When minimizing a window, we get this sequence of events:
WM_WINDOWPOSCHANGING
WM_GETMINMAXINFO
WM_NCCALCSIZE
WM_WINDOWPOSCHANGED - IsIconic() is true
WM_MOVE
WM_SIZE - SDL sees minimized state here
When restoring a window, we get this sequence of events:
WM_WINDOWPOSCHANGING
WM_GETMINMAXINFO
WM_NCCALCSIZE
WM_NCPAINT
WM_ERASEBKGND
WM_WINDOWPOSCHANGED - IsIconic() is false
WM_MOVE
WM_SIZE - SDL sees restored state here
On Windows 10 a minimized window has a non-empty client rect, so we were delivering a minimized size before SDL knows that the window is minimized, and then ignoring the restored size when handling the restore message.
The fix is to use IsIconic() which returns the correct window state when WM_WINDOWPOSCHANGED is actually delivered.
Simple DirectMedia Layer is a cross-platform development library designed
to provide low level access to audio, keyboard, mouse, joystick, and graphics
hardware via OpenGL and Direct3D. It is used by video playback software,
emulators, and popular games including Valve's award winning catalog
and many Humble Bundle games.
More extensive documentation is available in the docs directory, starting
with README.md
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