NAME

       SDL_SetWindowHitTest - Provide a callback that decides if a window region has special properties.

HEADER FILE

       Defined in SDL3/SDL_video.h

SYNOPSIS

       #include "SDL3/SDL.h"

       bool SDL_SetWindowHitTest(SDL_Window *window, SDL_HitTest callback, void *callback_data);

DESCRIPTION

       Normally  windows  are  dragged and resized by decorations provided by the system window manager (a title
       bar, borders, etc), but for some apps, it makes sense to drag them from somewhere else inside the  window
       itself;  for  example,  one  might  have a borderless window that wants to be draggable from any part, or
       simulate its own title bar, etc.

       This function lets the app provide a callback that designates pieces of a given window as  special.  This
       callback  is  run  during  event  processing  if  we  need to tell the OS to treat a region of the window
       specially; the use of this callback is known as "hit testing."

       Mouse input may not be delivered to your application if it is within a special area; the  OS  will  often
       apply that input to moving the window or resizing the window and not deliver it to the application.

       Specifying NULL for a callback disables hit-testing. Hit-testing is disabled by default.

       Platforms  that  don't  support  this  functionality  will  return  false unconditionally, even if you're
       attempting to disable hit-testing.

       Your callback may fire at any time, and its firing does not indicate any specific behavior (for  example,
       on  Windows,  this certainly might fire when the OS is deciding whether to drag your window, but it fires
       for lots of other reasons, too, some unrelated to anything you probably care about _and  when  the  mouse
       isn't  actually  at the location it is testing_). Since this can fire at any time, you should try to keep
       your callback efficient, devoid of allocations, etc.

FUNCTION PARAMETERS

       window the window to set hit-testing on.

       callback
              the function to call when doing a hit-test.

       callback_data
              an app-defined void pointer passed to callback .

RETURN VALUE

       Returns true on success or false on failure; call

       SDL_GetError () for more information.

THREAD SAFETY

       This function should only be called on the main thread.

AVAILABILITY

       This function is available since SDL 3.2.0.

Simple Directmedia Layer                            SDL 3.2.8                            SDL_SetWindowHitTest(3)