Re: GdkGLContext for Mac OS X Quartz backend patches

[Emmanuel Briot <briot adacore com>]

> The cairo patch is provisional and may need further work; basic problem is that a quartz surface created 
> for a window takes its device scale into account on the Quartz (CGContext) side but the cairo side doesn't 
> know about it and treats it like a 1x-scaled surface. This was leading many things to 'work' in GTK+ due to 
> the gdk-quartz cairo stuff not actually applying device scale on surfaces either... but offscreen surfaces 
> used for scrolling and GL rendering ended up really treated as 1x leading to low-resolution widgets being 
> displayed in some places. In my gtk+ patches I fix gdk-quartz to set the window's device scale resolution 
> on the cairo surface, which requires this cairo fix (or one very like it). Possibly the cairo fix should 
> set the cairo-level device scaling on the surface as well, which I think would be redundant in the GTK+ 
> case but might be a wise default.

+1 for the patch to both cairo and gdk.

That indeed fixed the issue of text appearing fuzzy as soon as the scrollbars are displayed: for instance, a 
one-line GtkTextView
appears crisps, but as soon as we enter enough text to start scrolling, the display is fuzzy on Retina 
display.

Thanks
Emmanuel