al_update_display_region
void al_update_display_region(int x, int y, int width, int height)
Does the same as al_flip_display, but tries to update only the specified region. With many drivers this is not possible, but for some it can improve performance.
The ALLEGRO_UPDATE_DISPLAY_REGION option (see al_get_display_option) will specify the behavior of this function in the display.
See also: al_flip_display, al_get_display_option
Examples: ex_font
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