cjj_009@yahoo.com 2009-12-14 20:32:35 PST

I've been working on an SDL/OpenGL program, that among other things, must deal
with resizing events in order to adjust the aspect ratio.
It doesn't always seem to get the SDL_VIDEORESIZE event when it should, causing
the aspect ratio to not be adjusted as needed.

I've run it in debug mode and made these observations:
*When it initially starts up, if I maximize the window, it receives the
SDL_VIDEORESIZE event as needed.
*If, after starting up the the application and maximizing the window, I then
restore the window by double clicking the title bar, it does NOT receive the
SDL_VIDEORESIZE event.
*I can repeat the last two steps, and it will get continue to get the
SDL_VIDEORESIZE on the maximize but not get one on the restore.
*If I then do a slight adjustment to the width or height of the window, it will
get the SDL_VIDEORESIZE event.
*From then on, if I do restore operations to the window, the SDL_VIDEORESIZE
event will be caught properly.

See http://forums.libsdl.org/viewtopic.php?t=5291 for additional information.

vgvgf 2010-03-28 15:15:16 PDT
Proposed patch for SDL_resize.c

The width and height values stored in SDL_VideoSurface are the sizes of the
video surface when it was created. So, when the window is rezised back to its
creation size, the following condition will make the SDL_PrivateResize function
stop, and the video resize msg won't be queued.
if ( ! SDL_VideoSurface ||
     ((w == SDL_VideoSurface->w) && (h == SDL_VideoSurface->h)) ) {
    return(0);
}

Sam Lantinga 2011-12-30 02:59:51 PST
I'm okay with applying this patch, but be aware that the expected response to a
resize message is that you call SDL_SetVideoMode() again with the new mode.
This signals SDL that you're expecting the new size, and there may be other
problems if you don't do this.