Aaron Barany
I realized I made a minor mistake in my patch: I changed the constructor prototype for SDL_DisplayData, but didn't update the declaration in the .h file. The compiler and linker don't complain, but it would probably be best to fix in case a later change runs into a problem from the mismatch. I have attached a patch to fix this.
Aaron Barany
There appears to be no way to directly access the display DPI on iOS, so as an approximation the DPI for the iPhone 1 is used as a base value and is multiplied by the screen's scale. This should at least give a ballpark number for the various screen scales. (based on https://stackoverflow.com/questions/25756087/detecting-iphone-6-6-screen-sizes-in-point-values it appears that both 2x and 3x are used)
I have updated the patch to use a table of current devices and use a computation as a fallback. I have also updated the fallback computation to be more accurate.
Previously, SDL would always expose display modes and window dimensions in terms of pixels, and would add an extra 'fake' display mode on retina screens which would contain the non-retina resolution. Calling SDL_CreateWindow with the dimensions of that fake display mode would not work.
Now, SDL only exposes display modes and window dimensions in terms of points rather than pixels. If the SDL_WINDOW_ALLOW_HIGHDPI flag is passed into SDL_CreateWindow, then any OpenGL contexts created from that window will be sized in pixels rather than points (retrievable with SDL_GL_GetDrawableSize.) Window dimensions and mouse coordinates are still in terms of points rather than pixels even with that flag.
This matches the behavior of SDL in OS X more closely, and lets users choose whether to make use of retina displays and lets them handle it properly.
--HG--
branch : iOS-improvements
Alex Szpakowski
Now that SDL for iOS requires at least iOS 5.1 at runtime, there are several old codepaths in the UIKit backend which can be removed. I've attached a patch which does so.
