delete;
+    PixelariumImageViewCzi(PixelariumImageViewCzi&&) = delete;
+    PixelariumImageViewCzi& operator=(PixelariumImageViewCzi&) = delete;
+    PixelariumImageViewCzi& operator=(PixelariumImageViewCzi&&) = delete;
+
+    void ShowImage() override;
+
+   private:
+    ImVec2 curr_dim_{};
+    const Log& log_;
+    std::unordered_map<libCZI::DimensionIndex, int> dimension_map_;
+    std::unique_ptr<CvMatRender> render_;
+
+   private:
+    void RefreshCachedImage();
+};
+}  // namespace pixelarium::application

lib/app/rendering/include/PixelariumImageViewDefault.hpp

@@ -0,0 +1,46 @@
+#pragma once
+
+#include <memory>
+#include <vector>
+
+#include "CvMatRender.hpp"
+#include "IPixelariumImage.hpp"
+#include "IPixelariumImageView.hpp"
+#include "imgui.h"
+
+namespace pixelarium::application
+{
+/// @brief A default implementation of IPixelariumImageView.
+/// This is sufficient for single dimension images like png or jpg.
+class PixelariumImageViewDefault : public IPixelariumImageView
+{
+    using Image = imaging::IPixelariumImageCvMat;
+
+   public:
+    explicit PixelariumImageViewDefault(std::shared_ptr<Image> img) : render_(*img->TryGetImage()) { img_ = img; }
+
+    PixelariumImageViewDefault() = delete;
+    PixelariumImageViewDefault(PixelariumImageViewDefault&) = delete;
+    PixelariumImageViewDefault(const PixelariumImageViewDefault&) = delete;
+    PixelariumImageViewDefault(PixelariumImageViewDefault&&) = delete;
+    PixelariumImageViewDefault& operator=(PixelariumImageViewDefault&) = delete;
+    PixelariumImageViewDefault& operator=(PixelariumImageViewDefault&&) = delete;
+
+    void ShowImage() override;
+
+    void ImageViewMenuBarAdditions() override;
+
+    void GenerateHistogram();
+
+   private:
+    ImVec2 curr_dim_{};
+    CvMatRender render_;
+    bool show_hists_{false};
+    bool hist_available_{false};
+    std::vector<cv::Mat> bgr_planes_;
+    std::vector<cv::Mat> hist_planes_;
+
+   private:
+    void RefreshCachedImage();
+};
+}  // namespace pixelarium::application

lib/app/rendering/include/RenderHelpers.hpp

@@ -2,9 +2,9 @@
 
 #include "imgui.h"
 
-namespace pixelarium::render
+namespace pixelarium::application
 {
 bool dim_changed_p(const ImVec2& ref_rect, const ImVec2& new_rect);
 
 ImVec2 aspect_const_dimensions(const ImVec2& raw_dim, const ImVec2& curr_dim);
-};  // namespace pixelarium::render
+};  // namespace pixelarium::application

lib/app/rendering/include/RenderImageManager.hpp

@@ -4,15 +4,14 @@
 #include <unordered_map>
 #include <unordered_set>
 
+#include "ILog.hpp"
+#include "IPixelariumImageView.hpp"
 #include "ImageViewFactory.hpp"
-#include "PixelariumImageViewDefault.hpp"
-#include "rendering/IPixelariumImageView.hpp"
-#include "resources/resource.hpp"
-#include "utilities/ILog.hpp"
+#include "resource.hpp"
 
 // This is intended as an additional abstraction
 // aggregating views that should be rendered (or not)
-namespace pixelarium::render
+namespace pixelarium::application
 {
 /// @brief Instead of directly using the view, we
 /// proxy it through a wrapper. This allows for arbitrary additional data
@@ -23,6 +22,13 @@ struct RenderImageStateWrapper
     const bool* show_state;
 };
 
+/// @brief Manage instances of IPixelariumImageView.
+///
+/// This class is used to keep track of what must be rendered.
+/// It manages a set of IPixelariumImageView instances that can be traversed
+/// via its Enumerate() function.
+/// Views that shall not be rendered anymore should be marked for deletion
+/// with MarkForDeletion()
 class RenderImageManager
 {
     using Pool = resources::ImageResourcePool;
@@ -62,7 +68,8 @@ class RenderImageManager
     std::unique_ptr<ImageViewFactory> view_factory_;
     std::mutex mut_;
     std::unordered_set<resources::ResourceKey> keys_to_delete_;
+    std::unordered_set<resources::ResourceKey> failed_keys_cache_;
 
     const utils::log::ILog& log_;
 };
-}  // namespace pixelarium::render
+}  // namespace pixelarium::application

lib/imaging/CMakeLists.txt

@@ -1,4 +1,4 @@
-include(${CMAKE_SOURCE_DIR}/cmake/libCZI.cmake)
+include(libCZI)
 
 find_package(OpenCV REQUIRED)
 
@@ -6,15 +6,20 @@ message(STATUS "Found opencv: " ${OpenCV_INCLUDE_DIRS})
 message(STATUS "OpenCV_LIBs from: " ${OpenCV_LIBS})
 
 set(IMAGELIBSRC
-  IPixelariumImage.hpp
-  PixelariumImageFactory.hpp
+  include/IPixelariumImage.hpp
+  include/PixelariumImageFactory.hpp
+  impl/include/PixelariumJpg.hpp
+  impl/include/PixelariumPng.hpp
+  impl/include/PixelariumCzi.hpp
+  impl/include/PixelariumTiff.hpp
+  impl/include/PixelariumMem.hpp
+  IPixelariumImage.cpp
   PixelariumImageFactory.cpp
-  impl/PixelariumJpg.hpp
   impl/PixelariumJpg.cpp
-  impl/PixelariumPng.hpp
   impl/PixelariumPng.cpp
-  impl/PixelariumCzi.hpp
   impl/PixelariumCzi.cpp
+  impl/PixelariumTiff.cpp
+  impl/PixelariumMem.cpp
 )
 
 set(IMAGELIBLIBNAME pixelariumimagelib)
@@ -22,11 +27,19 @@ set(IMAGELIBLIBNAME pixelariumimagelib)
 add_library(${IMAGELIBLIBNAME}
   STATIC ${IMAGELIBSRC})
 
+add_library(pixelarium::lib::imaging_static ALIAS ${IMAGELIBLIBNAME})
+
+target_compile_definitions(${IMAGELIBLIBNAME} PUBLIC _LIBCZISTATICLIB)
+
 target_link_libraries(${IMAGELIBLIBNAME}
   PUBLIC ${OpenCV_LIBS}
+  PUBLIC pixelarium::lib::utilities_static
   PRIVATE libCZIStatic)
 
 
 target_include_directories(${IMAGELIBLIBNAME}
+  INTERFACE
+  PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include
+  PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/impl/include
   PUBLIC ${OpenCV_INCLUDE_DIRS}
   PUBLIC ${LIBCZI_INCLUDE_DIR})

lib/imaging/IPixelariumImage.cpp

@@ -0,0 +1,15 @@
+#include "IPixelariumImage.hpp"
+
+#include <opencv2/imgcodecs.hpp>
+
+bool pixelarium::imaging::IPixelariumImageCvMat::SaveImage(const std::string& uri)
+{
+    auto current_image = this->TryGetImage();
+
+    if (!current_image.has_value())
+    {
+        return false;
+    }
+
+    return cv::imwrite(uri, current_image.value());
+}

lib/imaging/IPixelariumImage.hpp

@@ -1,90 +0,0 @@
-#pragma once
-
-#include <filesystem>
-#include <functional>
-#include <memory>
-#include <opencv2/core/mat.hpp>
-#include <string>
-
-namespace pixelarium::imaging
-{
-using ImageQueryFunctor = std::function<void(const std::string&, void*, int*)>;
-
-/// @brief Enumeration of supported image file types.
-enum class ImageFileType
-{
-    /// @brief Represents an unknown or unsupported file type.
-    UNKNOWN = -10,
-    /// @brief Represents an abstract image type (e.g., a placeholder).
-    ABSTRACT = 0,
-    /// @brief Represents a PNG image file.
-    PNG = 1,
-    /// @brief Represents a JPG image file.
-    JPG = 2,
-    /// @brief Represents a CZI image file.
-    CZI = 3,
-};
-
-/// @brief An abstract interface to define a semantic query
-/// for a multi-dimensional image.
-struct IImageQuery
-{
-    virtual ~IImageQuery() = default;
-};
-
-/// @brief This aims to be a generic image abstraction
-/// meant for codec specific implementation.
-class IPixelariumImage
-{
-   public:
-    virtual ~IPixelariumImage() = default;
-
-    /// @brief Attempts to retrieve the image.
-    /// @return A unique pointer to a Mat object containing the image data,
-    /// or nullptr if the image is not found or cannot be retrieved.
-    /// May throw exceptions for multidimensional images.
-    virtual std::unique_ptr<cv::Mat> TryGetImage() = 0;
-
-    /// @brief Attempts to retrieve the image.
-    /// @return A unique pointer to a Mat object containing the image data,
-    /// or nullptr if the image is not found or cannot be retrieved.
-    virtual std::unique_ptr<cv::Mat> TryGetImage(const IImageQuery&) = 0;
-
-    /// @brief Attempts to retrieve a collection of images based on a query.
-    /// @param query The query object defining the images to retrieve.
-    /// @return A vector of unique pointers to cv::Mat objects. Each element is an image.
-    /// Returns an empty vector if no images are found or if an error occurs.
-    virtual std::vector<std::unique_ptr<cv::Mat>> TryGetImages(const IImageQuery&) = 0;
-
-    /// @brief Checks if the image is empty.
-    /// @return true if the image is empty, false otherwise.
-    virtual bool Empty() const noexcept = 0;
-
-    // default implemented
-   public:
-    /// @brief  Gets the resource identifier as a file path.
-    /// @return @c std::filesystem::path of the underlying resource.
-    virtual std::filesystem::path Uri() const noexcept { return this->uri_; }
-
-    /// @brief  Gets the resource name.
-    /// @note   Implementations of IPixelariumImage that live in memory
-    ///         should override this to get something meaningful as the name
-    ///         cannot be fetched from the resource uri in that case.
-    /// @return The name of the underlying resource.
-    virtual std::string Name() const noexcept
-    {
-        if (!this->uri_.empty())
-        {
-            return this->uri_.filename().string();
-        }
-
-        return {};
-    }
-
-   public:
-    const static ImageFileType type_{ImageFileType::ABSTRACT};
-
-   protected:
-    std::filesystem::path uri_;
-};
-}  // namespace pixelarium::imaging

lib/imaging/PixelariumImageFactory.cpp

@@ -1,36 +1,38 @@
 #include "PixelariumImageFactory.hpp"
 
-#include <algorithm>
 #include <cctype>
 #include <memory>
 
-#include "impl/PixelariumCzi.hpp"
-#include "impl/PixelariumJpg.hpp"
-#include "impl/PixelariumPng.hpp"
+#include "IPixelariumImage.hpp"
+#include "PixelariumCzi.hpp"
+#include "PixelariumJpg.hpp"
+#include "PixelariumMem.hpp"
+#include "PixelariumPng.hpp"
+#include "PixelariumTiff.hpp"
 
-
-/*static*/ std::unique_ptr<pixelarium::imaging::IPixelariumImage>
-pixelarium::imaging::PixelariumImageFactory::CreateImage(const std::string& uri)
+/*static*/ std::unique_ptr<pixelarium::imaging::IPixelariumImageCvMat>
+pixelarium::imaging::PixelariumImageFactory::CreateImage(const std::string& uri, const Log& log)
 {
     const auto res{std::filesystem::path(uri)};
     const auto target_type{ExtensionToType(res.extension().string())};
 
     switch (target_type)
     {
-        case ImageFileType::UNKNOWN:
+        case ImageFileType::kUnknown:
             return {};
-            break;
-        case ImageFileType::ABSTRACT:
+        case ImageFileType::kAbstract:
             return {};
-            break;
-        case ImageFileType::PNG:
+        case ImageFileType::kPng:
             return std::make_unique<PixelariumPng>(uri);
-            break;
-        case ImageFileType::JPG:
+        case ImageFileType::kJpg:
             return std::make_unique<PixelariumJpg>(uri);
-            break;
-        case ImageFileType::CZI:
-            return std::make_unique<PixelariumCzi>(uri);
-            break;
+        case ImageFileType::kCzi:
+            return std::make_unique<PixelariumCzi>(uri, log);
+        case ImageFileType::kTiff:
+            return std::make_unique<PixelariumTiff>(uri, log);
+        case ImageFileType::kMemory:
+            return std::make_unique<PixelariumMem>(cv::Mat(), uri, log);
+        default:
+            return {};
     }
 }

lib/imaging/PixelariumImageFactory.hpp

@@ -1,34 +0,0 @@
-#pragma once
-
-#include <memory>
-
-#include "IPixelariumImage.hpp"
-namespace pixelarium::imaging
-{
-constexpr pixelarium::imaging::ImageFileType ExtensionToType(const std::string& extension)
-{
-    std::string lower_ext{extension};
-    std::ranges::transform(extension, lower_ext.begin(), [](const char c) -> char { return std::tolower(c); });
-
-    if (lower_ext == ".jpg" || lower_ext == ".jpeg")
-    {
-        return pixelarium::imaging::ImageFileType::JPG;
-    }
-    if (lower_ext == ".png")
-    {
-        return pixelarium::imaging::ImageFileType::PNG;
-    }
-    if (lower_ext == ".czi")
-    {
-        return pixelarium::imaging::ImageFileType::CZI;
-    }
-
-    return pixelarium::imaging::ImageFileType::UNKNOWN;
-}
-
-class PixelariumImageFactory
-{
-   public:
-    static std::unique_ptr<IPixelariumImage> CreateImage(const std::string& uri);
-};
-}  // namespace pixelarium::imaging

lib/imaging/impl/PixelariumCzi.cpp

@@ -1,11 +1,125 @@
 #include "PixelariumCzi.hpp"
 
+#include <cstdint>
 #include <filesystem>
+#include <format>
+#include <memory>
+#include <opencv2/imgcodecs.hpp>
+#include <optional>
 #include <stdexcept>
 
+#include "ILog.hpp"
 #include "libCZI.h"
+#include "libCZI_Pixels.h"
 
-pixelarium::imaging::PixelariumCzi::PixelariumCzi(const std::string& uri)
+namespace
+{
+bool comp_blockinfo_params(const pixelarium::imaging::CziParams& params, const libCZI::SubBlockInfo& info)
+{
+    bool res{true};
+
+    info.coordinate.EnumValidDimensions(
+        [&](libCZI::DimensionIndex dim, int start) -> bool
+        {
+            if (params.dimension_map.at(dim) == start)
+            {
+                return true;
+            }
+
+            res &= false;
+            return true;
+        });
+
+    return res;
+}
+
+constexpr int try_get_index_match(const pixelarium::imaging::CziParams& params, libCZI::ICZIReader& reader)
+{
+    int index{-1};
+    reader.EnumerateSubBlocks(
+        [&](int idx, const libCZI::SubBlockInfo& info) -> bool
+        {
+            if (comp_blockinfo_params(params, info))
+            {
+                index = idx;
+                // returning false will stop the enumeration
+                return false;
+            }
+
+            return true;
+        });
+
+    return index;
+}
+
+}  // namespace
+
+std::optional<cv::Mat> CZISubBlockToCvMat(std::shared_ptr<libCZI::IBitmapData> bitmap, libCZI::PixelType pixeltype,
+                                          const pixelarium::utils::log::ILog& log)
+{
+    const auto cv_pixel = GetCVPixelTypeAndSize(pixeltype);
+
+    // ToDo(MAK): fix this makeshift pixel-type-catch
+    if (cv_pixel.size < 0 || cv_pixel.size > 4) return std::nullopt;
+
+    log.Info(std::format("{}: source pixel type {}, target cv pixel type {}, pixel size {}", __PRETTY_FUNCTION__,
+                         static_cast<uint8_t>(pixeltype), cv_pixel.type, cv_pixel.size));
+
+    size_t height{bitmap->GetHeight()};
+    size_t width{bitmap->GetWidth()};
+    auto fill_mat = cv::Mat(height, width, cv_pixel.type);
+
+    if (const auto bitmap_info = bitmap->Lock(); bitmap_info.ptrDataRoi)
+    {
+        for (size_t h{0}; h < height; ++h)
+        {
+            unsigned char* source_row = ((unsigned char*)bitmap_info.ptrDataRoi) + bitmap_info.stride * h;
+            unsigned char* target_row = fill_mat.ptr(h);
+
+            for (size_t w{0}; w < width; ++w)
+            {
+                switch (cv_pixel.size)
+                {
+                    case 1:
+                        target_row[w] = source_row[w];
+                        break;
+                    case 2:
+                        reinterpret_cast<unsigned short*>(target_row)[w] =
+                            reinterpret_cast<unsigned short*>(source_row)[w];
+                        break;
+                    case 3:
+                        target_row[3 * w] = source_row[3 * w];
+                        target_row[3 * w + 1] = source_row[3 * w + 1];
+                        target_row[3 * w + 2] = source_row[3 * w + 2];
+                        break;
+                    case 4:
+                        reinterpret_cast<std::int32_t*>(target_row)[w] = reinterpret_cast<std::int32_t*>(source_row)[w];
+                        break;
+                    default:
+                        throw std::runtime_error("Unknown pixel type requested!");
+                        break;
+                }
+            }
+        }
+    }
+
+    // this is outside of the previous if-clause on purpose:
+    // no matter if we reach the inner scope of this clause, we locked the bitmap,
+    // so here it has to be unlocked.
+    bitmap->Unlock();
+
+    return fill_mat;
+}
+
+std::optional<cv::Mat> pixelarium::imaging::PixelariumCzi::SubblockToCvMat(int index)
+{
+    log_.Info(std::format("{}: constructing bitmap with index {}", __PRETTY_FUNCTION__, index));
+    auto block = this->czi_reader_->ReadSubBlock(index);
+    auto bitmap = block->CreateBitmap();
+    return CZISubBlockToCvMat(bitmap, block->GetSubBlockInfo().pixelType, log_);
+}
+
+pixelarium::imaging::PixelariumCzi::PixelariumCzi(const std::string& uri, const Log& log) : log_(log)
 {
     if (!std::filesystem::exists(uri))
     {
@@ -19,89 +133,26 @@ pixelarium::imaging::PixelariumCzi::PixelariumCzi(const std::string& uri)
     this->czi_reader_ = libCZI::CreateCZIReader();
     this->czi_reader_->Open(stream);
     this->image_statistics_ = this->czi_reader_->GetStatistics();
-}
 
-std::unique_ptr<cv::Mat> CZISubBlockToCvMat(std::shared_ptr<libCZI::IBitmapData> bitmap, libCZI::PixelType pixeltype)
-{
-    size_t pixel_size{0};
-    int target_type;
-
-    switch (pixeltype)
-    {
-        case libCZI::PixelType::Gray8:
-            pixel_size = 1;
-            target_type = CV_8U;
-            break;
-        case libCZI::PixelType::Gray16:
-            pixel_size = 2;
-            target_type = CV_16U;
-            break;
-        case libCZI::PixelType::Bgr24:
-            pixel_size = 3;
-            target_type = CV_8UC3;
-            break;
-        case libCZI::PixelType::Bgra32:
-            target_type = CV_8UC4;
-        case libCZI::PixelType::Gray32:
-            target_type = CV_32S;
-        case libCZI::PixelType::Gray32Float:
-            target_type = CV_32F;
-            pixel_size = 4;
-            break;
-        // case libCZI::PixelType::Gray64ComplexFloat:
-        // case libCZI::PixelType::Gray64Float:
-        //    target_type =
-        //    pixel_size = 8;
-        //    break;
-        default:
-            pixel_size = -1;
-            break;
-    }
-
-    if (pixel_size < 0) return nullptr;
-
-    size_t height{bitmap->GetHeight()};
-    size_t width{bitmap->GetWidth()};
-    auto fill_mat = std::make_unique<cv::Mat>(height, width, target_type);
-
-    auto bitmap_info = bitmap->Lock();
-
-    for (size_t h{0}; h < height; ++h)
-    {
-        unsigned char* source_row = ((unsigned char*)bitmap_info.ptrDataRoi) + bitmap_info.stride * h;
-        unsigned char* target_row = fill_mat->ptr(h);
-
-        for (size_t w{0}; w < width; ++w)
+    this->image_statistics_.dimBounds.EnumValidDimensions(
+        [&](libCZI::DimensionIndex dim, int start, int) -> bool
         {
-            switch (pixel_size)
-            {
-                case 1:
-                    target_row[w] = source_row[w];
-                    break;
-                case 2:
-                    reinterpret_cast<unsigned short*>(target_row)[w] = reinterpret_cast<unsigned short*>(source_row)[w];
-                    break;
-                case 3:
-                    target_row[3 * w] = source_row[3 * w];
-                    target_row[3 * w + 1] = source_row[3 * w + 1];
-                    target_row[3 * w + 2] = source_row[3 * w + 2];
-                    break;
-                default:
-                    throw std::runtime_error("Unknown pixel type requested!");
-                    break;
-            }
-        }
+            this->dimension_map_[dim] = start;
+            return true;
+        });
+}
+
+std::optional<cv::Mat> pixelarium::imaging::PixelariumCzi::TryGetImage() { return SubblockToCvMat(0); }
+
+std::optional<cv::Mat> pixelarium::imaging::PixelariumCzi::TryGetImage(const IImageQuery& query)
+{
+    const auto czi_query = static_cast<const CziParams&>(query);
+    int index = try_get_index_match(czi_query, *this->czi_reader_);
+
+    if (index < 0)
+    {
+        return SubblockToCvMat(0);
     }
 
-    bitmap->Unlock();
-    return fill_mat;
-}
-
-std::unique_ptr<cv::Mat> pixelarium::imaging::PixelariumCzi::TryGetImage()
-{
-    auto block = this->czi_reader_->ReadSubBlock(0);
-    auto bitmap = block->CreateBitmap();
-    auto res = CZISubBlockToCvMat(bitmap, block->GetSubBlockInfo().pixelType);
-
-    return res;
+    return SubblockToCvMat(index);
 }

lib/imaging/impl/PixelariumCzi.hpp

@@ -1,58 +0,0 @@
-#pragma once
-
-#include <memory>
-#include <string>
-
-#include "../IPixelariumImage.hpp"
-#include "libCZI.h"
-
-namespace pixelarium::imaging
-{
-struct CziParams : public IImageQuery
-{
-    
-};
-
-class PixelariumCzi : public IPixelariumImage
-{
-   public:
-    explicit PixelariumCzi(const std::string& uri);
-    ~PixelariumCzi()
-    {
-        if (this->czi_reader_)
-            this->czi_reader_->Close();
-    }
-
-    // IPixelariumImage member implementations
-   public:
-    std::unique_ptr<cv::Mat> TryGetImage() override;
-
-    std::unique_ptr<cv::Mat> TryGetImage(const IImageQuery&) override
-    {
-        // ToDo: proper error
-        throw std::runtime_error("Not implemented.");
-    }
-
-    std::vector<std::unique_ptr<cv::Mat>> TryGetImages(const IImageQuery&) override
-    {
-        // ToDo: proper error
-        throw std::runtime_error("Not implemented.");
-    }
-
-    bool Empty() const noexcept override { return this->is_empty_; }
-
-    const libCZI::SubBlockStatistics& GetStatistics() const { return this->image_statistics_; }
-
-   public:
-    const static ImageFileType type_{ImageFileType::CZI};
-
-   private:
-    // this should be set by each image getter
-    // after a new cv::Mat could be instantiated
-    bool is_empty_{true};
-
-    libCZI::SubBlockStatistics image_statistics_;
-
-    std::shared_ptr<libCZI::ICZIReader> czi_reader_;
-};
-}  // namespace pixelarium::imaging

lib/imaging/impl/PixelariumJpg.cpp

@@ -1,7 +1,5 @@
 #include "PixelariumJpg.hpp"
 
-#include <filesystem>
-#include <memory>
 #include <opencv2/imgcodecs.hpp>
 #include <string>
 
@@ -16,11 +14,11 @@ pixelarium::imaging::PixelariumJpg::PixelariumJpg(const std::string& uri)
     this->uri_ = std::filesystem::path(uri);
 }
 
-std::unique_ptr<cv::Mat> pixelarium::imaging::PixelariumJpg::TryGetImage()
+std::optional<cv::Mat> pixelarium::imaging::PixelariumJpg::TryGetImage()
 {
     try
     {
-        auto img = std::make_unique<cv::Mat>(cv::imread(this->uri_.string()));
+        auto img = cv::Mat(cv::imread(this->uri_.string()));
 
         this->is_empty_ = false;
 

lib/imaging/impl/PixelariumMem.cpp

@@ -0,0 +1,26 @@
+#include "PixelariumMem.hpp"
+
+#include <filesystem>
+#include <memory>
+#include <opencv2/imgcodecs.hpp>
+#include <string>
+
+pixelarium::imaging::PixelariumMem::PixelariumMem(const cv::Mat& img, const std::string& name, const Log& log)
+    : img_(img), log_(log), name_(name)
+{
+    this->is_empty_ = false;
+    this->uri_ = std::filesystem::path();
+}
+
+std::optional<cv::Mat> pixelarium::imaging::PixelariumMem::TryGetImage()
+{
+    // ToDo: this craving for a revision of the whole concept:
+    // the interface requires a unique_ptr here. This concept was designed to "create an in-memory image on demand" sort
+    // of.
+    // I.e., it only makes sense for the file types that do not already manage a cv::Mat in memory.
+    // PixelariumMem is meant for exactly this in-memory management of a cv::Mat though.
+    // So, returning a unique_ptr from it in the following semantic essentially calls the
+    // copy constructor of cv::Mat. This is potentially not "super bad", but at least it requires attention at some
+    // point.
+    return this->img_;
+}

lib/imaging/impl/PixelariumPng.cpp

@@ -16,11 +16,11 @@ pixelarium::imaging::PixelariumPng::PixelariumPng(const std::string& uri)
     this->uri_ = std::filesystem::path(uri);
 }
 
-std::unique_ptr<cv::Mat> pixelarium::imaging::PixelariumPng::TryGetImage()
+std::optional<cv::Mat> pixelarium::imaging::PixelariumPng::TryGetImage()
 {
     try
     {
-        auto img = std::make_unique<cv::Mat>(cv::imread(this->uri_.string()));
+        auto img = cv::Mat(cv::imread(this->uri_.string()));
 
         this->is_empty_ = false;
 

lib/imaging/impl/PixelariumTiff.cpp

@@ -0,0 +1,34 @@
+#include "PixelariumTiff.hpp"
+
+#include <filesystem>
+#include <memory>
+#include <opencv2/imgcodecs.hpp>
+#include <string>
+
+pixelarium::imaging::PixelariumTiff::PixelariumTiff(const std::string& uri, const Log& log) : log_(log)
+{
+    if (!std::filesystem::exists(uri))
+    {
+        throw std::runtime_error("Render file not found.");
+    }
+
+    this->is_empty_ = false;
+    this->uri_ = std::filesystem::path(uri);
+}
+
+std::optional<cv::Mat> pixelarium::imaging::PixelariumTiff::TryGetImage()
+{
+    try
+    {
+        auto img = cv::Mat(cv::imread(this->uri_.string()));
+
+        this->is_empty_ = false;
+
+        return img;
+    }
+    catch (const std::exception& e)
+    {
+        this->is_empty_ = true;
+        return {};
+    }
+}

lib/imaging/impl/include/PixelariumCzi.hpp

@@ -0,0 +1,100 @@
+#pragma once
+
+#include <memory>
+#include <string>
+
+#include "ILog.hpp"
+#include "IPixelariumImage.hpp"
+#include "libCZI.h"
+#include "libCZI_Pixels.h"
+
+namespace
+{
+struct CvPixelTypeAndSize
+{
+    int size{-1};
+    int type{-1};
+};
+
+template <typename P>
+[[nodiscard]] constexpr auto GetCVPixelTypeAndSize(P p) noexcept -> CvPixelTypeAndSize
+{
+    switch (p)
+    {
+        case libCZI::PixelType::Gray8:
+            return {1, CV_8U};
+        case libCZI::PixelType::Gray16:
+            return {2, CV_16U};
+        case libCZI::PixelType::Bgr24:
+            return {3, CV_8UC3};
+        case libCZI::PixelType::Bgra32:
+            return {4, CV_8UC4};
+        case libCZI::PixelType::Gray32:
+            return {4, CV_32S};
+        case libCZI::PixelType::Gray32Float:
+            return {4, CV_32F};
+        default:
+            return {};
+    }
+}
+}  // namespace
+
+namespace pixelarium::imaging
+{
+/// @brief An implementation of IImageQuery to work on CZI images.
+/// @note  Check the documentation here https://zeiss.github.io/libczi/pages/mainpage.html#czi-in-a-nutshell
+struct CziParams : public IImageQuery
+{
+    /// @brief A map providing the start coordinate for each dimension in the CZI
+    std::unordered_map<libCZI::DimensionIndex, int> dimension_map;
+};
+
+/// @brief Implements support for .czi-images in the realm of IPixelariumImage
+class PixelariumCzi : public IPixelariumImageCvMat
+{
+    using Log = pixelarium::utils::log::ILog;
+
+   public:
+    explicit PixelariumCzi(const std::string& uri, const Log& log);
+    ~PixelariumCzi()
+    {
+        if (this->czi_reader_) this->czi_reader_->Close();
+    }
+
+    // IPixelariumImage member implementations
+   public:
+    std::optional<cv::Mat> TryGetImage() override;
+
+    std::optional<cv::Mat> TryGetImage(const IImageQuery&) override;
+
+    std::vector<std::optional<cv::Mat>> TryGetImages(const IImageQuery&) override
+    {
+        // ToDo: proper error
+        throw std::runtime_error("Not implemented.");
+    }
+
+   public:
+    bool Empty() const noexcept override { return this->is_empty_; }
+
+    const libCZI::SubBlockStatistics& GetStatistics() const { return this->image_statistics_; }
+
+   public:
+    const static ImageFileType type_{ImageFileType::kCzi};
+
+   private:
+    std::optional<cv::Mat> SubblockToCvMat(int index);
+
+   private:
+    // this should be set by each image getter
+    // after a new cv::Mat could be instantiated
+    bool is_empty_{true};
+
+    libCZI::SubBlockStatistics image_statistics_;
+
+    std::shared_ptr<libCZI::ICZIReader> czi_reader_;
+
+    std::unordered_map<libCZI::DimensionIndex, int> dimension_map_;
+
+    const Log& log_;
+};
+}  // namespace pixelarium::imaging

lib/imaging/impl/include/PixelariumJpg.hpp

@@ -3,35 +3,37 @@
 #include <stdexcept>
 #include <string>
 
-#include "../IPixelariumImage.hpp"
+#include "IPixelariumImage.hpp"
 
 namespace pixelarium::imaging
 {
-class PixelariumJpg : public IPixelariumImage
+/// @brief Implements support for .jpg-images in the realm of IPixelariumImage
+class PixelariumJpg : public IPixelariumImageCvMat
 {
    public:
     explicit PixelariumJpg(const std::string& url);
 
     // IPixelariumImage member implementations
    public:
-    std::unique_ptr<cv::Mat> TryGetImage() override;
+    std::optional<cv::Mat> TryGetImage() override;
 
-    std::unique_ptr<cv::Mat> TryGetImage(const IImageQuery&) override
+    std::optional<cv::Mat> TryGetImage(const IImageQuery&) override
     {
         // ToDo: proper error
         throw std::runtime_error("Not possible with jpg.");
     }
 
-    std::vector<std::unique_ptr<cv::Mat>> TryGetImages(const IImageQuery&) override
+    std::vector<std::optional<cv::Mat>> TryGetImages(const IImageQuery&) override
     {
         // ToDo: proper error
         throw std::runtime_error("Not possible with jpg.");
     }
 
+   public:
     bool Empty() const noexcept override { return this->is_empty_; }
 
    public:
-    const static ImageFileType type_{ImageFileType::JPG};
+    const static ImageFileType type_{ImageFileType::kJpg};
 
    private:
     // this should be set by each image getter

lib/imaging/impl/include/PixelariumMem.hpp

@@ -0,0 +1,47 @@
+#pragma once
+
+#include <stdexcept>
+#include <string>
+
+#include "ILog.hpp"
+#include "IPixelariumImage.hpp"
+
+namespace pixelarium::imaging
+{
+/// @brief Implements support for in-memory images in the realm of IPixelariumImage
+class PixelariumMem : public IPixelariumImageCvMat
+{
+    using Log = pixelarium::utils::log::ILog;
+
+   public:
+    explicit PixelariumMem(const cv::Mat& img, const std::string& name, const Log& log);
+
+    // IPixelariumImage member implementations
+   public:
+    std::optional<cv::Mat> TryGetImage() override;
+
+    std::optional<cv::Mat> TryGetImage(const IImageQuery&) override { throw std::runtime_error("Not implemented."); }
+
+    std::vector<std::optional<cv::Mat>> TryGetImages(const IImageQuery&) override
+    {
+        throw std::runtime_error("Not implemented.");
+    }
+
+    void SetImage(const cv::Mat& img) { this->img_ = img; }
+
+    std::string Name() const noexcept override { return this->name_; }
+
+    bool Empty() const noexcept override { return this->is_empty_; }
+
+   public:
+    const static ImageFileType type_{ImageFileType::kMemory};
+
+   private:
+    // this should be set by each image getter
+    // after a new cv::Mat could be instantiated
+    bool is_empty_{true};
+    cv::Mat img_;
+    const Log& log_;
+    std::string name_;
+};
+}  // namespace pixelarium::imaging

lib/imaging/impl/include/PixelariumPng.hpp

@@ -3,26 +3,27 @@
 #include <stdexcept>
 #include <string>
 
-#include "../IPixelariumImage.hpp"
+#include "IPixelariumImage.hpp"
 
 namespace pixelarium::imaging
 {
-class PixelariumPng : public IPixelariumImage
+/// @brief Implements support for .png-images in the realm of IPixelariumImage
+class PixelariumPng : public IPixelariumImageCvMat
 {
    public:
     explicit PixelariumPng(const std::string& url);
 
     // IPixelariumImage member implementations
    public:
-    std::unique_ptr<cv::Mat> TryGetImage() override;
+    std::optional<cv::Mat> TryGetImage() override;
 
-    std::unique_ptr<cv::Mat> TryGetImage(const IImageQuery&) override
+    std::optional<cv::Mat> TryGetImage(const IImageQuery&) override
     {
         // ToDo: proper error
         throw std::runtime_error("Not possible with png.");
     }
 
-    std::vector<std::unique_ptr<cv::Mat>> TryGetImages(const IImageQuery&) override
+    std::vector<std::optional<cv::Mat>> TryGetImages(const IImageQuery&) override
     {
         // ToDo: proper error
         throw std::runtime_error("Not possible with png.");
@@ -31,7 +32,7 @@ class PixelariumPng : public IPixelariumImage
     bool Empty() const noexcept override { return this->is_empty_; }
 
    public:
-    const static ImageFileType type_{ImageFileType::PNG};
+    const static ImageFileType type_{ImageFileType::kPng};
 
    private:
     // this should be set by each image getter

lib/imaging/impl/include/PixelariumTiff.hpp

@@ -0,0 +1,46 @@
+#pragma once
+
+#include <stdexcept>
+#include <string>
+
+#include "ILog.hpp"
+#include "IPixelariumImage.hpp"
+
+namespace pixelarium::imaging
+{
+/// @brief Implements support for .tiff-images in the realm of IPixelariumImage
+class PixelariumTiff : public IPixelariumImageCvMat
+{
+    using Log = pixelarium::utils::log::ILog;
+
+   public:
+    explicit PixelariumTiff(const std::string& uri, const Log& log);
+
+    // IPixelariumImage member implementations
+   public:
+    std::optional<cv::Mat> TryGetImage() override;
+
+    std::optional<cv::Mat> TryGetImage(const IImageQuery&) override
+    {
+        // ToDo: proper error
+        throw std::runtime_error("Not possible with tiff.");
+    }
+
+    std::vector<std::optional<cv::Mat>> TryGetImages(const IImageQuery&) override
+    {
+        // ToDo: proper error
+        throw std::runtime_error("Not possible with tiff.");
+    }
+
+    bool Empty() const noexcept override { return this->is_empty_; }
+
+   public:
+    const static ImageFileType type_{ImageFileType::kTiff};
+
+   private:
+    // this should be set by each image getter
+    // after a new cv::Mat could be instantiated
+    bool is_empty_{true};
+    const Log& log_;
+};
+}  // namespace pixelarium::imaging

lib/imaging/include/IPixelariumImage.hpp

@@ -0,0 +1,153 @@
+#pragma once
+
+#include <filesystem>
+#include <functional>
+#include <opencv2/core/mat.hpp>
+#include <string>
+
+namespace pixelarium::imaging
+{
+using ImageQueryFunctor = std::function<void(const std::string&, void*, int*)>;
+
+/// @brief Enumeration of supported image file types.
+enum class ImageFileType
+{
+    /// @brief Represents an unknown or unsupported file type.
+    kUnknown = -10,
+    /// @brief Represents an abstract image type (e.g., a placeholder).
+    kAbstract = 0,
+    /// @brief Represents a PNG image file.
+    kPng = 1,
+    /// @brief Represents a JPG image file.
+    kJpg = 2,
+    /// @brief Represents a CZI image file.
+    kCzi = 3,
+    /// @brief Represents a TIFF image file.
+    kTiff = 4,
+    /// @brief Represents an in-memory image.
+    kMemory = 5,
+};
+
+/// @brief An abstract interface to define a semantic query
+/// for a multi-dimensional image.
+struct IImageQuery
+{
+    virtual ~IImageQuery() = default;
+};
+
+/// @brief This aims to be a generic image abstraction
+/// meant for codec specific implementation.
+template <class Data>
+class IPixelariumImage
+{
+   public:
+    virtual ~IPixelariumImage() = default;
+
+    /// @brief Attempts to retrieve the image.
+    /// @return A unique pointer to a Mat object containing the image data,
+    /// or nullptr if the image is not found or cannot be retrieved.
+    /// May throw exceptions for multidimensional images.
+    virtual std::optional<Data> TryGetImage() = 0;
+
+    /// @brief Attempts to retrieve the image.
+    /// @param query The query object defining the images to retrieve.
+    /// @return A unique pointer to a Mat object containing the image data,
+    /// or nullptr if the image is not found or cannot be retrieved.
+    virtual std::optional<Data> TryGetImage(const IImageQuery& query) = 0;
+
+    /// @brief Attempts to retrieve a collection of images based on a query.
+    /// @param query The query object defining the images to retrieve.
+    /// @return A vector of unique pointers to cv::Mat objects. Each element is an image.
+    /// Returns an empty vector if no images are found or if an error occurs.
+    virtual std::vector<std::optional<Data>> TryGetImages(const IImageQuery& query) = 0;
+
+    /// @brief Checks if the image is empty.
+    /// @return true if the image is empty, false otherwise.
+    virtual bool Empty() const noexcept = 0;
+
+    // default implemented
+   public:
+    /// @brief  Gets the resource identifier as a file path.
+    /// @return @c std::filesystem::path of the underlying resource.
+    virtual std::filesystem::path Uri() const noexcept { return this->uri_; }
+
+    /// @brief  Gets the resource name.
+    /// @note   Implementations of IPixelariumImage that live in memory
+    ///         should override this to get something meaningful as the name
+    ///         cannot be fetched from the resource uri in that case.
+    /// @return The name of the underlying resource.
+    virtual std::string Name() const noexcept
+    {
+        if (!this->uri_.empty())
+        {
+            return this->uri_.filename().string();
+        }
+
+        return {};
+    }
+
+   public:
+    const static ImageFileType type_{ImageFileType::kAbstract};
+
+   protected:
+    std::filesystem::path uri_;
+};
+
+/// @brief Interface template specialization of IPixelariumImage
+///        using cv::Mat as the wrapped data type.
+class IPixelariumImageCvMat : public IPixelariumImage<cv::Mat>
+{
+   public:
+    virtual ~IPixelariumImageCvMat() = default;
+
+    /// @brief Attempts to retrieve the image.
+    /// @return A unique pointer to a Mat object containing the image data,
+    /// or nullptr if the image is not found or cannot be retrieved.
+    /// May throw exceptions for multidimensional images.
+    virtual std::optional<cv::Mat> TryGetImage() = 0;
+
+    /// @brief Attempts to retrieve the image.
+    /// @param query The query object defining the images to retrieve.
+    /// @return A unique pointer to a Mat object containing the image data,
+    /// or nullptr if the image is not found or cannot be retrieved.
+    virtual std::optional<cv::Mat> TryGetImage(const IImageQuery& query) = 0;
+
+    /// @brief Attempts to retrieve a collection of images based on a query.
+    /// @param query The query object defining the images to retrieve.
+    /// @return A vector of unique pointers to cv::Mat objects. Each element is an image.
+    /// Returns an empty vector if no images are found or if an error occurs.
+    virtual std::vector<std::optional<cv::Mat>> TryGetImages(const IImageQuery& query) = 0;
+
+    /// @brief Checks if the image is empty.
+    /// @return true if the image is empty, false otherwise.
+    virtual bool Empty() const noexcept = 0;
+
+    /// @brief Saves an image to the resource identifier given by uri.
+    /// @return true if saving was successful, false otherwise.
+    virtual bool SaveImage(const std::string& uri);
+
+    // default implemented
+   public:
+    /// @brief  Gets the resource identifier as a file path.
+    /// @return @c std::filesystem::path of the underlying resource.
+    virtual std::filesystem::path Uri() const noexcept { return this->uri_; }
+
+    /// @brief  Gets the resource name.
+    /// @note   Implementations of IPixelariumImage that live in memory
+    ///         should override this to get something meaningful as the name
+    ///         cannot be fetched from the resource uri in that case.
+    /// @return The name of the underlying resource.
+    virtual std::string Name() const noexcept
+    {
+        if (!this->uri_.empty())
+        {
+            return this->uri_.filename().string();
+        }
+
+        return {};
+    }
+
+   public:
+    const static ImageFileType type_{ImageFileType::kAbstract};
+};
+}  // namespace pixelarium::imaging

lib/imaging/include/PixelariumImageFactory.hpp

@@ -0,0 +1,43 @@
+#pragma once
+
+#include <memory>
+
+#include "ILog.hpp"
+#include "IPixelariumImage.hpp"
+
+namespace pixelarium::imaging
+{
+constexpr pixelarium::imaging::ImageFileType ExtensionToType(const std::string& extension)
+{
+    std::string lower_ext{extension};
+    std::ranges::transform(extension, lower_ext.begin(), [](const char c) -> char { return std::tolower(c); });
+
+    if (lower_ext == ".jpg" || lower_ext == ".jpeg")
+    {
+        return pixelarium::imaging::ImageFileType::kJpg;
+    }
+    if (lower_ext == ".png")
+    {
+        return pixelarium::imaging::ImageFileType::kPng;
+    }
+    if (lower_ext == ".czi")
+    {
+        return pixelarium::imaging::ImageFileType::kCzi;
+    }
+    if (lower_ext == ".tiff" || lower_ext == ".tif")
+    {
+        return pixelarium::imaging::ImageFileType::kTiff;
+    }
+
+    return pixelarium::imaging::ImageFileType::kUnknown;
+}
+
+/// @brief Factory for instantiating implementations of IPixelariumImage based on the given file type.
+class PixelariumImageFactory
+{
+    using Log = utils::log::ILog;
+
+   public:
+    static std::unique_ptr<IPixelariumImageCvMat> CreateImage(const std::string& uri, const Log& log);
+};
+}  // namespace pixelarium::imaging

lib/rendering/CMakeLists.txt

@@ -1,26 +0,0 @@
-set(RENDERLIBNAME pixelariumrenderlib)
-
-set(RENDERLIBSRC
-  RenderHelpers.hpp
-  RenderHelpers.cpp
-  CvMatRender.hpp
-  CvMatRender.cpp
-  RenderImageManager.hpp
-  RenderImageManager.cpp
-  IPixelariumImageView.hpp
-  PixelariumImageViewDefault.hpp
-  PixelariumImageViewDefault.cpp
-  PixelariumImageViewCzi.hpp
-  PixelariumImageViewCzi.cpp
-  ImageViewFactory.hpp
-  ImageViewFactory.cpp)
-
-add_library(${RENDERLIBNAME} STATIC
-  ${RENDERLIBSRC})
-
-target_link_libraries(${RENDERLIBNAME}
-  PRIVATE pixelariumimagelib)
-
-target_include_directories(${RENDERLIBNAME}
-  PRIVATE ${CMAKE_SOURCE_DIR}/lib
-  PRIVATE ${imgui_DIR})

lib/rendering/IPixelariumImageView.hpp

@@ -1,28 +0,0 @@
-#pragma once
-
-#include <memory>
-
-#include "imaging/IPixelariumImage.hpp"
-#include "rendering/CvMatRender.hpp"
-
-namespace pixelarium::render
-{
-class IPixelariumImageView
-{
-   public:
-    virtual ~IPixelariumImageView() = default;
-    virtual void ShowImage() = 0;
-
-    // default implemented
-   public:
-    virtual const bool* GetStatus() const noexcept { return &this->open_p; }
-    virtual void ForceUpdate() noexcept { this->is_dirty_ = true; }
-
-   protected:
-    std::shared_ptr<imaging::IPixelariumImage> img_{};
-    std::unique_ptr<cv::Mat> cached_image_{};
-    render::CvMatRender render_;
-    bool open_p{true};
-    bool is_dirty_{true};
-};
-}  // namespace pixelarium::render

lib/rendering/ImageViewFactory.cpp

@@ -1,49 +0,0 @@
-#include "ImageViewFactory.hpp"
-
-#include <memory>
-#include "imaging/PixelariumImageFactory.hpp"
-#include "rendering/IPixelariumImageView.hpp"
-#include "rendering/PixelariumImageViewCzi.hpp"
-#include "rendering/PixelariumImageViewDefault.hpp"
-
-/// @brief Creates a PixelariumImageView from a resource image.
-/// @param image_id The ID of the image resource to render.
-/// @return A unique pointer to the PixelariumImageView, or nullptr if the image resource is not found or is empty.  The image data is copied.
-std::unique_ptr<pixelarium::render::IPixelariumImageView> pixelarium::render::ImageViewFactory::RenderImage(
-    size_t image_id)
-{
-    auto res{this->image_pool_.GetResource(image_id)};
-
-    auto img{res.lock()};
-
-    if (img == nullptr)
-    {
-        return {};
-    }
-
-    if (img->Empty())
-    {
-        return {};
-    }
-
-    auto type = imaging::ExtensionToType(img->Uri().extension().string());
-
-    switch (type)
-    {
-        case imaging::ImageFileType::UNKNOWN:
-        case imaging::ImageFileType::ABSTRACT:
-            return {};
-        case imaging::ImageFileType::PNG:
-        case imaging::ImageFileType::JPG:
-            log_.Info("Creating a Default View");
-            // beware: here we copy the actual image resource over to the new image
-            return std::make_unique<PixelariumImageViewDefault>(img);
-        case imaging::ImageFileType::CZI:
-            log_.Info("{}: Creating a CZI View");
-            // beware: here we copy the actual image resource over to the new image
-            return std::make_unique<PixelariumImageViewCzi>(img);
-        default:
-            return {};
-    }
-}
-

lib/rendering/ImageViewFactory.hpp

@@ -1,24 +0,0 @@
-#pragma once
-
-#include "PixelariumImageViewDefault.hpp"
-#include "rendering/IPixelariumImageView.hpp"
-#include "resources/resource.hpp"
-#include "utilities/ILog.hpp"
-namespace pixelarium::render
-{
-class ImageViewFactory
-{
-    using Image = imaging::IPixelariumImage;
-    using Pool = resources::ImageResourcePool;
-    using Log = utils::log::ILog;
-
-   public:
-    explicit ImageViewFactory(Pool& pool, const Log& log) : image_pool_(pool), log_(log) {}
-
-    std::unique_ptr<IPixelariumImageView> RenderImage(size_t id);
-
-   private:
-    Pool& image_pool_;
-    const Log& log_;
-};
-}  // namespace pixelarium::render

lib/rendering/PixelariumImageViewCzi.cpp

@@ -1,66 +0,0 @@
-#include "PixelariumImageViewCzi.hpp"
-
-#include <format>
-
-#include "RenderHelpers.hpp"
-#include "imaging/IPixelariumImage.hpp"
-#include "imaging/impl/PixelariumCzi.hpp"
-#include "imgui.h"
-
-/// @brief Displays the image in an ImGui window.
-///
-/// If the image is null, empty, or has an empty name, the function returns immediately.  Otherwise, it creates an ImGui
-/// window with a horizontal scrollbar and menu bar. The image is rendered using the CvMatRender object, resizing it to
-/// fit the available window space.  The raw and rendered dimensions are displayed below the image.
-void pixelarium::render::PixelariumImageViewCzi::ShowImage()
-{
-    auto czi_img = std::static_pointer_cast<imaging::PixelariumCzi>(this->img_);
-
-    if (!czi_img) return;
-
-    if (!this->cached_image_ || this->is_dirty_)
-    {
-        this->cached_image_ = this->img_->TryGetImage();
-        this->is_dirty_ = false;
-    }
-
-    if (czi_img->Empty() || this->img_->type_ == imaging::ImageFileType::UNKNOWN || !cached_image_ ||
-        czi_img->Name().empty())
-    {
-        // do nothing
-        return;
-    }
-
-    ImGui::Begin(this->img_->Name().c_str(), &this->open_p,
-                 ImGuiWindowFlags_HorizontalScrollbar | ImGuiWindowFlags_MenuBar);
-
-    this->curr_dim_ = ImGui::GetContentRegionAvail();
-    auto new_dim = ImGui::GetContentRegionAvail();
-    auto texture =
-        dim_changed_p(this->curr_dim_, new_dim)
-            ? this->render_.Render(static_cast<size_t>(this->curr_dim_.x), static_cast<size_t>(this->curr_dim_.y))
-            : this->render_.Render();
-
-    this->curr_dim_ = new_dim;
-
-    ImVec2 dim(cached_image_->cols, cached_image_->rows);
-
-    ImGui::Image(reinterpret_cast<ImTextureID>(reinterpret_cast<void*>(texture)),
-                 aspect_const_dimensions(dim, new_dim));
-
-    ImGui::Separator();
-    ImGui::Text("%s", std::format("   Raw Dimensions W : {}, H: {}", dim.x, dim.y).c_str());
-    ImGui::Text("%s", std::format("Render Dimensions W : {}, H: {}", curr_dim_.x, curr_dim_.y).c_str());
-    ImGui::Text("Dimensions");
-    ImGui::Separator();
-
-    auto stats = czi_img->GetStatistics();
-    stats.dimBounds.EnumValidDimensions(
-        [&](libCZI::DimensionIndex dim, int start, int size) -> bool
-        {
-            ImGui::Text("%c\t Start: %d\t End: %d", libCZI::Utils::DimensionToChar(dim), start, size);
-            return true;
-        });
-
-    ImGui::End();
-}

lib/rendering/PixelariumImageViewCzi.hpp

@@ -1,31 +0,0 @@
-#pragma once
-
-#include "imgui.h"
-#include "rendering/IPixelariumImageView.hpp"
-
-namespace pixelarium::render
-{
-class PixelariumImageViewCzi : public IPixelariumImageView
-{
-    using Image = imaging::IPixelariumImage;
-    using Render = render::CvMatRender;
-
-   public:
-    explicit PixelariumImageViewCzi(std::shared_ptr<Image> img)
-    {
-        img_ = img;
-        render_ = Render(img_);
-    }
-    PixelariumImageViewCzi() = delete;
-    PixelariumImageViewCzi(PixelariumImageViewCzi&) = delete;
-    PixelariumImageViewCzi(const PixelariumImageViewCzi&) = delete;
-    PixelariumImageViewCzi(PixelariumImageViewCzi&&) = delete;
-    PixelariumImageViewCzi& operator=(PixelariumImageViewCzi&) = delete;
-    PixelariumImageViewCzi& operator=(PixelariumImageViewCzi&&) = delete;
-
-    void ShowImage() override;
-
-   private:
-    ImVec2 curr_dim_{};
-};
-}  // namespace pixelarium::render

lib/rendering/PixelariumImageViewDefault.cpp

@@ -1,50 +0,0 @@
-#include "PixelariumImageViewDefault.hpp"
-
-#include <format>
-
-#include "RenderHelpers.hpp"
-#include "imaging/IPixelariumImage.hpp"
-#include "imgui.h"
-/// @brief Displays the image in an ImGui window.
-///
-/// If the image is null, empty, or has an empty name, the function returns immediately.  Otherwise, it creates an ImGui
-/// window with a horizontal scrollbar and menu bar. The image is rendered using the CvMatRender object, resizing it to
-/// fit the available window space.  The raw and rendered dimensions are displayed below the image.
-void pixelarium::render::PixelariumImageViewDefault::ShowImage()
-{
-    if (!this->cached_image_ || this->is_dirty_)
-    {
-        this->cached_image_ = this->img_->TryGetImage();
-        this->is_dirty_ = false;
-    }
-
-    if (this->img_->Empty() || this->img_->type_ == imaging::ImageFileType::UNKNOWN || !cached_image_ ||
-        this->img_->Name().empty())
-    {
-        // do nothing
-        return;
-    }
-
-    ImGui::Begin(this->img_->Name().c_str(), &this->open_p,
-                 ImGuiWindowFlags_HorizontalScrollbar | ImGuiWindowFlags_MenuBar);
-
-    this->curr_dim_ = ImGui::GetContentRegionAvail();
-    auto new_dim = ImGui::GetContentRegionAvail();
-    auto texture =
-        dim_changed_p(this->curr_dim_, new_dim)
-            ? this->render_.Render(static_cast<size_t>(this->curr_dim_.x), static_cast<size_t>(this->curr_dim_.y))
-            : this->render_.Render();
-
-    this->curr_dim_ = new_dim;
-
-    ImVec2 dim(cached_image_->cols, cached_image_->rows);
-
-    ImGui::Image(reinterpret_cast<ImTextureID>(reinterpret_cast<void*>(texture)),
-                 aspect_const_dimensions(dim, new_dim));
-
-    ImGui::Separator();
-    ImGui::Text("%s", std::format("   Raw Dimensions W : {}, H: {}", dim.x, dim.y).c_str());
-    ImGui::Text("%s", std::format("Render Dimensions W : {}, H: {}", curr_dim_.x, curr_dim_.y).c_str());
-
-    ImGui::End();
-}

lib/rendering/PixelariumImageViewDefault.hpp

@@ -1,35 +0,0 @@
-#pragma once
-
-#include <memory>
-
-#include "imaging/IPixelariumImage.hpp"
-#include "imgui.h"
-#include "rendering/CvMatRender.hpp"
-#include "rendering/IPixelariumImageView.hpp"
-
-namespace pixelarium::render
-{
-class PixelariumImageViewDefault : public IPixelariumImageView
-{
-    using Image = imaging::IPixelariumImage;
-    using Render = render::CvMatRender;
-
-   public:
-    explicit PixelariumImageViewDefault(std::shared_ptr<Image> img)
-    {
-        img_ = img;
-        render_ = Render(img_);
-    }
-    PixelariumImageViewDefault() = delete;
-    PixelariumImageViewDefault(PixelariumImageViewDefault&) = delete;
-    PixelariumImageViewDefault(const PixelariumImageViewDefault&) = delete;
-    PixelariumImageViewDefault(PixelariumImageViewDefault&&) = delete;
-    PixelariumImageViewDefault& operator=(PixelariumImageViewDefault&) = delete;
-    PixelariumImageViewDefault& operator=(PixelariumImageViewDefault&&) = delete;
-
-    void ShowImage() override;
-
-   private:
-    ImVec2 curr_dim_{};
-};
-}  // namespace pixelarium::render

lib/resources/CMakeLists.txt

@@ -1,14 +1,17 @@
 set(RESOURCELIBNAME pixelariumresourcelib)
 
 set(RESOURCELIBSRC
-  resource.hpp
+  include/resource.hpp
   resource.cpp)
 
 add_library(${RESOURCELIBNAME} STATIC
   ${RESOURCELIBSRC})
 
+add_library(pixelarium::lib::resources_static ALIAS ${RESOURCELIBNAME})
+
 target_link_libraries(${RESOURCELIBNAME}
-  PRIVATE pixelariumimagelib)
+  PRIVATE pixelarium::lib::imaging_static)
 
 target_include_directories(${RESOURCELIBNAME}
-  PRIVATE ${CMAKE_SOURCE_DIR}/lib)
+  INTERFACE
+  PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)

lib/resources/include/resource.hpp

@@ -6,12 +6,13 @@
 #include <mutex>
 #include <unordered_map>
 
-#include "imaging/IPixelariumImage.hpp"
+#include "IPixelariumImage.hpp"
 
 namespace pixelarium::resources
 {
 using ResourceKey = size_t;
 
+/// @brief A dedicated exception to be thrown when a resource of an IResourcePool is empty.
 struct empty_resource_exception : public std::exception
 {
     empty_resource_exception() {};
@@ -22,16 +23,22 @@ struct empty_resource_exception : public std::exception
     std::string message_ = "Empty Resource";
 };
 
-
+/// @brief Abstract representation of a Resource.
+/// This is meant to be implemented by arbitrary explicit resource types and thus
+/// gives no contract other than the abstract type.
 struct IResource
 {
     virtual ~IResource() = default;
 };
 
+/// @brief Defines a concept for a resource type
+/// @tparam R  The resource template parameter
 template <typename R>
 concept ResT = requires(R& r) { static_cast<IResource&>(r); };
 
-template <typename ResT>
+/// @brief Defines an interface for a resource pool
+/// @tparam ResT  defines the resource type that is accepted by the pool
+template <typename ResT, class Data>
 class IResourcePool
 {
    public:
@@ -41,7 +48,7 @@ class IResourcePool
     virtual bool ModifyResource(ResourceKey id, std::unique_ptr<ResT> res) = 0;
     virtual bool DeleteResource(ResourceKey id) = 0;
     virtual void EnumerateResources(
-        const std::function<void(ResourceKey, size_t, const imaging::IPixelariumImage&)>& func) = 0;
+        const std::function<void(ResourceKey, size_t, const imaging::IPixelariumImage<Data>&)>& func) = 0;
     virtual size_t GetTotalSize() const = 0;
     virtual void Clear() = 0;
 };
@@ -51,7 +58,7 @@ class IResourcePool
 // reside with the =ResourcePool=!
 // In fact, the intention is, that there is no way back once the =ResourcePool= took ownership of an object.
 // Callers can get references, but no ownership. A caller might delete a resource though.
-class ImageResourcePool : public IResourcePool<imaging::IPixelariumImage>
+class ImageResourcePool : public IResourcePool<imaging::IPixelariumImageCvMat, cv::Mat>
 {
    public:
     ImageResourcePool() = default;
@@ -61,17 +68,17 @@ class ImageResourcePool : public IResourcePool<imaging::IPixelariumImage>
     ImageResourcePool& operator=(ImageResourcePool&) = delete;
     ImageResourcePool& operator=(ImageResourcePool&&) = delete;
 
-    std::weak_ptr<imaging::IPixelariumImage> GetResource(ResourceKey id) const override;
-    ResourceKey SetResource(std::unique_ptr<imaging::IPixelariumImage> res) override;
-    bool ModifyResource(ResourceKey id, std::unique_ptr<imaging::IPixelariumImage> res) override;
+    std::weak_ptr<imaging::IPixelariumImageCvMat> GetResource(ResourceKey id) const override;
+    ResourceKey SetResource(std::unique_ptr<imaging::IPixelariumImageCvMat> res) override;
+    bool ModifyResource(ResourceKey id, std::unique_ptr<imaging::IPixelariumImageCvMat> res) override;
     bool DeleteResource(ResourceKey id) override;
     void Clear() override { this->resources_.clear(); }
 
     void EnumerateResources(
-        const std::function<void(ResourceKey, size_t, const imaging::IPixelariumImage&)>& func) override;
+        const std::function<void(ResourceKey, size_t, const imaging::IPixelariumImage<cv::Mat>&)>& func) override;
 
     template <typename Callable>
-        requires std::invocable<Callable, ResourceKey, size_t, const imaging::IPixelariumImage&>
+        requires std::invocable<Callable, ResourceKey, size_t, const imaging::IPixelariumImageCvMat&>
     void Enumerate(Callable&& func) const
     {
         size_t idx{0};
@@ -84,7 +91,7 @@ class ImageResourcePool : public IResourcePool<imaging::IPixelariumImage>
     size_t GetTotalSize() const override { return resources_.size(); }
 
    private:
-    std::unordered_map<size_t, std::shared_ptr<imaging::IPixelariumImage>> resources_;
+    std::unordered_map<size_t, std::shared_ptr<imaging::IPixelariumImageCvMat>> resources_;
     std::mutex mut_;
 };
 }  // namespace pixelarium::resources

lib/resources/resource.cpp

@@ -5,7 +5,9 @@
 #include <functional>
 #include <mutex>
 
-using pixelarium::imaging::IPixelariumImage;
+#include "IPixelariumImage.hpp"
+
+using Image = pixelarium::imaging::IPixelariumImageCvMat;
 using namespace std;
 
 namespace
@@ -21,7 +23,7 @@ size_t GenerateId() { return id_.fetch_add(1, memory_order_relaxed); }
 /// @brief Retrieves a resource from the pool.
 /// @param id The ID of the resource to retrieve.
 /// @return A pointer to the resource if found, otherwise an empty optional.
-std::weak_ptr<IPixelariumImage> pixelarium::resources::ImageResourcePool::GetResource(ResourceKey id) const
+std::weak_ptr<Image> pixelarium::resources::ImageResourcePool::GetResource(ResourceKey id) const
 {
     auto search{this->resources_.find(id)};
     if (search == this->resources_.end()) return {};
@@ -32,7 +34,7 @@ std::weak_ptr<IPixelariumImage> pixelarium::resources::ImageResourcePool::GetRes
 /// @brief Sets a resource in the pool.
 /// @param res A unique pointer to the resource to set.
 /// @return The ID of the new resource.
-size_t pixelarium::resources::ImageResourcePool::SetResource(unique_ptr<IPixelariumImage> res)
+size_t pixelarium::resources::ImageResourcePool::SetResource(unique_ptr<Image> res)
 {
     if (res == nullptr)
     {
@@ -52,8 +54,7 @@ size_t pixelarium::resources::ImageResourcePool::SetResource(unique_ptr<IPixelar
 /// @param id The ID of the resource to update.
 /// @param res A unique pointer to the new resource.
 /// @return True if the resource was updated, false otherwise.
-bool pixelarium::resources::ImageResourcePool::ModifyResource(ResourceKey id,
-                                                              std::unique_ptr<imaging::IPixelariumImage> res)
+bool pixelarium::resources::ImageResourcePool::ModifyResource(ResourceKey id, std::unique_ptr<Image> res)
 {
     auto search{this->resources_.find(id)};
     if (search == this->resources_.end()) return false;
@@ -80,7 +81,7 @@ bool pixelarium::resources::ImageResourcePool::DeleteResource(ResourceKey id)
 /// @param func A function to call for each resource.  The function should accept the resource ID and a const reference
 /// to a PixelariumImage.
 void pixelarium::resources::ImageResourcePool::EnumerateResources(
-    const std::function<void(ResourceKey, size_t, const imaging::IPixelariumImage&)>& func)
+    const std::function<void(ResourceKey, size_t, const imaging::IPixelariumImage<cv::Mat>&)>& func)
 {
     size_t idx{0};
     for (const auto& e : this->resources_)

lib/utilities/CMakeLists.txt

@@ -1,12 +1,17 @@
 set(UTILSLIBNAME pixelariumutilslib)
 
 set(UTILSLIBSRC
-  ILog.hpp
-  SpdLogger.hpp
-  SpdLogger.cpp)
+  include/ILog.hpp
+  include/SpdLogger.hpp
+  include/PixelariumLogger.hpp
+  include/simple_thread_pool.hpp
+  SpdLogger.cpp
+  PixelariumLogger.cpp)
 
 add_library(${UTILSLIBNAME} STATIC ${UTILSLIBSRC})
 
+add_library(pixelarium::lib::utilities_static ALIAS ${UTILSLIBNAME})
+
 # won't work
 # target_compile_options(${UTILSLIBNAME}
 #   PRIVATE
@@ -14,7 +19,9 @@ add_library(${UTILSLIBNAME} STATIC ${UTILSLIBSRC})
 #   "$<$<CXX_COMPILER_ID:MSVC>:/utf-8>")
 
 target_include_directories(${UTILSLIBNAME}
+  INTERFACE
+  PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include
   PRIVATE ${spdlog_DIR}/include)
 
 target_link_libraries(${UTILSLIBNAME}
-  PRIVATE spdlog::spdlog_header_only)
+  PUBLIC spdlog::spdlog_header_only)

lib/utilities/ILog.hpp

@@ -1,26 +0,0 @@
-#pragma once
-#include <string>
-
-namespace pixelarium::utils::log
-{
-enum class LogLevel
-{
-    Trace = 1 << 0,
-    Debug = 1 << 1,
-    Info = 1 << 2,
-    Warn = 1 << 3,
-    Error = 1 << 4,
-};
-class ILog
-{
-   public:
-    virtual void Info(const std::string& msg) const = 0;
-    virtual void Debug(const std::string& msg) const = 0;
-    virtual void Warn(const std::string& msg) const = 0;
-    virtual void Error(const std::string& msg) const = 0;
-    virtual void ChangeLevel(LogLevel lvl) const = 0;
-
-    virtual ~ILog() {}
-};
-
-}  // namespace pixelarium::utils::log

lib/utilities/PixelariumLogger.cpp

@@ -0,0 +1,73 @@
+#include "PixelariumLogger.hpp"
+
+#include <chrono>
+#include <fstream>
+#include <memory>
+#include <ostream>
+#include <stdexcept>
+
+using namespace pixelarium::utils::log;
+
+struct PixelariumLogger::LogStream
+{
+    LogStream(const std::string& sink)
+    {
+        out_stream_ = std::ofstream(sink, std::ios::app);
+        if (!out_stream_)
+        {
+            throw std::runtime_error("Failed to open log stream");
+        }
+    }
+
+    ~LogStream()
+    {
+        if (out_stream_.is_open())
+        {
+            out_stream_.close();
+        }
+    }
+
+    LogStream& operator<<(const std::string& str)
+    {
+        this->out_stream_ << str;
+        return *this;
+    }
+
+   private:
+    std::ofstream out_stream_;
+};
+
+PixelariumLogger::PixelariumLogger(const std::string& name, const std::string& file_sink)
+    : name_(name), file_sink_(file_sink)
+{
+    log_stream_ = std::make_unique<LogStream>(file_sink_);
+}
+
+PixelariumLogger::~PixelariumLogger() = default;
+
+auto PixelariumLogger::Write(LogLevel lvl, const std::string& msg) const -> void
+{
+    if (lvl < this->level_)
+    {
+        return;
+    }
+
+    auto now = std::chrono::system_clock::now();
+    auto time_t = std::chrono::system_clock::to_time_t(now);
+    std::tm tm;
+#ifdef _WIN32
+    localtime_s(&tm, &time_t);
+#else
+    localtime_r(&time_t, &tm);
+#endif
+
+    auto ms = std::chrono::duration_cast<std::chrono::milliseconds>(now.time_since_epoch()) % 1000;
+
+    auto timestamp = std::format("{:04}-{:02}-{:02} {:02}:{:02}:{:02}.{:03}", tm.tm_year + 1900, tm.tm_mon + 1,
+                                 tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec, ms.count());
+
+    {
+        std::lock_guard<std::mutex> guard(mutex_);
+        *log_stream_ << std::format("[{}] [{}] [{}] {}\n", timestamp, name_, LogLevelToString(lvl), msg);
+    }
+}

lib/utilities/SpdLogger.cpp

@@ -30,15 +30,15 @@ void SpdLogger::ChangeLevel(LogLevel lvl) const
     {
         switch (l)
         {
-            case LogLevel::Trace:
+            case LogLevel::kTrace:
                 return "Trace";
-            case LogLevel::Debug:
+            case LogLevel::kDebug:
                 return "Debug";
-            case LogLevel::Info:
+            case LogLevel::kInfo:
                 return "Info";
-            case LogLevel::Warn:
+            case LogLevel::kWarn:
                 return "Warn";
-            case LogLevel::Error:
+            case LogLevel::kError:
                 return "Error";
             default:
                 return "Not Found";
@@ -47,23 +47,23 @@ void SpdLogger::ChangeLevel(LogLevel lvl) const
 
     switch (lvl)
     {
-        case LogLevel::Trace:
+        case LogLevel::kTrace:
             this->logger_->set_level(spdlog::level::trace);
             spdlog::flush_on(spdlog::level::trace);
             break;
-        case LogLevel::Info:
+        case LogLevel::kInfo:
             this->logger_->set_level(spdlog::level::info);
             spdlog::flush_on(spdlog::level::info);
             break;
-        case LogLevel::Warn:
+        case LogLevel::kWarn:
             this->logger_->set_level(spdlog::level::warn);
             spdlog::flush_on(spdlog::level::warn);
             break;
-        case LogLevel::Error:
+        case LogLevel::kError:
             this->logger_->set_level(spdlog::level::err);
             spdlog::flush_on(spdlog::level::err);
             break;
-        case LogLevel::Debug:
+        case LogLevel::kDebug:
         default:
             this->logger_->set_level(spdlog::level::debug);
             spdlog::flush_on(spdlog::level::debug);

lib/utilities/include/ILog.hpp

@@ -0,0 +1,49 @@
+#pragma once
+#include <string>
+
+#ifdef _WIN32
+#define __PRETTY_FUNCTION__ __FUNCTION__
+#endif
+
+namespace pixelarium::utils::log
+{
+enum class LogLevel
+{
+    kTrace = 1 << 0,
+    kDebug = 1 << 1,
+    kInfo = 1 << 2,
+    kWarn = 1 << 3,
+    kError = 1 << 4,
+};
+
+constexpr auto LogLevelToString(LogLevel lvl) -> std::string
+{
+    switch (lvl)
+    {
+        case LogLevel::kTrace:
+            return "Trace";
+        case LogLevel::kDebug:
+            return "Debug";
+        case LogLevel::kInfo:
+            return "Info";
+        case LogLevel::kWarn:
+            return "Warning";
+        case LogLevel::kError:
+            return "Error";
+    }
+}
+
+/// @brief Interface for logging implementations.
+class ILog
+{
+   public:
+    virtual void Info(const std::string& msg) const = 0;
+    virtual void Debug(const std::string& msg) const = 0;
+    virtual void Warn(const std::string& msg) const = 0;
+    virtual void Error(const std::string& msg) const = 0;
+    virtual void ChangeLevel(LogLevel lvl) const = 0;
+
+    virtual ~ILog() {}
+};
+
+}  // namespace pixelarium::utils::log

lib/utilities/include/PixelariumLogger.hpp

@@ -0,0 +1,36 @@
+#pragma once
+
+#include <memory>
+#include <mutex>
+#include <string>
+
+#include "ILog.hpp"
+
+namespace pixelarium::utils::log
+{
+class PixelariumLogger : public ILog
+{
+   private:
+    struct LogStream;
+
+   public:
+    explicit PixelariumLogger(const std::string& name, const std::string& file_sink);
+    ~PixelariumLogger();
+
+    void Info(const std::string& msg) const override { this->Write(LogLevel::kInfo, msg); }
+    void Debug(const std::string& msg) const override { this->Write(LogLevel::kDebug, msg); }
+    void Warn(const std::string& msg) const override { this->Write(LogLevel::kWarn, msg); }
+    void Error(const std::string& msg) const override { this->Write(LogLevel::kError, msg); }
+    void ChangeLevel(LogLevel lvl) const override { this->level_ = lvl; }
+
+   private:
+    void Write(LogLevel, const std::string&) const;
+
+   private:
+    std::mutex mutable mutex_;
+    std::string name_;
+    std::string file_sink_;
+    std::unique_ptr<LogStream> log_stream_{};
+    LogLevel mutable level_{LogLevel::kDebug};
+};
+}  // namespace pixelarium::utils::log

lib/utilities/include/SpdLogger.hpp

@@ -8,6 +8,8 @@
 #include "ILog.hpp"
 namespace pixelarium::utils::log
 {
+/// @brief Implements ILog using the spdlog library
+/// see https://github.com/gabime/spdlog
 class SpdLogger : public ILog
 {
    public:

lib/utilities/include/simple_thread_pool.hpp

@@ -0,0 +1,128 @@
+#pragma once
+
+#include <atomic>
+#include <condition_variable>
+#include <cstddef>
+#include <functional>
+#include <mutex>
+#include <queue>
+#include <thread>
+#include <vector>
+
+namespace pixelarium::utils
+{
+template <size_t N>
+class simple_thread_pool
+{
+   public:
+    simple_thread_pool()
+    {
+        static_assert(N > 0, "Pool must have at least one thread.");
+        for (size_t i{0}; i < N; ++i)
+        {
+            workers_.emplace_back(
+                [this]()
+                {
+                    while (true)
+                    {
+                        std::function<void()> job;
+                        {
+                            std::unique_lock<std::mutex> lck(thread_mutex_);
+
+                            cv_.wait(lck, [this]() -> bool { return shutdown_ || !task_queue_.empty(); });
+
+                            if (shutdown_ && task_queue_.empty()) return;
+
+                            job = std::move(task_queue_.front());
+                            task_queue_.pop();
+                            ++running_tasks_;
+                        }
+
+                        job();
+                        --running_tasks_;
+                    }
+                });
+        }
+    }
+
+    simple_thread_pool(simple_thread_pool&) = delete;
+    simple_thread_pool(const simple_thread_pool&) = delete;
+    simple_thread_pool(simple_thread_pool&&) = delete;
+    simple_thread_pool& operator=(simple_thread_pool&) = delete;
+    simple_thread_pool& operator=(simple_thread_pool&&) = delete;
+    ~simple_thread_pool()
+    {
+        {
+            std::unique_lock<std::mutex> lck(thread_mutex_);
+            shutdown_ = true;
+        }
+
+        cv_.notify_all();
+        for (auto& th : workers_)
+        {
+            th.join();
+        }
+    }
+
+   public:
+    template <typename Callable>
+        requires std::invocable<Callable>
+    auto enqueue(Callable&& fun) -> void
+    {
+        {
+            std::unique_lock<std::mutex> lck(thread_mutex_);
+            task_queue_.emplace(std::forward<Callable>(fun));
+        }
+
+        cv_.notify_one();
+    }
+
+    [[nodiscard]]
+    decltype(auto) RunningTasks() const
+    {
+        return running_tasks_.load();
+    }
+
+    decltype(auto) Joinable() const
+    {
+        std::unique_lock<std::mutex> lck(thread_mutex_);
+
+        return task_queue_.empty() && RunningTasks() == 0;
+    }
+
+   private:
+    std::vector<std::thread> workers_;
+    std::condition_variable cv_;
+    std::mutex mutable thread_mutex_;
+    std::queue<std::function<void()>> task_queue_;
+    bool shutdown_{false};
+    std::atomic_size_t running_tasks_{0};
+};
+
+class pixelarium_pool
+{
+   public:
+    [[nodiscard]]
+    static decltype(auto) RunningTasks()
+    {
+        return pixelarium_pool::instance().RunningTasks();
+    }
+
+    static decltype(auto) Joinable() { return pixelarium_pool::instance().Joinable(); }
+
+    template <typename Callable>
+        requires std::invocable<Callable>
+    static auto enqueue(Callable&& fun) -> void
+    {
+        pixelarium_pool::instance().enqueue(std::forward<Callable>(fun));
+    }
+
+   private:
+    static constexpr auto kThreadCount{20};
+    static simple_thread_pool<kThreadCount>& instance()
+    {
+        static simple_thread_pool<kThreadCount> pixelarium_pool_instance;
+        return pixelarium_pool_instance;
+    }
+};
+}  // namespace pixelarium::utils

src/main.cpp

@@ -1,26 +0,0 @@
-#include <memory>
-
-#include "DefaultApp.hpp"
-#include "resources/resource.hpp"
-#include "utilities/ILog.hpp"
-#include "utilities/SpdLogger.hpp"
-
-int main(int argc, char** argv)
-{
-    using namespace pixelarium;
-    using namespace std;
-    unique_ptr<utils::log::ILog> logger;
-#ifdef _WIN32
-    logger = make_unique<utils::log::SpdLogger>(string(getenv("APPDATA")) + "/pixelarium/logfile.log", "default");
-#else
-    logger = make_unique<utils::log::SpdLogger>(std::string(getenv("HOME")) + "/.cache/pixelarium/log.log", "default");
-#endif
-    logger->Info(std::format("{}: Starting Application {}", __FUNCTION__, "Pixelarium"));
-
-    logger->ChangeLevel(utils::log::LogLevel::Debug);
-    auto image_pool{std::make_unique<resources::ImageResourcePool>()};
-
-    pixelarium::ui::DefaultApp app = pixelarium::ui::DefaultApp(*logger, *image_pool);
-
-    app.Start();
-}

tests/CMakeLists.txt

@@ -1,17 +1,13 @@
-include(${PROJECT_SOURCE_DIR}/cmake/googletest.cmake)
+# this will trigger the FetchContent
+include(testgoogle)
 
 add_executable(libpixelarium_UnitTests
-  lib/resources/test_resource.cpp)
-
-target_include_directories(libpixelarium_UnitTests
-  PUBLIC ${PROJECT_SOURCE_DIR}/lib
-  PUBLIC ${OpenCV_INCLUDE_DIRS}
-)
-
+  lib/resources/test_resource.cpp
+  lib/utilities/test_simple_thread_pool.cpp)
 
 target_link_libraries(libpixelarium_UnitTests
-  pixelariumresourcelib
-  pixelariumimagelib
+  pixelarium::lib::resources_static
+  pixelarium::lib::imaging_static
   GTest::gtest_main
   GTest::gmock)
 

tests/lib/resources/test_resource.cpp

@@ -2,20 +2,21 @@
 
 #include <algorithm>
 
-#include "resources/resource.hpp"
+#include "IPixelariumImage.hpp"
+#include "resource.hpp"
 
 namespace
 {
 
 // A Mock implementation for tests requiring _any_ instance of a IPixelariumImage
-class DummyImage : public pixelarium::imaging::IPixelariumImage
+class DummyImage : public pixelarium::imaging::IPixelariumImageCvMat
 {
    public:
-    std::unique_ptr<cv::Mat> TryGetImage() override { return {}; }
+    std::optional<cv::Mat> TryGetImage() override { return {}; }
 
-    std::unique_ptr<cv::Mat> TryGetImage(const pixelarium::imaging::IImageQuery&) override { return {}; }
+    std::optional<cv::Mat> TryGetImage(const pixelarium::imaging::IImageQuery&) override { return {}; }
 
-    std::vector<std::unique_ptr<cv::Mat>> TryGetImages(const pixelarium::imaging::IImageQuery&) override { return {}; }
+    std::vector<std::optional<cv::Mat>> TryGetImages(const pixelarium::imaging::IImageQuery&) override { return {}; }
 
     std::string Name() const noexcept override { return {}; }
 
@@ -43,7 +44,7 @@ TEST(ImageResourcePoolTest, SetWrappedRawPointerGet)
 {
     ImageResourcePool pool;
     auto img = new DummyImage();
-    auto id = pool.SetResource(std::unique_ptr<pixelarium::imaging::IPixelariumImage>(img));
+    auto id = pool.SetResource(std::unique_ptr<pixelarium::imaging::IPixelariumImageCvMat>(img));
     auto res = pool.GetResource(id);
     auto res_img = res.lock();
     EXPECT_NE(res_img, nullptr);
@@ -95,7 +96,7 @@ TEST(ImageResourcePoolTest, EnumerateResources)
     auto id2 = pool.SetResource(std::make_unique<DummyImage>());
     std::vector<size_t> found_ids{};
 
-    pool.EnumerateResources([&found_ids](size_t id, size_t, const pixelarium::imaging::IPixelariumImage&)
+    pool.EnumerateResources([&found_ids](size_t id, size_t, const pixelarium::imaging::IPixelariumImage<cv::Mat>&)
                             { found_ids.push_back(id); });
 
     EXPECT_EQ(found_ids.size(), 2);
@@ -110,7 +111,7 @@ TEST(ImageResourcePoolTest, TemplatedEnumerate)
     auto id2 = pool.SetResource(std::make_unique<DummyImage>());
     std::vector<size_t> found_ids{};
 
-    pool.Enumerate([&found_ids](size_t id, size_t, const pixelarium::imaging::IPixelariumImage&)
+    pool.Enumerate([&found_ids](size_t id, size_t, const pixelarium::imaging::IPixelariumImage<cv::Mat>&)
                    { found_ids.push_back(id); });
 
     EXPECT_EQ(found_ids.size(), 2);

tests/lib/utilities/test_simple_thread_pool.cpp

@@ -0,0 +1,55 @@
+#include <gtest/gtest.h>
+
+#include <chrono>
+#include <thread>
+#include <vector>
+
+#include "simple_thread_pool.hpp"
+
+TEST(SimpleThreadPoolTest, MutatesFromDifferentThread)
+{
+    using namespace std::chrono_literals;
+    using namespace pixelarium::utils;
+    std::mutex mut;
+    constexpr auto vecsize{10};
+    std::vector<int> mutation_vector(vecsize, 0);
+
+    auto mutate = [&mutation_vector](int val, int loc) -> void { mutation_vector.at(loc) = val; };
+
+    for (auto i{0}; i < vecsize; ++i)
+    {
+        pixelarium_pool::enqueue(
+            [&mutate, i]()
+            {
+                const auto wait = std::chrono::milliseconds(i);
+                std::this_thread::sleep_for(wait);
+                mutate(i, i);
+            });
+    }
+
+    // wait until each spawned task finished
+    while (!pixelarium_pool::Joinable()) std::this_thread::sleep_for(5ms);
+
+    EXPECT_EQ(mutation_vector.size(), vecsize);
+    for (auto i{0}; i < vecsize; ++i)
+    {
+        EXPECT_EQ(mutation_vector.at(i), i);
+    }
+}
+
+// TEST(SimpleThreadPoolTest, ZeroThreads)
+// {
+//     using namespace pixelarium::utils;
+//     // Creating a thread pool with 0 threads should not throw an exception
+//     // and should be joinable immediately.
+//     simple_thread_pool<0> pool;
+//     EXPECT_TRUE(pool.Joinable());
+
+//     // Enqueuing a task on a 0-thread pool should not crash.
+//     // The task will never run, but the enqueue operation should be valid.
+//     pool.enqueue([]() {});
+//     EXPECT_FALSE(pool.Joinable()); // Now it's not joinable because there's a task
+//     EXPECT_EQ(pool.RunningTasks(), 0); // No tasks are running
+
+//     // Destructor should also handle the 0-thread case gracefully.
+// }