Add Window.focused

[damusss]

stubs, docs, test included.

Can it be done with events?

Yes. but you need to keep an extra variable and it's more annoying. If there is a simpler way, why not have it?

Is this different from the other focus-related api?

Yes. Other functions such as event.get_grab, mouse/key.get_focused return True if the state is true for any open window. This attribute only returns true for the current Window object, which is important if you need to redirect interactions to one window only (for example, get_pos returns the relative pos of the current window, so you need a way to decide which window can use the get_pos or get_pressed results. I have a real life example if needed)

Why Window.focused?

I am only following the attribute convention of Window such as mouse_grabbed, keyboard_grabbed.

Test code

import pygame

pygame.init()
win = pygame.Window("focused test", (500, 500))

while True:
    for e in pygame.event.get():
        if e.type == pygame.WINDOWCLOSE and e.window == win:
            pygame.quit()
            raise SystemExit

    print(win.focused)
    win.flip()

    # play around with the window, focus other windows, check the terminal

[ankith26]

LGTM, thanks 🎉

[bilhox]

LGTM 🎉