Misc (#19)

* get image returns optional<Mat> instead of unique_ptr<Mat>

* introduce complexity

* rename image load function

* add example for a basic reader for binary image files

* fix windows build?

* add a status bar underneath the menu bar

* use status bar in custom_0 example app

* clang formats

* packing w/ pragma push

* add "Save As" functions to image views

* resize over reserve

* rm local override uri

* add simple thread pool

* rename to simple_thread_pool

* get rid of useless renderlib

* document version inc

* extract hardcoded values to in-header

* clang format patch

* clone registered image in custom_0

* document binary-file header

* minor fixes

* clang format

* rm unused render cmake

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 "utilities/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.
@@ -193,6 +243,18 @@ 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.
@@ -213,3 +275,14 @@ void pixelarium::application::AppGLFW::LogLevelSelect()
         ImGui::EndCombo();
     }
 }
+
+void pixelarium::application::AppGLFW::SetStatusTimed(const std::string& status, size_t seconds)
+{
+    SetStatus(status);
+    utils::simple_thread_pool::run_asynch(
+        [this, seconds]()
+        {
+            std::this_thread::sleep_for(std::chrono::seconds(seconds));
+            ResetStatus();
+        });
+}

lib/app/AppGLFW.hpp

@@ -2,9 +2,8 @@
 
 #include <GLFW/glfw3.h>
 
-#include <memory>
+#include <format>
 
-#include "imgui.h"
 #include "utilities/ILog.hpp"
 
 namespace pixelarium::application
@@ -19,6 +18,21 @@ class AppGLFW
     /// @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() {}
@@ -47,5 +61,7 @@ class AppGLFW
     void LogLevelSelect();
     int log_level_{0};
     GLFWwindow* window = nullptr;
+    bool show_status_{false};
+    std::string status_message_{};
 };
 }  // namespace pixelarium::application

lib/app/CMakeLists.txt

@@ -16,15 +16,30 @@ set(APPLIBSRC
   ${imgui_DIR}/backends/imgui_impl_opengl3.cpp
   ${imgui_DIR}/backends/imgui_impl_glfw.cpp)
 
+set(RENDERSRC
+  rendering/RenderHelpers.hpp
+  rendering/RenderHelpers.cpp
+  rendering/CvMatRender.hpp
+  rendering/CvMatRender.cpp
+  rendering/RenderImageManager.hpp
+  rendering/RenderImageManager.cpp
+  rendering/IPixelariumImageView.hpp
+  rendering/IPixelariumImageView.cpp
+  rendering/PixelariumImageViewDefault.hpp
+  rendering/PixelariumImageViewDefault.cpp
+  rendering/PixelariumImageViewCzi.hpp
+  rendering/PixelariumImageViewCzi.cpp
+  rendering/ImageViewFactory.hpp
+  rendering/ImageViewFactory.cpp)
+
 set(APPLIBNAME pixelariumapplicationlib)
 
 add_library(${APPLIBNAME}
-  STATIC ${APPLIBSRC})
+  STATIC ${APPLIBSRC} ${RENDERSRC})
 
 target_link_libraries(${APPLIBNAME}
   PRIVATE pixelariumutilslib
-  PRIVATE pixelariumimagelib
-  PRIVATE pixelariumrenderlib)
+  PRIVATE pixelariumimagelib)
 
 # This needs to be public to let the consumer know about it.
 if(WIN32)
@@ -47,6 +62,7 @@ target_include_directories(${APPLIBNAME}
   PRIVATE ${CMAKE_BINARY_DIR}
   PRIVATE ${PROJECT_SOURCE_DIR}/lib
   PRIVATE ${PROJECT_SOURCE_DIR}/lib/imaging
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/rendering
   PUBLIC ${pfd_DIR}
   PUBLIC ${imgui_DIR}
   PUBLIC ${imgui_DIR}/backends)

lib/app/DefaultApp.cpp

@@ -25,7 +25,7 @@ void DefaultApp::MenuBarOptionsColumn2()
     {
         if (ImGui::MenuItem(LOADIMAGE))
         {
-            this->LoadImage();
+            this->LoadImageDialogue();
         }
 
         ImGui::EndMenu();
@@ -40,7 +40,7 @@ void DefaultApp::Run()
     this->gallery_.RenderImages();
 }
 
-void 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)

lib/app/DefaultApp.hpp

@@ -19,7 +19,7 @@ class DefaultApp : public AppGLFW
     DefaultApp(const utils::log::ILog& log, pixelarium::resources::ImageResourcePool& pool)
         : application::AppGLFW(log), pool_(pool), gallery_(log, pool)
     {
-        gallery_.SetLoadFunction([&]() -> void { this->LoadImage(); });
+        gallery_.SetLoadFunction([&]() -> void { this->LoadImageDialogue(); });
     }
 
    protected:
@@ -32,7 +32,7 @@ class DefaultApp : public AppGLFW
     application::PixelariumImageGallery gallery_;
 
    protected:
-    void LoadImage();
+    void LoadImageDialogue();
 
    private:
     bool image_listp_{true};

lib/app/PixelariumGallery.cpp

@@ -23,7 +23,7 @@ void PixelariumImageGallery::RenderGallery()
     if (ImGui::BeginListBox("Image List", ImVec2(200, 400)))
     {
         pool_.EnumerateResources(
-            [&](size_t id, size_t idx, const imaging::IPixelariumImage& img) -> void
+            [&](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))
@@ -74,7 +74,7 @@ void PixelariumImageGallery::RenderGallery()
 void PixelariumImageGallery::RenderImages()
 {
     this->render_manager_->Enumerate(
-        [&](resources::ResourceKey key, render::RenderImageStateWrapper& render_state)
+        [&](resources::ResourceKey key, application::RenderImageStateWrapper& render_state)
         {
             render_state.view->ShowImage();
 

lib/app/PixelariumGallery.hpp

@@ -3,13 +3,14 @@
 #include "rendering/RenderImageManager.hpp"
 #include "resources/resource.hpp"
 #include "utilities/ILog.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>
-concept GalleryT = requires(P& p) { static_cast<resources::IResourcePool<P>&>(p); };
+template <typename P, class D>
+concept GalleryT = requires(P& p) { static_cast<resources::IResourcePool<P, D>&>(p); };
 
 /// @brief Interface for a Pixelarium gallery.
 ///
@@ -33,7 +34,7 @@ class PixelariumImageGallery : IPixelariumGallery<resources::ImageResourcePool>
 
    public:
     PixelariumImageGallery(const Log& log, resources::ImageResourcePool& pool)
-        : pool_{pool}, log_{log}, render_manager_(std::make_unique<render::RenderImageManager>(pool, log))
+        : pool_{pool}, log_{log}, render_manager_(std::make_unique<application::RenderImageManager>(pool, log))
     {
     }
 
@@ -49,7 +50,7 @@ class PixelariumImageGallery : IPixelariumGallery<resources::ImageResourcePool>
     std::function<void()> load_image_{};
     Pool& pool_;
     const Log& log_;
-    std::unique_ptr<render::RenderImageManager> render_manager_;
+    std::unique_ptr<application::RenderImageManager> render_manager_;
     bool image_listp_{true};
     bool auto_show_selectd_image_{true};
     size_t selected_image_{0};

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/rendering/CvMatRender.cpp

@@ -9,7 +9,7 @@ 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(const cv::Mat& 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
@@ -20,7 +20,7 @@ pixelarium::render::CvMatRender::CvMatRender(const cv::Mat& img) : base_(img), t
 
 /// @brief Destructor for the CvMatRender class.
 /// Deallocates the OpenGL texture if it exists.
-pixelarium::render::CvMatRender::~CvMatRender()
+pixelarium::application::CvMatRender::~CvMatRender()
 {
     if (texture_)
     {
@@ -32,7 +32,7 @@ pixelarium::render::CvMatRender::~CvMatRender()
 /// @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())
     {
@@ -89,12 +89,12 @@ 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)
 {
     cv::resize(this->base_, this->img_, cv::Size(0, 0), factor, factor, cv::INTER_LINEAR_EXACT);
 
@@ -105,7 +105,7 @@ 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)
 {
     const auto sz{this->base_.size()};
 
@@ -116,7 +116,7 @@ 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()
 {
     // we copy here
     this->img_ = this->base_.clone();

lib/app/rendering/CvMatRender.hpp

@@ -15,7 +15,7 @@
 #include <opencv2/core/mat.hpp>
 // clang-format on
 
-namespace pixelarium::render
+namespace pixelarium::application
 {
 /// @brief Renders cv::Mat bitmaps as OpenGL textures.
 class CvMatRender
@@ -49,4 +49,4 @@ class CvMatRender
     GLuint uploadTexture();
 };
 
-}  // namespace pixelarium::render
+}  // namespace pixelarium::application

lib/app/rendering/IPixelariumImageView.cpp

@@ -0,0 +1,26 @@
+#include "IPixelariumImageView.hpp"
+
+#include <opencv2/imgcodecs.hpp>
+
+#include "app_resources_default.h"
+#include "portable-file-dialogs.h"
+
+auto pixelarium::application::IPixelariumImageView::ImageViewMenuBar() -> void
+{
+    if (ImGui::BeginMenuBar())
+    {
+        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_);
+            }
+        }
+
+        ImGui::EndMenuBar();
+    }
+}

lib/app/rendering/IPixelariumImageView.hpp

@@ -5,7 +5,7 @@
 #include "imaging/IPixelariumImage.hpp"
 #include "imgui.h"
 
-namespace pixelarium::render
+namespace pixelarium::application
 {
 /// @brief An interface defining the contract on views to dedicated implementations of IPixelariumImage
 class IPixelariumImageView
@@ -18,15 +18,23 @@ class IPixelariumImageView
    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:
-    std::shared_ptr<imaging::IPixelariumImage> img_{};
-    std::unique_ptr<cv::Mat> cached_image_{};
+    virtual void ImageViewMenuBar();
+
+   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::render
+}  // namespace pixelarium::application

lib/app/rendering/ImageViewFactory.cpp

@@ -3,17 +3,17 @@
 #include <format>
 #include <memory>
 
+#include "IPixelariumImageView.hpp"
+#include "PixelariumImageViewCzi.hpp"
+#include "PixelariumImageViewDefault.hpp"
 #include "imaging/IPixelariumImage.hpp"
 #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(
+std::unique_ptr<pixelarium::application::IPixelariumImageView> pixelarium::application::ImageViewFactory::RenderImage(
     resources::ResourceKey image_id)
 {
     using ImageType = imaging::ImageFileType;

lib/app/rendering/ImageViewFactory.hpp

@@ -1,15 +1,15 @@
 #pragma once
 
-#include "PixelariumImageViewDefault.hpp"
-#include "rendering/IPixelariumImageView.hpp"
+#include "IPixelariumImageView.hpp"
 #include "resources/resource.hpp"
 #include "utilities/ILog.hpp"
-namespace pixelarium::render
+
+namespace pixelarium::application
 {
 /// @brief Factory for instantiating matching views to different implementations of IPixelariumImage.
 class ImageViewFactory
 {
-    using Image = imaging::IPixelariumImage;
+    using Image = imaging::IPixelariumImageCvMat;
     using Pool = resources::ImageResourcePool;
     using Log = utils::log::ILog;
 
@@ -22,4 +22,4 @@ class ImageViewFactory
     Pool& image_pool_;
     const Log& log_;
 };
-}  // namespace pixelarium::render
+}  // namespace pixelarium::application

lib/app/rendering/PixelariumImageViewCzi.cpp

@@ -3,13 +3,29 @@
 #include <format>
 #include <memory>
 
+#include "CvMatRender.hpp"
 #include "RenderHelpers.hpp"
 #include "imaging/IPixelariumImage.hpp"
 #include "imaging/impl/PixelariumCzi.hpp"
 #include "imgui.h"
-#include "rendering/CvMatRender.hpp"
 
-pixelarium::render::PixelariumImageViewCzi::PixelariumImageViewCzi(std::shared_ptr<Image> img, const Log& log)
+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), render_(std::make_unique<CvMatRender>(*img->TryGetImage()))
 {
     img_ = img;
@@ -23,7 +39,7 @@ pixelarium::render::PixelariumImageViewCzi::PixelariumImageViewCzi(std::shared_p
             return true;
         });
 
-    this->SetInitialSize();
+    // this->SetInitialSize();
     log_.Info(std::format("{}: dimension map size: {}", __PRETTY_FUNCTION__, dimension_map_.size()));
 }
 
@@ -32,35 +48,36 @@ pixelarium::render::PixelariumImageViewCzi::PixelariumImageViewCzi(std::shared_p
 /// 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()
+void pixelarium::application::PixelariumImageViewCzi::ShowImage()
 {
     auto czi_img = std::static_pointer_cast<imaging::PixelariumCzi>(this->img_);
 
     if (!czi_img) return;
 
-    if (!this->cached_image_ || 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);
-        // 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;
-    }
+    RefreshCachedImage();
 
-    if (czi_img->Empty() || this->img_->type_ == imaging::ImageFileType::kUnknown || !cached_image_ ||
+    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 =
@@ -70,7 +87,7 @@ void pixelarium::render::PixelariumImageViewCzi::ShowImage()
 
     this->curr_dim_ = new_dim;
 
-    ImVec2 dim(cached_image_->cols, cached_image_->rows);
+    ImVec2 dim(cached_image_.cols, cached_image_.rows);
 
     ImGui::Image(reinterpret_cast<ImTextureID>(reinterpret_cast<void*>(texture)),
                  aspect_const_dimensions(dim, new_dim));

lib/app/rendering/PixelariumImageViewCzi.hpp

@@ -3,19 +3,19 @@
 #include <memory>
 #include <unordered_map>
 
+#include "CvMatRender.hpp"
+#include "IPixelariumImageView.hpp"
+#include "imaging/IPixelariumImage.hpp"
 #include "imgui.h"
 #include "libCZI_DimCoordinate.h"
-#include "rendering/CvMatRender.hpp"
-#include "rendering/IPixelariumImageView.hpp"
 #include "utilities/ILog.hpp"
 
-namespace pixelarium::render
+namespace pixelarium::application
 {
 /// @brief A CZI-specific implementation of IPixelariumImageView.
 class PixelariumImageViewCzi : public IPixelariumImageView
 {
-    using Image = imaging::IPixelariumImage;
-    using Render = render::CvMatRender;
+    using Image = imaging::IPixelariumImageCvMat;
     using Log = utils::log::ILog;
 
    public:
@@ -34,5 +34,8 @@ class PixelariumImageViewCzi : public IPixelariumImageView
     const Log& log_;
     std::unordered_map<libCZI::DimensionIndex, int> dimension_map_;
     std::unique_ptr<CvMatRender> render_;
+
+   private:
+    void RefreshCachedImage();
 };
-}  // namespace pixelarium::render
+}  // namespace pixelarium::application

lib/app/rendering/PixelariumImageViewDefault.cpp

@@ -3,31 +3,50 @@
 #include <format>
 
 #include "RenderHelpers.hpp"
+#include "app_resources_default.h"
 #include "imaging/IPixelariumImage.hpp"
 #include "imgui.h"
+
+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;
+    }
+}
+
 /// @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()
+void pixelarium::application::PixelariumImageViewDefault::ShowImage()
 {
-    if (!this->cached_image_ || this->is_dirty_)
-    {
-        this->cached_image_ = this->img_->TryGetImage();
-        this->is_dirty_ = false;
-    }
+    RefreshCachedImage();
 
-    if (this->img_->Empty() || this->img_->type_ == imaging::ImageFileType::kUnknown || !cached_image_ ||
+    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));
+    }
+
     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 =
@@ -37,7 +56,7 @@ void pixelarium::render::PixelariumImageViewDefault::ShowImage()
 
     this->curr_dim_ = new_dim;
 
-    ImVec2 dim(cached_image_->cols, cached_image_->rows);
+    ImVec2 dim(cached_image_.cols, cached_image_.rows);
 
     ImGui::Image(reinterpret_cast<ImTextureID>(reinterpret_cast<void*>(texture)),
                  aspect_const_dimensions(dim, new_dim));

lib/app/rendering/PixelariumImageViewDefault.hpp

@@ -2,25 +2,24 @@
 
 #include <memory>
 
+#include "CvMatRender.hpp"
+#include "IPixelariumImageView.hpp"
 #include "imaging/IPixelariumImage.hpp"
 #include "imgui.h"
-#include "rendering/CvMatRender.hpp"
-#include "rendering/IPixelariumImageView.hpp"
 
-namespace pixelarium::render
+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::IPixelariumImage;
-    using Render = render::CvMatRender;
+    using Image = imaging::IPixelariumImageCvMat;
 
    public:
     explicit PixelariumImageViewDefault(std::shared_ptr<Image> img) : render_(*img->TryGetImage())
     {
         img_ = img;
-        this->SetInitialSize();
+        // this->SetInitialSize();
     }
     PixelariumImageViewDefault() = delete;
     PixelariumImageViewDefault(PixelariumImageViewDefault&) = delete;
@@ -34,5 +33,8 @@ class PixelariumImageViewDefault : public IPixelariumImageView
    private:
     ImVec2 curr_dim_{};
     CvMatRender render_;
+
+   private:
+    void RefreshCachedImage();
 };
-}  // namespace pixelarium::render
+}  // namespace pixelarium::application

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/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/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));
@@ -44,7 +44,7 @@ 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
@@ -77,4 +77,4 @@ 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/RenderImageManager.hpp

@@ -4,14 +4,14 @@
 #include <unordered_map>
 #include <unordered_set>
 
+#include "IPixelariumImageView.hpp"
 #include "ImageViewFactory.hpp"
-#include "rendering/IPixelariumImageView.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
+namespace pixelarium::application
 {
 /// @brief Instead of directly using the view, we
 /// proxy it through a wrapper. This allows for arbitrary additional data
@@ -71,4 +71,4 @@ class RenderImageManager
 
     const utils::log::ILog& log_;
 };
-}  // namespace pixelarium::render
+}  // namespace pixelarium::application

lib/imaging/CMakeLists.txt

@@ -7,6 +7,7 @@ message(STATUS "OpenCV_LIBs from: " ${OpenCV_LIBS})
 
 set(IMAGELIBSRC
   IPixelariumImage.hpp
+  IPixelariumImage.cpp
   PixelariumImageFactory.hpp
   PixelariumImageFactory.cpp
   impl/PixelariumJpg.hpp

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

@@ -2,7 +2,6 @@
 
 #include <filesystem>
 #include <functional>
-#include <memory>
 #include <opencv2/core/mat.hpp>
 #include <string>
 
@@ -38,6 +37,7 @@ struct IImageQuery
 
 /// @brief This aims to be a generic image abstraction
 /// meant for codec specific implementation.
+template <class Data>
 class IPixelariumImage
 {
    public:
@@ -47,19 +47,19 @@ class IPixelariumImage
     /// @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;
+    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::unique_ptr<cv::Mat> TryGetImage(const IImageQuery& query) = 0;
+    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::unique_ptr<cv::Mat>> TryGetImages(const IImageQuery& query) = 0;
+    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.
@@ -92,4 +92,60 @@ class IPixelariumImage
    protected:
     std::filesystem::path uri_;
 };
+
+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/PixelariumImageFactory.cpp

@@ -3,13 +3,14 @@
 #include <cctype>
 #include <memory>
 
+#include "imaging/IPixelariumImage.hpp"
 #include "imaging/impl/PixelariumMem.hpp"
 #include "impl/PixelariumCzi.hpp"
 #include "impl/PixelariumJpg.hpp"
 #include "impl/PixelariumPng.hpp"
 #include "impl/PixelariumTiff.hpp"
 
-/*static*/ std::unique_ptr<pixelarium::imaging::IPixelariumImage>
+/*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)};

lib/imaging/PixelariumImageFactory.hpp

@@ -37,6 +37,6 @@ class PixelariumImageFactory
     using Log = utils::log::ILog;
 
    public:
-    static std::unique_ptr<IPixelariumImage> CreateImage(const std::string& uri, const Log& log);
+    static std::unique_ptr<IPixelariumImageCvMat> CreateImage(const std::string& uri, const Log& log);
 };
 }  // namespace pixelarium::imaging

lib/imaging/impl/PixelariumCzi.cpp

@@ -4,6 +4,8 @@
 #include <filesystem>
 #include <format>
 #include <memory>
+#include <opencv2/imgcodecs.hpp>
+#include <optional>
 #include <stdexcept>
 #include <utility>
 
@@ -48,8 +50,8 @@ constexpr int try_get_index_match(const pixelarium::imaging::CziParams& params,
     return index;
 }
 
-std::unique_ptr<cv::Mat> CZISubBlockToCvMat(std::shared_ptr<libCZI::IBitmapData> bitmap, libCZI::PixelType pixeltype,
-                                            const pixelarium::utils::log::ILog& log)
+std::optional<cv::Mat> CZISubBlockToCvMat(std::shared_ptr<libCZI::IBitmapData> bitmap, libCZI::PixelType pixeltype,
+                                          const pixelarium::utils::log::ILog& log)
 {
     size_t pixel_size{0};
     int target_type;
@@ -94,21 +96,21 @@ std::unique_ptr<cv::Mat> CZISubBlockToCvMat(std::shared_ptr<libCZI::IBitmapData>
             break;
     }
 
-    if (pixel_size < 0) return nullptr;
+    if (pixel_size < 0) return std::nullopt;
 
     log.Info(std::format("{}: source pixel type {}, target cv pixel type {}, pixel size {}", __PRETTY_FUNCTION__,
                          pixel_pair.first, pixel_pair.second, pixel_size));
 
     size_t height{bitmap->GetHeight()};
     size_t width{bitmap->GetWidth()};
-    auto fill_mat = std::make_unique<cv::Mat>(height, width, target_type);
+    auto fill_mat = 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);
+        unsigned char* target_row = fill_mat.ptr(h);
 
         for (size_t w{0}; w < width; ++w)
         {
@@ -139,7 +141,7 @@ std::unique_ptr<cv::Mat> CZISubBlockToCvMat(std::shared_ptr<libCZI::IBitmapData>
     return fill_mat;
 }
 
-std::unique_ptr<cv::Mat> pixelarium::imaging::PixelariumCzi::SubblockToCvMat(int index)
+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);
@@ -170,9 +172,9 @@ pixelarium::imaging::PixelariumCzi::PixelariumCzi(const std::string& uri, const
         });
 }
 
-std::unique_ptr<cv::Mat> pixelarium::imaging::PixelariumCzi::TryGetImage() { return SubblockToCvMat(0); }
+std::optional<cv::Mat> pixelarium::imaging::PixelariumCzi::TryGetImage() { return SubblockToCvMat(0); }
 
-std::unique_ptr<cv::Mat> pixelarium::imaging::PixelariumCzi::TryGetImage(const IImageQuery& query)
+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_);

lib/imaging/impl/PixelariumCzi.hpp

@@ -18,7 +18,7 @@ struct CziParams : public IImageQuery
 };
 
 /// @brief Implements support for .czi-images in the realm of IPixelariumImage
-class PixelariumCzi : public IPixelariumImage
+class PixelariumCzi : public IPixelariumImageCvMat
 {
     using Log = pixelarium::utils::log::ILog;
 
@@ -31,16 +31,17 @@ class PixelariumCzi : public IPixelariumImage
 
     // 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;
 
-    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 implemented.");
     }
 
+   public:
     bool Empty() const noexcept override { return this->is_empty_; }
 
     const libCZI::SubBlockStatistics& GetStatistics() const { return this->image_statistics_; }
@@ -49,7 +50,7 @@ class PixelariumCzi : public IPixelariumImage
     const static ImageFileType type_{ImageFileType::kCzi};
 
    private:
-    std::unique_ptr<cv::Mat> SubblockToCvMat(int index);
+    std::optional<cv::Mat> SubblockToCvMat(int index);
 
    private:
     // this should be set by each image getter

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/PixelariumJpg.hpp

@@ -8,27 +8,28 @@
 namespace pixelarium::imaging
 {
 /// @brief Implements support for .jpg-images in the realm of IPixelariumImage
-class PixelariumJpg : public 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:

lib/imaging/impl/PixelariumMem.cpp

@@ -12,7 +12,7 @@ pixelarium::imaging::PixelariumMem::PixelariumMem(const cv::Mat& img, const std:
     this->uri_ = std::filesystem::path();
 }
 
-std::unique_ptr<cv::Mat> pixelarium::imaging::PixelariumMem::TryGetImage()
+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
@@ -22,5 +22,5 @@ std::unique_ptr<cv::Mat> pixelarium::imaging::PixelariumMem::TryGetImage()
     // 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 std::make_unique<cv::Mat>(this->img_);
+    return this->img_;
 }

lib/imaging/impl/PixelariumMem.hpp

@@ -9,7 +9,7 @@
 namespace pixelarium::imaging
 {
 /// @brief Implements support for in-memory images in the realm of IPixelariumImage
-class PixelariumMem : public IPixelariumImage
+class PixelariumMem : public IPixelariumImageCvMat
 {
     using Log = pixelarium::utils::log::ILog;
 
@@ -18,11 +18,11 @@ class PixelariumMem : public IPixelariumImage
 
     // 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 { throw std::runtime_error("Not implemented."); }
+    std::optional<cv::Mat> TryGetImage(const IImageQuery&) override { throw std::runtime_error("Not implemented."); }
 
-    std::vector<std::unique_ptr<cv::Mat>> TryGetImages(const IImageQuery&) override
+    std::vector<std::optional<cv::Mat>> TryGetImages(const IImageQuery&) override
     {
         throw std::runtime_error("Not implemented.");
     }

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/PixelariumPng.hpp

@@ -8,22 +8,22 @@
 namespace pixelarium::imaging
 {
 /// @brief Implements support for .png-images in the realm of IPixelariumImage
-class PixelariumPng : public 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.");

lib/imaging/impl/PixelariumTiff.cpp

@@ -16,11 +16,11 @@ pixelarium::imaging::PixelariumTiff::PixelariumTiff(const std::string& uri, cons
     this->uri_ = std::filesystem::path(uri);
 }
 
-std::unique_ptr<cv::Mat> pixelarium::imaging::PixelariumTiff::TryGetImage()
+std::optional<cv::Mat> pixelarium::imaging::PixelariumTiff::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.hpp

@@ -9,7 +9,7 @@
 namespace pixelarium::imaging
 {
 /// @brief Implements support for .tiff-images in the realm of IPixelariumImage
-class PixelariumTiff : public IPixelariumImage
+class PixelariumTiff : public IPixelariumImageCvMat
 {
     using Log = pixelarium::utils::log::ILog;
 
@@ -18,15 +18,15 @@ class PixelariumTiff : public IPixelariumImage
 
     // 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 tiff.");
     }
 
-    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 tiff.");

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/resources/resource.cpp

@@ -5,7 +5,9 @@
 #include <functional>
 #include <mutex>
 
-using pixelarium::imaging::IPixelariumImage;
+#include "imaging/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/resources/resource.hpp

@@ -38,7 +38,7 @@ concept ResT = requires(R& r) { static_cast<IResource&>(r); };
 
 /// @brief Defines an interface for a resource pool
 /// @tparam ResT  defines the resource type that is accepted by the pool
-template <typename ResT>
+template <typename ResT, class Data>
 class IResourcePool
 {
    public:
@@ -48,7 +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;
 };
@@ -58,7 +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;
@@ -68,17 +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};
@@ -91,7 +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/utilities/CMakeLists.txt

@@ -3,7 +3,9 @@ set(UTILSLIBNAME pixelariumutilslib)
 set(UTILSLIBSRC
   ILog.hpp
   SpdLogger.hpp
-  SpdLogger.cpp)
+  SpdLogger.cpp
+  simple_thread_pool.hpp
+  simple_thread_pool.cpp)
 
 add_library(${UTILSLIBNAME} STATIC ${UTILSLIBSRC})
 

lib/utilities/simple_thread_pool.cpp

@@ -0,0 +1,47 @@
+#include "simple_thread_pool.hpp"
+
+#include <functional>
+#include <mutex>
+
+using namespace pixelarium::utils;
+
+simple_thread_pool::simple_thread_pool(size_t num_threads)
+{
+    for (size_t i{0}; i < num_threads; ++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();
+                    }
+
+                    job();
+                }
+            });
+    }
+}
+
+simple_thread_pool::~simple_thread_pool()
+{
+    {
+        std::unique_lock<std::mutex> lck(thread_mutex_);
+        shutdown_ = true;
+    }
+
+    cv_.notify_all();
+    for (auto& th : workers_)
+    {
+        th.join();
+    }
+}

lib/utilities/simple_thread_pool.hpp

@@ -0,0 +1,56 @@
+#pragma once
+
+#include <condition_variable>
+#include <functional>
+#include <mutex>
+#include <queue>
+#include <thread>
+#include <vector>
+
+namespace pixelarium::utils
+{
+class simple_thread_pool
+{
+   public:
+    explicit simple_thread_pool(size_t);
+    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();
+
+    template <typename Callable>
+        requires std::invocable<Callable>
+    static auto run_asynch(Callable&& fun) -> void
+    {
+        simple_thread_pool::Global().enqueue(std::forward<Callable>(fun));
+    }
+
+   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();
+    }
+
+   private:
+    static auto Global() -> simple_thread_pool&
+    {
+        const auto kThreadCount{std::thread::hardware_concurrency() * 2};
+        static simple_thread_pool global_instance(kThreadCount == 0 ? 5 : kThreadCount);
+        return global_instance;
+    }
+    std::vector<std::thread> workers_;
+    std::condition_variable cv_;
+    std::mutex thread_mutex_;
+    std::queue<std::function<void()>> task_queue_;
+    bool shutdown_{false};
+};
+}  // namespace pixelarium::utils