[Cairo] AA-Artifacts during/after gameoflife

Christof Petig christof at petig-baender.de
Wed Nov 19 01:02:00 PST 2003

Owen Taylor schrieb:
> On Tue, 2003-11-18 at 13:10, Christof Petig wrote:
>>What about semi transparent widgets? I was under the impression that 
>>this needs a client side rendering library for gdk (which is what cairo 
>>can do). Semi transparent toplevel windows are a different problem 
>>(solved by keith's X server) but the current gdk implementation uses a 
>>lot of subwindows (which might also get semitransparent under said 
>>server without needing cairo?).
> There aren't many subwindows in GTK+ - the only widgets with
> Input/Output subwindows are:
>  - Widgets that scroll (Viewport, TextView, TreeView)
And HandleBox IIRC (though this one does not scroll).
>  - Entry (I had concerns about breaking input methods by not giving
>    each entries it's own widget)
So making an Entry an InputOnly Widget in 2.3 will fix this, won't it?
>  - Menubar (this one slipped through the cracks)
> Any other widget can be made semi-transparent simply by drawing 
> semi-transparently. With current GDK API's, the only  semi-transparent
> drawing api is gdk_draw_pixmap(). 

So IIRC I can not yet say that a Toolbar has "20% opaque white" as it's 
background color or a Label has "80% opaque black" foreground color. 
This would require decent gdk support which is not planned before cairo 
is integrated into gdk.

Is this correct? (should we cc gtk-devel?)

>  http://people.redhat.com/~otaylor/gtk/lots-of-alpha.png

But I read in your post that semi transparent backgrounds are only 
possible using images/pixmaps not GdkColors.

> Entries will have to weight for the COMPOSITE extension; can't go
> window => no_window and retain compatibility.

But input only windows should give the desired effect now, shouldn't they?


More information about the cairo mailing list