SDL_SetRenderLogicalPresentation

Set a device-independent resolution and presentation mode for rendering.

Header File

Syntax

bool SDL_SetRenderLogicalPresentation(SDL_Renderer *renderer, int w, int h, SDL_RendererLogicalPresentation mode);

Function Parameters

SDL_Renderer *	renderer	the rendering context.
int	w	the width of the logical resolution.
int	h	the height of the logical resolution.
SDL_RendererLogicalPresentation	mode	the presentation mode used.

Return Value

(bool) Returns true on success or false on failure; call SDL_GetError() for more information.

Remarks

This function sets the width and height of the logical rendering output. The renderer will act as if the current render target is always the requested dimensions, scaling to the actual resolution as necessary.

This can be useful for games that expect a fixed size, but would like to scale the output to whatever is available, regardless of how a user resizes a window, or if the display is high DPI.

Logical presentation can be used with both render target textures and the renderer's window; the state is unique to each render target, and this function sets the state for the current render target. It might be useful to draw to a texture that matches the window dimensions with logical presentation enabled, and then draw that texture across the entire window with logical presentation disabled. Be careful not to render both with logical presentation enabled, however, as this could produce double-letterboxing, etc.

You can disable logical coordinates by setting the mode to SDL_LOGICAL_PRESENTATION_DISABLED, and in that case you get the full pixel resolution of the render target; it is safe to toggle logical presentation during the rendering of a frame: perhaps most of the rendering is done to specific dimensions but to make fonts look sharp, the app turns off logical presentation while drawing text, for example.

For the renderer's window, letterboxing is drawn into the framebuffer if logical presentation is enabled during SDL_RenderPresent; be sure to reenable it before presenting if you were toggling it, otherwise the letterbox areas might have artifacts from previous frames (or artifacts from external overlays, etc). Letterboxing is never drawn into texture render targets; be sure to call SDL_RenderClear() before drawing into the texture so the letterboxing areas are cleared, if appropriate.

You can convert coordinates in an event into rendering coordinates using SDL_ConvertEventToRenderCoordinates().

Thread Safety

This function should only be called on the main thread.

Version

This function is available since SDL 3.2.0.