Re: Ugly flickering in some views

[Germán Arias]

On 2012-01-23 21:16:01 -0600 Eric Wasylishen <address@hidden> 
wrote:

> Thanks for the info.. this is bad because it sounds like the 
> NSCopyBits is 
> causing flickering.
>
> I have another debugging request:
> -update gui/back again
> -verify the flickering is back.
> -open back/Source/cairo/CairoContext.m
> and change this section:
>
> //#    define _CAIRO_SURFACE_CLASSNAME XGCairoSurface
> //#    include "cairo/XGCairoSurface.h"
> //#    define _CAIRO_SURFACE_CLASSNAME XGCairoXImageSurface
> //#    include "cairo/XGCairoXImageSurface.h"
> #    define _CAIRO_SURFACE_CLASSNAME XGCairoModernSurface
> #    include "cairo/XGCairoModernSurface.h"
>
> to this:
>
> //#    define _CAIRO_SURFACE_CLASSNAME XGCairoSurface
> //#    include "cairo/XGCairoSurface.h"
> #    define _CAIRO_SURFACE_CLASSNAME XGCairoXImageSurface
> #    include "cairo/XGCairoXImageSurface.h"
> //#    define _CAIRO_SURFACE_CLASSNAME XGCairoModernSurface
> //#    include "cairo/XGCairoModernSurface.h"
>
> -make and install back, and try fisicalab again.

This change solves the problem.

> I'm assuing you're using the cairo backend. I'm curious if changing 
> from 
> XGCairoModernSurface to XGCairoXImageSurface will fix the problem. 
> Also it 
> might be worth trying art or xlib, and see if you still get the same 
> flickering.

Yes, I'm using cairo. And with xlib and art all works fine. The 
problem is only with
cairo. I don't understand this problem. But, for example, the 
fisicalab's chalkboard
works fine. Even when is basically the same. An NSView with a lot of 
buttons that
can display images. The only difference is that its content isn't 
copied from another
window. And why this problem occurs only when I move the scrollbar to 
down?

Thanks.

> Thanks
> Eric