Subject: bug#1867: Resizing window causes text flickering when using antialiased font on X

From: Glenn Morris <[email-masked]>
Date: Tue, 04 Oct 2011 21:13:39 -0400

Bo Lin wrote:

> 1. Choose a font FONTNAME which supports antialiasing. Confirm
> antialiasing is turned on for FONTNAME in fontconfig:
>
> $ fc-match -v FONTNAME |grep antialias
> 	antialias: FcTrue(w)
>
> 2. emacs -q
> 3. M-: (set-face-attribute 'default nil :font "FONTNAME")
> 4. C-x 3 C-x 2
>
> Now there are three windows. We'll name the upper-left window 1,
> lower-left window 2, and the right window 3.
>
> 5. C-x b *scratch* RET C-x o C-x b *Messages* RET C-x o C-h i
> 6. Using mouse, quickly drag mode-line of window 1 up and down.
>
> Observe how text in window 1 and 3 flicker as windows 1 and 2 are
> resized. The main point is that window 3, though totally unaffected by
> the resizing of windows 1 and 2 and showing a different buffer, is still
> been constantly redrawn. This quite annoying, as even when the
> mini-buffer window resizes, which happens quite frequently, will cause
> the whole frame to flicker.
>
> This flickering does *not* occur if using old X core fonts. To confirm,
> start with `emacs -q -fn fixed' and repeat steps 4-6.
[...]
> In GNU Emacs 23.0.60.7 (i686-pc-linux-gnu, GTK+ Version 2.14.4)
>  of 2009-01-12 on unicorn
> Windowing system distributor `The X.Org Foundation', version 11.0.10502000

I don't seem to be able to reproduce this. Do you still see this with
the latest version of Emacs?