Re: Scrolling problems in GNUstep with recent Linux distributions

[Fred Kiefer]

Hi Edwin,

yes, it is strange that you seem to be the only one that experiences
this issue.

I promised some some time ago to look into this problem after coming
back from my holidays. I wanted to update my virtual Ubuntu machine and
inspect the situation there. As it turned you, I didn't even have an
Ubuntu virtual image :-(
I will have to download one, probably for Ubuntu 14.10 now, install
GNUstep on it and try with that. But that will require a lot more time
then I expected.

In the meantime cairo 1.14 has been released and I would expect that
Ubuntu will use this in a few weeks. Maybe the issue will be resolved
that way.

But none of this touches the question why it is only you, who is seeing
the issue. Maybe it is not cairo itself, but the graphics driver used?

What you could do to investigate the issue yourself is to start
debugging in the GNUstep cairo backend. If I remember correctly the
method in question is in CairoGState

- (void) compositeGState: (CairoGState *)source
                fromRect: (NSRect)srcRect
                 toPoint: (NSPoint)destPoint
                      op: (NSCompositingOperation)op
                fraction: (CGFloat)delta

As you can see there is some special handling for copyOnSelf and that is
the case you are after. You will also see special handling for a cairo
version > 1.8.0, maybe cairo fixed this bug and that code wont be needed
starting with cairo 1.13.0?

Fred


Am 25.10.2014 um 10:36 schrieb Edwin Ancaer:
> Hello guys,
> 
> is there anybody who is using Gworkspace, ProjectCenter, Gorm.... in
> short any GNUstep application on an Ubuntu 14.04 or Fedora 19/20 based
> distribution.
> 
> I'm asking because on these distributions, I'm experiencing problems
> when scrolling: the text gets blurred on the screen, the lines are no
> longer aligned...
> 
> It might be due to an unofficial libcairo version 1.13...(I must be
> carefull here or Fred Kiefer will come and kick....) in these
> distributions , but I seem to be the only person complaining, So it must
> be that 
> 
>  1. everybody is using Gnustep on older distributions or on xxxBSD, or
>     on Hurd or on anything where you can youse GNUstep, except
>     Ubuntu/Fedora....
>  2. nobody is really using gnustep, but someone is pretending it is
>     still alive, and sending all these mails on this mailing list
>  3. I'm the only person with this problem 
> 
> 
> In the last case, I will have to admit in public I'm the idiot that
> cannot even compile and install GNUstep (and I've done some
> installations the last weeks), and should be banned from using computers
> any longer
> 
> I'm not asking that anybody solves this problem, but I need to know if
> I'm really unable to install GNUstep, or that there is at least somebody
> else with the same problems... or, in case of option 2, send me a
> private mail confirming GNUstep really is a joke. I promise I won't tell
> anybody.
> 
> Hoping somebody can end this agony before it drives me mad,
> 
> Edwin Ancaer
> 
> 
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