Emacs scrolling (redisplay) is very slow in Windows XP after the font end enabled

Emacs scrolling (redisplay) is very slow in Windows XP after the font end enabled

[brianjiang]

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Emacs scrolling (redisplay) is very slow in Windows XP after the font backend enabled.
 
e.g., if I open a file （quite large）, when I press PageDn/PageUp to scroll it, there is an uncomfortable delay in the redisplay. If I hold down the PageDn/PageUp for a while, the delay is even worse and Emacs will lose response for a while.
 
In Emacs-22.2 and the 23 version where the font backend disabled, the scrolling is very fluent when I hold down the PageDn/PageUp key.
 

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Re: Emacs scrolling (redisplay) is very slow in Windows XP after the font end enabled

[Lennart Borgman (gmail)]

brianjiang@gdnt.com.cn wrote:
> Emacs scrolling (redisplay) is very slow in Windows XP after the 
> font backend enabled.
>  
> e.g., if I open a file （quite large）, when I press PageDn/PageUp to 
> scroll it, there is an uncomfortable delay in the redisplay. If I hold 
> down the PageDn/PageUp for a while, the delay is even worse and Emacs 
> will lose response for a while.
>  
> In Emacs-22.2 and the 23 version where the font backend disabled, the 
> scrolling is very fluent when I hold down the PageDn/PageUp key.

I do not know if you follow this list, but it has been discussed here
quite a few times. Some people are working on this (many thanks!) and my
impression is that it is getting better and better, but there is still a
bit left.

If you want to report any specific problem in this area I think you need
a very fresh checkout from the CVS for the report to be usable.

Re: Emacs scrolling (redisplay) is very slow in Windows XP after the font end enabled

[Jason Rumney]

Lennart Borgman (gmail) wrote:

> I do not know if you follow this list, but it has been discussed here
> quite a few times. Some people are working on this (many thanks!) and my
> impression is that it is getting better and better, but there is still a
> bit left.
>   

I don't think anyone has been specifically working on performance
optimization up until now. We are still ironing out bugs that cause
display problems and crashes.

RE: Emacs scrolling (redisplay) is very slow in Windows XP afterthe font end enabled

[brianjiang]

> If you want to report any specific problem in this area I think you
> need a very fresh checkout from the CVS for the report to be
> usable. 

I did checkout a very fresh version (Jun 16) to report this
problem. The problem is still there. Since the --disable-font-backend
option has been eliminated, this performance problem really frustrates
the Windows users now. As I know, many people stop checking out the
new version from CVS now.

Any way, many thanks to the people contribute to Emacs :-)