The existing behavior helps clients that don't expect exclusive fullscreen windows to move by maintaining a consistent size and mode, however, some are aware that this can occur and want to handle mode selection themselves.
Add a hint to disable auto mode switching when an exclusive fullscreen window moves to accommodate this use case, and don't override fullscreen changes that may occur in an event watcher between the display changed event being posted and SDL running the display changed handler, as the mode switch may have already been handled there by the client.
Move hints used by Emscripten to window properties. This change will be necessary if multiple windows for Emscripten will be supported in the future.
- Added Window Create Property SDL_PROP_WINDOW_CREATE_EMSCRIPTEN_CANVAS_ID
- Added Window Create Property SDL_PROP_WINDOW_CREATE_EMSCRIPTEN_KEYBOARD_ELEMENT
- Use hint SDL_HINT_EMSCRIPTEN_CANVAS_SELECTOR as override to SDL_PROP_WINDOW_CREATE_EMSCRIPTEN_CANVAS_ID
- Use hint SDL_HINT_EMSCRIPTEN_KEYBOARD_ELEMENT as override to SDL_PROP_WINDOW_CREATE_EMSCRIPTEN_KEYBOARD_ELEMENT
- WIN_SetWindowAlwaysOnTop is always called as part of window creation (normally setting HWND_NOTOPMOST) which also set the z-order for the parent
window when child windows are created. Since HWND_NOTOPMOST is above all non-topmost windows this had the effect of reordering but not focusing
the parent window.
With ASAN enabled the existing code triggered null-pointer-dereference
in the strcmp since EMSCRIPTEN_EVENT_TARGET_WINDOW is a "fake" pointer
with the value ((const char*)2). In fixing this it was also noticed
that using the #window/#document/#screen targets as mentioned in the
docs fails since document.querySelector() returns null for them and we
should instead be mapping them to the special HTML targets provided.
External windows may call this to update the renderer size, but not pump SDL events, either by syncing or running an event loop, so the size event always needs to be synthesized for external windows. If it is wrong, the true size will be sent if/when events are processed.
The bug this appeared to fix turned out to be randomly occurring and has other causes, and the read pipe is already polled for readiness, so this extra overhead isn't necessary.
The platforms that needed this (Windows Phone and Windows RT) are no longer supported, and if this is needed in the future it should be done at the renderer level, not here.
Fixes https://github.com/libsdl-org/SDL/issues/12475
