Proper image rendering ux (#5)

* can draw from selection

* add light-weight render manager to render many images simultaneously

* [debug me] currently the image close button does not do

* the unselected image can be closed now

* can close images and manually open them on demand

* cosmetic

* image view stuff in render subdirectory

* cosmetic

* generate docs

* review

windows support

some cosmetics

💅 and pin libCZI module

CMakeLists.txt

@@ -19,11 +19,13 @@ message(STATUS "GLFW:\t" ${glfw3_module_DIR})
 message(STATUS "PFD:\t\t" ${pfd_DIR})
 message(STATUS "SPDLOG:\t" ${spdlog_DIR})
 
-if (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
-  set(CMAKE_CXX_FLAGS "/std:c++20 /Zi /EHsc")
-endif()
-if (WIN32 AND NOT CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
-  set(CMAKE_CXX_FLAGS "-Wall -Wextra -g --std=c++20")
+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")
+  else()
+    set(CMAKE_CXX_FLAGS "-Wall -Wextra -g --std=c++20")
+  endif()
 endif()
 if(UNIX)
   set(CMAKE_CXX_FLAGS "-Wall -Wextra -g --std=c++20")
@@ -40,8 +42,6 @@ add_subdirectory(lib)
 
 set(SRC
   src/MyApp.cpp
-  src/views/PixelariumImageView.cpp
-  src/viewmodels/ImageViewFactory.cpp
   src/main.cpp)
 
 #====================

CMakePresets.json

@@ -8,6 +8,7 @@
   "configurePresets": [
     {
       "name": "default",
+      "hidden": true,
       "generator": "Ninja",
       "binaryDir": "build",
       "cacheVariables": {
@@ -20,12 +21,14 @@
     {
       "name": "clang-release",
       "inherits": "default",
+      "binaryDir": "build/clang-release",
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Release"
       }
     },
     {
       "name": "clang-debug",
+      "binaryDir": "build/clang-debug",
       "inherits": "default",
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Debug"
@@ -34,6 +37,7 @@
     {
       "name": "gcc-release",
       "inherits": "default",
+      "binaryDir": "build/gcc-release",
       "cacheVariables": {
         "CMAKE_C_COMPILER": "gcc",
         "CMAKE_CXX_COMPILER": "g++",
@@ -43,6 +47,7 @@
     {
       "name": "gcc-debug",
       "inherits": "default",
+      "binaryDir": "build/gcc-debug",
       "cacheVariables": {
         "CMAKE_C_COMPILER": "gcc",
         "CMAKE_CXX_COMPILER": "g++",
@@ -53,7 +58,8 @@
   "buildPresets": [
     {
       "name": "default",
-      "configurePreset": "default",
+      "hidden": true,
+      "configurePreset": "clang-debug",
       "jobs": 10
     },
     {

cmake/libCZI.cmake

@@ -3,7 +3,7 @@ include(FetchContent)
 FetchContent_Declare(
   libCZI
   GIT_REPOSITORY https://github.com/ZEISS/libczi.git
-  GIT_TAG        origin/main
+  GIT_TAG        593ee17587214358c535bd036473b1b62945e637
 )
 
 if(NOT libCZI_POPULATED)

lib/app/AppGLFW.cpp

@@ -1,15 +1,29 @@
 #include "AppGLFW.hpp"
 
+#include "app_resources_default.h"
 #include "imgui.h"
 #include "imgui_impl_glfw.h"
 #include "imgui_impl_opengl3.h"
-#include "app_resources_default.h"
 
+/// @brief GLFW error callback function.
+/// @param error The error code.
+/// @param description A description of the error.
 static void glfw_error_callback(int error, const char* description)
 {
     fprintf(stderr, "GLFW Error %d: %s\n", error, description);
 }
 
+/// @brief Initializes the main application window using GLFW.
+///
+/// This function sets up the GLFW error callback, initializes GLFW,
+/// selects appropriate OpenGL and GLSL versions based on platform,
+/// creates the main application window, sets up the OpenGL context,
+/// enables vsync, and initializes the Dear ImGui context, style, and
+/// platform/renderer backends.  It uses the primary monitor's workarea
+/// to determine the screen resolution but creates a window of a fixed size (1200x800).
+///
+/// @return void.  The function returns void and uses error handling internally to manage GLFW and window creation
+/// failures.  The application may continue to run in a failed state, but the window will not be initialized.
 void pixelarium::application::AppGLFW::InitMainWindow()
 {
     glfwSetErrorCallback(glfw_error_callback);
@@ -95,6 +109,8 @@ void pixelarium::application::AppGLFW::InitMainWindow()
     ImGui_ImplOpenGL3_Init(glsl_version);
 }
 
+/// @brief Main application loop.  This function handles window events, rendering, and ImGui integration.
+/// @return 0 if the application closes successfully.
 int pixelarium::application::AppGLFW::RunLoop()
 {
     ImGuiIO& io = ImGui::GetIO();
@@ -141,6 +157,10 @@ int pixelarium::application::AppGLFW::RunLoop()
     return 0;
 }
 
+/// @brief Creates and displays the main menu bar.
+///
+/// This function constructs the application's main menu bar using ImGui.  It includes a log level selector
+/// and calls other functions to populate additional menu bar sections.
 void pixelarium::application::AppGLFW::MenuBar()
 {
     if (ImGui::BeginMainMenuBar())
@@ -179,6 +199,7 @@ void pixelarium::application::AppGLFW::MenuBar()
     }
 }
 
+/// @brief Allows the user to select the log level via a combo box.
 void pixelarium::application::AppGLFW::LogLevelSelect()
 {
     if (ImGui::BeginCombo(LOGLEVELSELECT, LOGLEVELS[log_level_].data()))

lib/imaging/PixelariumImage.cpp

@@ -13,5 +13,6 @@ pixelarium::imaging::PixelariumImage::PixelariumImage(const std::string& uri)
         throw std::runtime_error(std::format("File not {} found", uri));
     }
 
+    this->uri_ = std::filesystem::path(uri);
     this->img_ = std::make_unique<cv::Mat>(cv::imread(uri));
 }

lib/imaging/PixelariumImage.hpp

@@ -1,45 +1,85 @@
 #pragma once
 
+#include <filesystem>
+#include <functional>
 #include <memory>
 #include <opencv2/core/mat.hpp>
 #include <string>
 
 namespace pixelarium::imaging
 {
+using AccessorFunctor = std::function<void(const std::string&, void*, int*)>;
+
+enum class ImageFileType
+{
+    ABSRACT = 0,
+    PNG = 1,
+    JPG = 2,
+    CZI = 3,
+};
+/// @brief This aims to be a generic image abstraction
+/// meant for codec specific implementation.
+
+/// Todo: the above implies that most of the below implementations don't make sense for this class (c.f. cv::Mat
+/// generation et.al.)
 class PixelariumImage
 {
    public:
+    // get back the defaults
+    // this means, that there has to be and API option to set
+    // a resource which should trigger some sort of action
+    // after setting
 
     explicit PixelariumImage(const std::string& uri);
 
-    // get back the defaults
     PixelariumImage() = default;
     PixelariumImage(const PixelariumImage& other)
     {
         // be ware!!
         // we make a copy of the image data here!
         img_ = std::make_unique<cv::Mat>(*other.img_);
+        uri_ = other.uri_;
     };
-    PixelariumImage(PixelariumImage&& other) noexcept
-        : img_(std::move(other.img_)) {}
-    // requires a copy ctor which we don't have
+    PixelariumImage(PixelariumImage&& other) noexcept : img_(std::move(other.img_)) {}
     PixelariumImage& operator=(const PixelariumImage& other) = delete;
     PixelariumImage& operator=(PixelariumImage&& other) noexcept
     {
         if (this != &other)
         {
             img_ = std::move(other.img_);
+            uri_ = other.uri_;
         }
 
         return *this;
     }
+    // this should probably vanish as it makes no sense
+    // for multidimensional images (more than one frame)
+    // -> we need some sort of accessor functionality
 
     ~PixelariumImage() = default;
 
     const cv::Mat& GetImage() const { return *this->img_.get(); }
 
+    const std::string Name() const noexcept
+    {
+        if (!this->uri_.empty())
+        {
+            return this->uri_.filename().string();
+        }
+
+        return {};
+    }
+
+    bool Empty() const noexcept { return this->img_->empty(); }
+
+    static ImageFileType Type() { return PixelariumImage::type_; }
+
    protected:
     std::unique_ptr<cv::Mat> img_;
+
+    std::filesystem::path uri_;
+
+    static ImageFileType type_;
 };
 
 }  // namespace pixelarium::imaging

lib/rendering/CMakeLists.txt

@@ -1,7 +1,10 @@
 set(RENDERLIBNAME pixelariumrenderlib)
 
 set(RENDERLIBSRC
-  CvMatRender.cpp)
+  CvMatRender.cpp
+  RenderImageManager.cpp
+  PixelariumImageView.cpp
+  ImageViewFactory.cpp)
 
 add_library(${RENDERLIBNAME} STATIC
   ${RENDERLIBSRC})
@@ -10,4 +13,5 @@ target_link_libraries(${RENDERLIBNAME}
   PRIVATE pixelariumimagelib)
 
 target_include_directories(${RENDERLIBNAME}
-  PRIVATE ${CMAKE_SOURCE_DIR}/lib)
+  PRIVATE ${CMAKE_SOURCE_DIR}/lib
+  PRIVATE ${imgui_DIR})

lib/rendering/ImageViewFactory.cpp

@@ -0,0 +1,22 @@
+#include "ImageViewFactory.hpp"
+
+#include <memory>
+#include <optional>
+
+/// @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::PixelariumImageView> pixelarium::render::ImageViewFactory::RenderImage(
+    size_t image_id)
+{
+    auto img{this->image_pool_.GetResource(image_id)};
+
+    if (!img.has_value() || img.value()->Empty())
+    {
+        return nullptr;
+    }
+
+    // beware: here we copy the actual image resource over to the new image
+    return std::make_unique<PixelariumImageView>(std::make_shared<Image>(*img.value()));
+}
+

lib/rendering/ImageViewFactory.hpp

@@ -1,9 +1,9 @@
 #pragma once
 
-#include "PixelariumImage.hpp"
+#include "PixelariumImageView.hpp"
+#include "imaging/PixelariumImage.hpp"
 #include "resources/resource.hpp"
-#include "views/PixelariumImageView.hpp"
-namespace pixelarium::ui
+namespace pixelarium::render
 {
 class ImageViewFactory
 {
@@ -13,15 +13,9 @@ class ImageViewFactory
    public:
     explicit ImageViewFactory(Pool& pool) : image_pool_(pool) {}
 
-    [[nodiscard("Image Id is ignored")]]
-    size_t AddImage(std::unique_ptr<imaging::PixelariumImage> res) const noexcept
-    {
-        return image_pool_.SetResource(std::move(res));
-    }
-
     std::unique_ptr<PixelariumImageView> RenderImage(size_t id);
 
    private:
     Pool& image_pool_;
 };
-}  // namespace pixelarium::ui
+}  // namespace pixelarium::render

lib/rendering/PixelariumImageView.cpp

@@ -0,0 +1,70 @@
+#include "PixelariumImageView.hpp"
+
+#include <format>
+
+#include "imgui.h"
+
+/// @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.
+static bool 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))
+    {
+        return true;
+    }
+
+    return false;
+}
+
+/// @brief Calculates dimensions to maintain aspect ratio.
+/// @param img The input image.
+/// @param curr_dim The current dimensions.
+/// @return The calculated dimensions maintaining aspect ratio.
+ImVec2 aspect_const_dimensions(const pixelarium::imaging::PixelariumImage& img, const ImVec2& curr_dim)
+{
+    const auto w_fact = (static_cast<float>(curr_dim.x) / img.GetImage().cols);
+    const auto h_fact = (static_cast<float>(curr_dim.y) / img.GetImage().rows);
+
+    const auto fact = w_fact < h_fact ? w_fact : h_fact;
+
+    return ImVec2(img.GetImage().cols * fact, img.GetImage().rows * fact);
+}
+
+/// @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::PixelariumImageView::ShowImage()
+{
+    if (this->img_ == nullptr || this->img_->Empty() || this->img_->Name().empty())
+    {
+        // do nothing
+        return;
+    }
+
+    ImGui::Begin(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(this->img_->GetImage().cols, this->img_->GetImage().rows);
+
+    ImGui::Image(reinterpret_cast<ImTextureID>(reinterpret_cast<void*>(texture)),
+                 aspect_const_dimensions(*this->img_, 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/PixelariumImageView.hpp

@@ -2,11 +2,11 @@
 
 #include <memory>
 
-#include "PixelariumImage.hpp"
+#include "imaging/PixelariumImage.hpp"
 #include "imgui.h"
 #include "rendering/CvMatRender.hpp"
 
-namespace pixelarium::ui
+namespace pixelarium::render
 {
 class PixelariumImageView
 {
@@ -22,13 +22,14 @@ class PixelariumImageView
     PixelariumImageView& operator=(PixelariumImageView&) = delete;
     PixelariumImageView& operator=(PixelariumImageView&&) = delete;
 
-    void ToggleView(bool target) { open_p = target; }
+    // void ToggleView(bool target) { open_p = target; }
+    const bool* GetStatus() const noexcept { return &this->open_p; }
     void ShowImage();
 
    private:
     const std::shared_ptr<Image> img_;
     Render render_;
-    bool open_p{false};
+    bool open_p{true};
     ImVec2 curr_dim_{};
 };
-}  // namespace pixelarium::ui
+}  // namespace pixelarium::render

lib/rendering/RenderImageManager.cpp

@@ -0,0 +1,76 @@
+#include "RenderImageManager.hpp"
+
+#include <format>
+
+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()
+{
+    for (const auto& key : keys_to_delete_)
+    {
+        this->Remove(key);
+    }
+
+    keys_to_delete_.clear();
+}
+
+/// @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)
+{
+    this->log_.Debug(std::format("{} marking key: \"{}\" for deletion.", __PRETTY_FUNCTION__, key));
+    lock_guard<mutex> guard(this->mut_);
+    keys_to_delete_.insert(key);
+}
+
+/// @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 remove_state{false};
+    this->log_.Debug(std::format("{} removing key: \"{}\" from renderlist.", __PRETTY_FUNCTION__, key));
+    {
+        lock_guard<mutex> guard(this->mut_);
+        remove_state = this->render_image_map_.erase(key) == 1;
+    }
+
+    return remove_state;
+}
+
+/// @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
+{
+    // 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)
+    {
+        return;
+    }
+
+    this->log_.Debug(std::format("{}: adding key: \"{}\" to renderlist.", __PRETTY_FUNCTION__, key));
+
+    lock_guard<mutex> guard(this->mut_);
+    // clang-format off
+        this->render_image_map_.insert(
+            {
+                key,
+                RenderImageStateWrapper
+                {
+                    .view{ std::move(current_view) },
+                    .show_state = current_view->GetStatus(),
+                }
+            }
+            );
+    // clang-format on
+}
+
+/// @brief Clears all render images from the manager.
+/// @note This function is noexcept.
+void pixelarium::render::RenderImageManager::Clear() noexcept { this->render_image_map_.clear(); }

lib/rendering/RenderImageManager.hpp

@@ -0,0 +1,64 @@
+#pragma once
+#include <memory>
+#include <mutex>
+#include <unordered_map>
+#include <unordered_set>
+
+#include "ImageViewFactory.hpp"
+#include "PixelariumImageView.hpp"
+#include "resources/resource.hpp"
+#include "utilities/ILog.hpp"
+
+// This is intended as an additional abstraction
+// aggregating views that should be rendered (or not)
+namespace pixelarium::render
+{
+struct RenderImageStateWrapper
+{
+    std::unique_ptr<PixelariumImageView> view;
+    const bool* show_state;
+};
+
+class RenderImageManager
+{
+    using Pool = resources::ImageResourcePool;
+
+   public:
+    explicit RenderImageManager(Pool& pool, const utils::log::ILog& log)
+        : view_factory_(std::make_unique<ImageViewFactory>(pool)), log_(log)
+    {
+    }
+
+    void Clear() noexcept;
+
+    void Add(resources::ResourceKey key) noexcept;
+
+    bool Remove(resources::ResourceKey key) noexcept;
+
+    // can't be const because func mutates the state
+    template <typename Callable>
+        requires std::invocable<Callable, resources::ResourceKey, RenderImageStateWrapper&>
+    void Enumerate(Callable&& func)
+    {
+        for (auto& [key, val] : this->render_image_map_)
+        {
+            if (val.view != nullptr)
+            {
+                func(key, val);
+            }
+        }
+    }
+
+    void MarkForDeletion(resources::ResourceKey key);
+
+    void UpdateCollection();
+
+   private:
+    std::unordered_map<resources::ResourceKey, RenderImageStateWrapper> render_image_map_;
+    std::unique_ptr<ImageViewFactory> view_factory_;
+    std::mutex mut_;
+    std::unordered_set<resources::ResourceKey> keys_to_delete_;
+
+    const utils::log::ILog& log_;
+};
+}  // namespace pixelarium::render

lib/resources/resource.cpp

@@ -1,7 +1,9 @@
 #include "resource.hpp"
 
 #include <atomic>
+#include <cstddef>
 #include <functional>
+#include <mutex>
 #include <optional>
 
 using pixelarium::imaging::PixelariumImage;
@@ -20,7 +22,7 @@ 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::optional<const PixelariumImage*> pixelarium::resources::ImageResourcePool::GetResource(size_t id) const
+std::optional<const PixelariumImage*> pixelarium::resources::ImageResourcePool::GetResource(ResourceKey id) const
 {
     auto search{this->resources_.find(id)};
     if (search == this->resources_.end()) return std::nullopt;
@@ -34,7 +36,10 @@ std::optional<const PixelariumImage*> pixelarium::resources::ImageResourcePool::
 size_t pixelarium::resources::ImageResourcePool::SetResource(unique_ptr<PixelariumImage> res)
 {
     auto key{::GenerateId()};
-    this->resources_.insert({key, std::move(res)});
+    {
+        std::lock_guard<std::mutex> guard(this->mut_);
+        this->resources_.insert({key, std::move(res)});
+    }
 
     return key;
 }
@@ -43,7 +48,8 @@ size_t pixelarium::resources::ImageResourcePool::SetResource(unique_ptr<Pixelari
 /// @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(size_t id, std::unique_ptr<imaging::PixelariumImage> res)
+bool pixelarium::resources::ImageResourcePool::ModifyResource(ResourceKey id,
+                                                              std::unique_ptr<imaging::PixelariumImage> res)
 {
     auto search{this->resources_.find(id)};
     if (search == this->resources_.end()) return false;
@@ -56,7 +62,7 @@ bool pixelarium::resources::ImageResourcePool::ModifyResource(size_t id, std::un
 /// @brief Deletes a resource from the pool.
 /// @param id The ID of the resource to delete.
 /// @return True if the resource was deleted, false otherwise.
-bool pixelarium::resources::ImageResourcePool::DeleteResource(size_t id)
+bool pixelarium::resources::ImageResourcePool::DeleteResource(ResourceKey id)
 {
     auto search{this->resources_.find(id)};
     if (search == this->resources_.end()) return false;
@@ -70,10 +76,12 @@ bool pixelarium::resources::ImageResourcePool::DeleteResource(size_t 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(size_t, const imaging::PixelariumImage&)>& func)
+    const std::function<void(ResourceKey, size_t, const imaging::PixelariumImage&)>& func)
 {
+    size_t idx{0};
     for (const auto& e : this->resources_)
     {
-        func(e.first, *e.second);
+        func(e.first, idx, *e.second);
+        ++idx;
     }
 }

lib/resources/resource.hpp

@@ -3,6 +3,7 @@
 #include <concepts>
 #include <functional>
 #include <memory>
+#include <mutex>
 #include <optional>
 #include <unordered_map>
 
@@ -10,6 +11,7 @@
 
 namespace pixelarium::resources
 {
+    using ResourceKey = size_t;
 struct IResource
 {
     virtual ~IResource() = default;
@@ -24,10 +26,10 @@ class IResourcePool
    public:
     virtual ~IResourcePool() = default;
     virtual std::optional<const ResT*> GetResource(size_t id) const = 0;
-    virtual size_t SetResource(std::unique_ptr<ResT> res) = 0;
-    virtual bool ModifyResource(size_t id, std::unique_ptr<ResT> res) = 0;
-    virtual bool DeleteResource(size_t id) = 0;
-    virtual void EnumerateResources(const std::function<void(size_t, const ResT&)>& func) = 0;
+    virtual ResourceKey SetResource(std::unique_ptr<ResT> res) = 0;
+    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::PixelariumImage&)>& func) = 0;
     virtual size_t GetTotalSize() const = 0;
 };
 
@@ -46,20 +48,21 @@ class ImageResourcePool : public IResourcePool<imaging::PixelariumImage>
     ImageResourcePool& operator=(ImageResourcePool&) = delete;
     ImageResourcePool& operator=(ImageResourcePool&&) = delete;
 
-    std::optional<const imaging::PixelariumImage*> GetResource(size_t id) const override;
-    size_t SetResource(std::unique_ptr<imaging::PixelariumImage> res) override;
-    bool ModifyResource(size_t id, std::unique_ptr<imaging::PixelariumImage> res) override;
-    bool DeleteResource(size_t id) override;
+    std::optional<const imaging::PixelariumImage*> GetResource(ResourceKey id) const override;
+    ResourceKey SetResource(std::unique_ptr<imaging::PixelariumImage> res) override;
+    bool ModifyResource(ResourceKey id, std::unique_ptr<imaging::PixelariumImage> res) override;
+    bool DeleteResource(ResourceKey id) override;
 
-    void EnumerateResources(const std::function<void(size_t, const imaging::PixelariumImage&)>& func) override;
+    void EnumerateResources(const std::function<void(ResourceKey, size_t, const imaging::PixelariumImage&)>& func) override;
 
     template <typename Callable>
-    requires std::invocable<Callable, size_t, const imaging::PixelariumImage&>
+    requires std::invocable<Callable, ResourceKey, size_t, const imaging::PixelariumImage&>
     void Enumerate(Callable&& func) const
     {
+        size_t idx{0};
         for (const auto& e : this->resources_)
         {
-            func(e.first, *e.second);
+            func(e.first, idx, *e.second);
         }
     }
 
@@ -67,5 +70,6 @@ class ImageResourcePool : public IResourcePool<imaging::PixelariumImage>
 
    private:
     std::unordered_map<size_t, std::unique_ptr<imaging::PixelariumImage>> resources_;
+    std::mutex mut_;
 };
 }  // namespace pixelarium::resources

src/MyApp.cpp

@@ -1,13 +1,15 @@
 #include "MyApp.hpp"
 
+#include <cstddef>
 #include <format>
 #include <memory>
 
+#include "app_resources_default.h"
+#include "app_resources_local.h"
 #include "imaging/PixelariumImage.hpp"
 #include "imgui.h"
 #include "portable-file-dialogs.h"
-#include "app_resources_default.h"
-#include "app_resources_local.h"
+#include "rendering/RenderImageManager.hpp"
 #include "utilities/ILog.hpp"
 
 using namespace pixelarium::imaging;
@@ -35,17 +37,68 @@ void pixelarium::ui::MyApp::Run()
 {
     if (demop_) ImGui::ShowDemoWindow(&this->demop_);
     if (image_listp_) this->ImageGalleryRender();
+
+    this->RenderImages();
+}
+
+void pixelarium::ui::MyApp::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::MyApp::ImageGalleryRender()
 {
-    if (ImGui::BeginListBox("ListBox"))
+    ImGui::SetNextWindowSize(ImVec2(300, 500));
+    ImGui::Begin(SHOWIMAGEGALLERY);
+
+    // 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, const imaging::PixelariumImage&) -> void
-                                 { ImGui::Selectable(std::format("Image {}", id).c_str()); });
+        pool_.EnumerateResources(
+            [&](size_t id, size_t idx, const imaging::PixelariumImage& 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_);
+    }
+
+    ImGui::End();  // end gallery window
 }
 
 void pixelarium::ui::MyApp::LoadImageProt()
@@ -56,6 +109,6 @@ void pixelarium::ui::MyApp::LoadImageProt()
     {
         this->logger_.Debug(std::format("{}: Creating image {}", __FUNCTION__, p));
 
-        last_id = image_view_model_->AddImage(std::make_unique<PixelariumImage>(p));
+        pool_.SetResource(std::make_unique<PixelariumImage>(p));
     }
 }

src/MyApp.hpp

@@ -1,12 +1,13 @@
 #pragma once
 
+#include <cstddef>
 #include <memory>
 
 #include "AppGLFW.hpp"
 #include "imgui.h"
+#include "rendering/RenderImageManager.hpp"
 #include "resources/resource.hpp"
 #include "utilities/ILog.hpp"
-#include "viewmodels/ImageViewFactory.hpp"
 
 namespace pixelarium::ui
 {
@@ -14,9 +15,10 @@ class MyApp : public application::AppGLFW
 {
    public:
     MyApp(const utils::log::ILog& log, pixelarium::resources::ImageResourcePool& pool)
-        : application::AppGLFW(log), pool_(pool)
+        : application::AppGLFW(log),
+          pool_(pool),
+          render_manager_(std::make_unique<render::RenderImageManager>(pool, log))
     {
-        image_view_model_ = std::make_unique<ImageViewFactory>(pool_);
     }
 
    protected:
@@ -27,12 +29,15 @@ class MyApp : public application::AppGLFW
    private:
     void LoadImageProt();
     void ImageGalleryRender();
+    void RenderImages();
 
    private:
     resources::ImageResourcePool& pool_;
-    std::unique_ptr<ImageViewFactory> image_view_model_;
-    bool image_listp_{false};
+    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

src/app_resources_local.h.in

@@ -3,6 +3,10 @@
 // Currently, there is no need for this to be a configurable header.
 // It is left as such to keep the API open for possible build-system
 // injections in future.
+// clang-format off
+#define SHOWIMGUIDEMOS      "ImGui Demos"
+#define SHOWIMAGEGALLERY    "Image Gallery"
+#define AUTOSHOWSELECTED    "Auto View"
+#define OPENIMAGE           "Open"
 
-#define SHOWIMGUIDEMOS "ImGui Demos"
-#define SHOWIMAGEGALLERY "Image Gallery"
+// clang-format on

src/viewmodels/ImageViewFactory.cpp

@@ -1,15 +0,0 @@
-#include "ImageViewFactory.hpp"
-#include <memory>
-#include <optional>
-
-using namespace pixelarium::ui;
-
-std::unique_ptr<PixelariumImageView> ImageViewFactory::RenderImage(size_t image_id)
-{
-    auto img{this->image_pool_.GetResource(image_id)};
-
-    if (!img.has_value()) return nullptr;
-
-    // beware: here we copy the actual image resource over to the new image
-    return std::make_unique<PixelariumImageView>(std::make_shared<Image>(*img.value()));
-}

src/views/PixelariumImageView.cpp

@@ -1,53 +0,0 @@
-#include "PixelariumImageView.hpp"
-
-#include <format>
-
-#include "imgui.h"
-
-using namespace pixelarium::ui;
-
-static bool 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))
-    {
-        return true;
-    }
-
-    return false;
-}
-
-ImVec2 aspect_const_dimensions(const pixelarium::imaging::PixelariumImage& img, const ImVec2& curr_dim)
-{
-    const auto w_fact = (static_cast<float>(curr_dim.x) / img.GetImage().cols);
-    const auto h_fact = (static_cast<float>(curr_dim.y) / img.GetImage().rows);
-
-    const auto fact = w_fact < h_fact ? w_fact : h_fact;
-
-    return ImVec2(img.GetImage().cols * fact, img.GetImage().rows * fact);
-}
-
-void PixelariumImageView::ShowImage()
-{
-    if (this->open_p)
-    {
-        ImGui::Begin("An image", &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(this->img_->GetImage().cols, this->img_->GetImage().rows);
-
-        ImGui::Image(reinterpret_cast<ImTextureID>(reinterpret_cast<void*>(texture)),
-                     aspect_const_dimensions(*this->img_, new_dim));
-
-        ImGui::Separator();
-        ImGui::Text("%s", std::format("Dimensions W: {}, H: {}", curr_dim_.x, curr_dim_.y).c_str());
-
-        ImGui::End();
-    }
-}

tests/lib/resources/test_resource.cpp

@@ -82,7 +82,7 @@ TEST(ImageResourcePoolTest, EnumerateResources)
     auto id2 = pool.SetResource(std::make_unique<DummyImage>());
     std::vector<size_t> found_ids{};
 
-    pool.EnumerateResources([&found_ids](size_t id, const pixelarium::imaging::PixelariumImage&) { found_ids.push_back(id); });
+    pool.EnumerateResources([&found_ids](size_t id, size_t, const pixelarium::imaging::PixelariumImage&) { found_ids.push_back(id); });
 
     EXPECT_EQ(found_ids.size(), 2);
     EXPECT_NE(std::find(found_ids.begin(), found_ids.end(), id1), found_ids.end());
@@ -96,7 +96,7 @@ TEST(ImageResourcePoolTest, TemplatedEnumerate)
     auto id2 = pool.SetResource(std::make_unique<DummyImage>());
     std::vector<size_t> found_ids{};
 
-    pool.Enumerate([&found_ids](size_t id, const pixelarium::imaging::PixelariumImage&) { found_ids.push_back(id); });
+    pool.Enumerate([&found_ids](size_t id, size_t, const pixelarium::imaging::PixelariumImage&) { found_ids.push_back(id); });
 
     EXPECT_EQ(found_ids.size(), 2);
     EXPECT_NE(std::find(found_ids.begin(), found_ids.end(), id1), found_ids.end());