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/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_;
 }