the window for which to query the text input area.
a pointer to an SDL_Rect filled in with the text input area, may be NULL.
a pointer to the offset of the current cursor location relative to rect->x, may be NULL.
true on success or false on failure; call SDL_GetError() for more information.
Threadsafety: This function should only be called on the main thread.
Get the area used to type Unicode text input.
This returns the values previously set by SDL_SetTextInputArea().