We have gotten feedback that abstracting the coordinate system based on the display scale is unexpected and it is difficult to adapt existing applications to the proposed API.
The new approach is to provide the coordinate systems that people expect, but provide additional information that will help applications properly handle high DPI situations.
The concepts needed for high DPI support are documented in README-highdpi.md. An example of automatically adapting the content to display scale changes can be found in SDL_test_common.c, where auto_scale_content is checked.
Also, the SDL_WINDOW_ALLOW_HIGHDPI window flag has been replaced by the SDL_HINT_VIDEO_ENABLE_HIGH_PIXEL_DENSITY hint.
Fixes https://github.com/libsdl-org/SDL/issues/7709
It turns out that screen coordinates were confusing people, thinking that meant pixels, when instead they are virtual coordinates; device independent units defined as pixels scaled by the display scale. We'll use the term "points" for this going forward, to reduce confusion.
- SDL_AudioCVT is gone, even internally.
- libsamplerate is gone (I suspect our resampler is finally Good Enough).
- Cleanups and improvements to audio conversion interfaces.
- SDL_AudioStream can change its input/output format/rate/channels on the fly!
It turns out there's a race condition on X11 where the window could be placed by the window manager while being placed by the application, so we need to have the initial position available at window creation.
This function wasn't consistently correct across platforms and devices.
If you want the UI scale factor, you can use display_scale in the structure returned by SDL_GetDesktopDisplayMode(). If you need an approximate DPI, you can multiply this value times 160 on iPhone and Android, and 96 on other platforms.
This makes it clear what the new versions are, and in the case of SDL_RenderDrawPoint() and SDL_RenderDrawLine(), the coccinelle script actually does the (float) casts for you.
This fixes rounding errors with coordinate scaling and gives more flexibility in the presentation, as well as making it easy to maintain device independent resolution as windows move between different pixel density displays.
By default when a renderer is created, it will match the window size so window coordinates and render coordinates are 1-1.
Mouse and touch events are no longer filtered to change their coordinates, instead you can call SDL_ConvertEventToRenderCoordinates() to explicitly map event coordinates into the rendering viewport.
SDL_RenderWindowToLogical() and SDL_RenderLogicalToWindow() have been renamed SDL_RenderCoordinatesFromWindow() and SDL_RenderCoordinatesToWindow() and take floating point coordinates in both directions.
The viewport, clipping state, and scale for render targets are now persistent and will remain set whenever they are active.
Rather than iterating over display modes using an index, there is a new function SDL_GetFullscreenDisplayModes() to get the list of available fullscreen modes on a display.
{
SDL_DisplayID display = SDL_GetPrimaryDisplay();
int num_modes = 0;
SDL_DisplayMode **modes = SDL_GetFullscreenDisplayModes(display, &num_modes);
if (modes) {
for (i = 0; i < num_modes; ++i) {
SDL_DisplayMode *mode = modes[i];
SDL_Log("Display %" SDL_PRIu32 " mode %d: %dx%d@%gHz, %d%% scale\n",
display, i, mode->pixel_w, mode->pixel_h, mode->refresh_rate, (int)(mode->display_scale * 100.0f));
}
SDL_free(modes);
}
}
SDL_GetDesktopDisplayMode() and SDL_GetCurrentDisplayMode() return pointers to display modes rather than filling in application memory.
Windows now have an explicit fullscreen mode that is set, using SDL_SetWindowFullscreenMode(). The fullscreen mode for a window can be queried with SDL_GetWindowFullscreenMode(), which returns a pointer to the mode, or NULL if the window will be fullscreen desktop. SDL_SetWindowFullscreen() just takes a boolean value, setting the correct fullscreen state based on the selected mode.
Sam Lantinga