81479d8784
Some applications (and embarrassingly, testime is one of them) call SDL_StartTextInput() or SDL_SetTextInputRect() every frame. On KDE/KWin with fcitx5, this causes there to be several preedit events every frame (particularly given some of the workarounds in Wayland_StartTextInput), which slows testime down to an unusable crawl. Instead, make SDL_StartTextInput() a no-op if text input is already enabled, and cache the input rect, only changing it when the new rect is actually different. With these changes, we only get preedit events (and hence SDL_TEXTEDITING events) when the preedit string actually changes. This matches the behaviour under XWayland, and works very smoothly.
Simple DirectMedia Layer (SDL) Version 2.0
Simple DirectMedia Layer is a cross-platform development library designed to provide low level access to audio, keyboard, mouse, joystick, and graphics hardware via OpenGL and Direct3D. It is used by video playback software, emulators, and popular games including Valve's award winning catalog and many Humble Bundle games.
More extensive documentation is available in the docs directory, starting with README.md
Enjoy!
Sam Lantinga (slouken@libsdl.org)