- Painting the canvas is done by overlaying the multiple layers.
- Drawing each overlay is implemented as polymorphism of OOP.
- Refine the Undo/Redo mechanism.
- Some adjustments.
CORE-17969
- Add DoCreate methods to CFullscreenWindow, CMiniatureWindow, and CMainWindow classes.
- Do encapsulation around mainWindow and _tWinMain.
- Add GetOpenFileName, GetSaveFileName, and ChooseColor helper methods to CMainWindow class.
- Move some code in WinMain into CMainWindow::OnCreate.
- Delay creation of CFullscreenWindow and CMiniatureWindow.
- Extend ATL CImage class as CImageDx in newly-created atlimagedx.h of mspaint.
CORE-18867
- Use Microsoft standard _countof macro instead of SIZEOF.
- Rename definitions.h as resource.h.
- Move some macro definitions to its proper place.
CORE-17931
- Check the denominator for zero for both zoomed width and height.
- Do not allow to move zoom slider above possible position.
- Move commonly used `zoomTo` function into new header file.
CORE-14539
