Re: Emacs GTK scroll-bar flickering

["Jan D." <jan.h.d@swipnet.se>]

Miles Bader wrote:
> Hmmm, today's CVS seems _slightly_ better -- at least, cursor movement
> doesn't cause flickering.  However, the behavior when the buffer size
> (or window configuration, etc) changes is if anything, worse now: it
> looks like whenever the scrollbar gets updated (even by a single
> character change in the buffer), it's getting completely cleared and
> redrawn about 4 or 5 times, with each redraw being very obvious and slow
> (this is certainly exacerbated because I'm using a pixmap theme, but
> this theme is not a problem with other GTK apps).
> 
> Something really seems drastically wrong here, since other GTK apps [I'm
> using `gedit' for comparison] have basically no flickering, slowdown, or
> obviously excessive redraws when they update the scrollbar.  It seems as
> if emacs is somehow completely regenerating the scrollbar whereas other
> apps are using some sort of interface that allows incremental updating
> or the like.


I made some changes, please try them out.

There are some of the redraws that can't easily be eliminated.  GDK (the layer 
under GTK) does its own event buffering, and releases the events when the GTK 
event loop is entered and there are no events to process.  Since Emacs are not 
using a pure GTK loop, there might be a very long time before GTK gets a chance 
to notice this.  So Emacs must force out these events.  Ideally they should not 
generate any more redraws, just make them happen earlier, but experience shows 
that we do get redraws.

	Jan D.