From 307b0b78130252aa45d8951cf88b9b400c6eea9b Mon Sep 17 00:00:00 2001 From: "Ryan C. Gordon" Date: Tue, 2 Aug 2022 10:50:51 -0400 Subject: [PATCH] video: Add a warning to the docs about using SDL_GetDisplayDPI. Fixes #5647. --- include/SDL_video.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/include/SDL_video.h b/include/SDL_video.h index 0b139a057..9cf662c68 100644 --- a/include/SDL_video.h +++ b/include/SDL_video.h @@ -444,6 +444,15 @@ extern DECLSPEC int SDLCALL SDL_GetDisplayUsableBounds(int displayIndex, SDL_Rec * A failure of this function usually means that either no DPI information is * available or the `displayIndex` is out of range. * + * **WARNING**: This reports the DPI that the hardware reports, and it is not + * always reliable! It is almost always better to use SDL_GetWindowSize() to + * find the window size, which might be in logical points instead of pixels, + * and then SDL_GL_GetDrawableSize(), SDL_Vulkan_GetDrawableSize(), + * SDL_Metal_GetDrawableSize(), or SDL_GetRendererOutputSize(), and compare + * the two values to get an actual scaling value between the two. We will + * be rethinking how high-dpi details should be managed in SDL3 to make + * things more consistent, reliable, and clear. + * * \param displayIndex the index of the display from which DPI information * should be queried * \param ddpi a pointer filled in with the diagonal DPI of the display; may