SDL_GetDisplayContentScale - Man Page

#include <SDL3/SDL_video.h>

float SDL_GetDisplayContentScale(SDL_DisplayID displayID);

The content scale is the expected scale for content based on the DPI settings of the display. For example, a 4K display might have a 2.0 (200%) display scale, which means that the user expects UI elements to be twice as big on this display, to aid in readability.

After window creation, SDL_GetWindowDisplayScale() should be used to query the content scale factor for individual windows instead of querying the display for a window and calling this function, as the per-window content scale factor may differ from the base value of the display it is on, particularly on high-DPI and/or multi-monitor desktop configurations.

displayID

the instance ID of the display to query.

Returns the content scale of the display, or 0.0f on failure; call SDL_GetError() for more information.

This function should only be called on the main thread.

This function is available since SDL 3.2.0.

SDL_GetWindowDisplayScale(3), SDL_GetDisplays(3)