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/app/rendering/PixelariumImageViewDefault.hpp

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <memory>
+
+#include "CvMatRender.hpp"
+#include "IPixelariumImageView.hpp"
+#include "imaging/IPixelariumImage.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;
+        // this->SetInitialSize();
+    }
+    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_{};
+    CvMatRender render_;
+
+   private:
+    void RefreshCachedImage();
+};
+}  // namespace pixelarium::application