Re: xterm.c (x_clear_frame) - commented out call to XClearWindow

[Chong Yidong]

Jan Djärv <address@hidden> writes:

> The uncommented XClearWindow in x_clear_frame must be there so I
> activated it again...  Flickering is almost unavoidable for Gtk as we
> bypass the normal Gtk drawing stuff.

Obviously, I disagree.  AFAICT this has nothing to do with GTK.

The XClearWindow is obviously unnecessary if Emacs covers the entire
frame area when drawing glyph strings during redisplay, since the glyph
strings apply the background color.  The problem here arises because
there are some areas of the frame not drawn over durig redisplay,
e.g. the leftover spaces to the bottom and right in fullscreen mode.
The fact that these areas are unpainted may be regarded as a bug.  A
suitable temporary work-around would be to paint over them---but
painting the entire frame is clearly an overreach.

> Just doing
> (set-background-color "green")
>
> and then
>
> (set-background-color "white")
>
> leaves big chunks of green where there is no text unless x_clear_frame
> does its job.

I can't reproduce this at all.