This is a Win32-specific fix for bug 2726. A WinRT fix for this bug was applied
separately, via https://hg.libsdl.org/SDL/rev/bea2e725e29a
This fix applies SDL_TOUCH_MOUSEID to 'mouse' events coming from touch devices,
but only when relative-mouse-mode is turned OFF. This bug is still present
when relative-mouse-mode is ON, however Microsoft does not provide documentation
on whether or not those input events (which come from WM_INPUT) can be
identified as touch-specific or not. Unofficially, that data might be available
(via GetMessageExtraInfo()), however this patch only uses MS-documented APIs.
Zack Middleton
Using X11 (on Debian Wheezy), SDL_GetModState() & KMOD_NUM and KMOD_CAPS are not set to system state (numlock/capslock LEDs). Pressing numlock or capslock toggles the mod state, though if num/caps lock is enabled before starting the program it's still reversed from system state. This makes getting KMOD_NUM and KMOD_CAPS in programs unreliable. This can be seen using the checkkeys test program.
The function that appears to have handle this in SDL 1.2 is X11_SetKeyboardState. The function call is commented out with "FIXME:" in SDL 2.
Using Windows backend through WINE; on first key press if numlock and/or capslock is enabled on system, numlock/capslock SDL_SendKeyboardKey is run and toggles KMOD_NUM/KMOD_CAPS to the correct state. On X11 this does not happen.
The attached patch makes X11 backend set keyboard state on window focus if no window was previously focused. It sets all keys to system up/down state and toggles KMOD_NUM/KMOD_CAPS via SDL_SendKeyboardKey to match system if needed. The patch is based on SDL 1.2's X11_SetKeyboardState.
Coriiander
Upon creating a window, a window property is added to it through the Win32-function "SetProp". This is done in the SDL-function "SetupWindowData" in file "src\video\windows\SDL_windowswindow.c".
Whenever you call "SetProp" to add a property to a Win32-window, you should also call the Win32-function "RemoveProp" to remove it before destroying that Win32-window.
While you might think that it's ok and that Windows will clean up nicely itself, it is not ok. It is against all Win32-API guidelines and is mostlikely a leak. Especially on external windows (CreateWindowFrom) you want to have things done right, not messy and leaky, affecting some other module. Even if SDL gets shutdown entirely that external window will now forever still have the "SDL_WindowData" prop attached to it.
The backing scale factor can change when the window moves between retina and non-retina displays.
The only other way to detect such a change is to compare the output of SDL_GL_GetDrawableSize or SDL_GetRendererOutputSize every frame, which is less than desirable, especially since the necessary app logic is likely already being executed when a window resize event is received.
This lets SDL-based apps respond to "Open With" commands properly, as they
can now obtain the requested path via a standard SDL dropfile event.
This is only checked on startup, so apps don't get drop events at any other
time, even if Android supports that, but this is still a definite
improvement.
Fixes Bugzilla #2762.
