SDL3: SDL_EVENT_TEXT_INPUT never received

[rom1v]

If I press any key (a for example), I receive SDL_EVENT_KEY_DOWN and SDL_EVENT_KEY_UP, but never SDL_EVENT_TEXT_INPUT with text "a".

On Linux (tested with SDL 3.2.10 and SDL 3.2.18).

Refs Genymobile/scrcpy#6216 (comment)

[madebr]

SDL/include/SDL3/SDL_events.h

Lines 410 to 411 in bc5c9a6

	* This event will never be delivered unless text input is enabled by calling
	* SDL_StartTextInput(). Text input is disabled by default!

Did you call SDL_StartTextInput()?

[rom1v]

@madebr Thank you, it works 👍

Sorry, I had missed it in the migration doc.

Text input is no longer automatically enabled when initializing video, you should call SDL_StartTextInput() when you want to receive text input and call SDL_StopTextInput() when you are done.

I now call SDL_StartTextInput() immediately when I open the window. But:

Starting text input may shown an input method editor (IME) and cause key up/down events to be skipped, so should only be enabled when the application wants text input.

Is there a way to prevent any IME? Otherwise, it may open an IME immediately when scrcpy starts 😕

EDIT: maybe by playing with SDL_HINT_IME_IMPLEMENTED_UI (but not sure how):

SDL/include/SDL3/SDL_hints.h

Lines 1120 to 1141 in bc5c9a6

	/**
	* A variable describing what IME UI elements the application can display.
	*
	* By default IME UI is handled using native components by the OS where
	* possible, however this can interfere with or not be visible when exclusive
	* fullscreen mode is used.
	*
	* The variable can be set to a comma separated list containing the following
	* items:
	*
	* - "none" or "0": The application can't render any IME elements, and native
	* UI should be used. (default)
	* - "composition": The application handles SDL_EVENT_TEXT_EDITING events and
	* can render the composition text.
	* - "candidates": The application handles SDL_EVENT_TEXT_EDITING_CANDIDATES
	* and can render the candidate list.
	*
	* This hint should be set before SDL is initialized.
	*
	* \since This hint is available since SDL 3.2.0.
	*/
	#define SDL_HINT_IME_IMPLEMENTED_UI "SDL_IME_IMPLEMENTED_UI"

[madebr]

I don't know that much about IME, but there is this hint, which has a sensible default.

This SDL3 best keyboard practices article is also worth a read.