[Xcb] R: Flickering

Alessandro Sangiuliano alex22_7 at hotmail.com
Mon Mar 1 08:45:22 UTC 2021

Hello guys,

first of all I'm really sorry if i sent 3 times the same email, it was an error because I forgot the mailer I was using on the laptop adds a delay, just my bad. Excuse me!

Now the code:

it is really simple, finally seems I got the source of the probleem; it wasn't how I handle the movement/dragging of a window, but it is the expose event that is bad implemented.

I just commented it and everything works fine with high DPI mouse too, also moving the mouse really really fast.

Now I have to find a solution on how to write a good expose event handler.


Da: Uli Schlachter <psychon at znc.in>
Inviato: mercoledì 24 febbraio 2021 20:23
A: alex22_7 at hotmail.com <alex22_7 at hotmail.com>; xcb at lists.freedesktop.org <xcb at lists.freedesktop.org>
Oggetto: Re: [Xcb] Flickering


Am 24.02.21 um 12:24 schrieb alex22_7 at hotmail.com:
> Actually I noticed that on moving a window clicking on the title bar I have some flickering.

Looks to me as if the window is moved offscreen and then quickly again
moved to its "proper position". I'd look at some tracing output to
figure this out, e.g. via xtrace (also known as x11trace) on your WM. Or
on an app in question to see where it is moved to.

Alternatively, you could do some printf-debugging and print the window
position before every xcb_configure_window() call to see where it is
being moved to.

I can't really read objc, but... where is this moving of windows
implemented? I tried searching for xcb_configure_window(), but all the
hits don't seem relevant to "move by mouse".

- He made himself, me nothing, you nothing out of the dust
- Er machte sich mir nichts, dir nichts aus dem Staub
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