Re: Alpha-composition of two pixmaps

["Dmitry M. Shatrov" <erdizz rambler ru>]

Michael L Torrie wrote:

> On Thu, 2004-10-28 at 18:18 +0400, Dmitry M. Shatrov wrote:
>  
>
> > GdkPixbuf is not what I need, cus it is by definition slow. I guess, 
> > drawing pixbufs is optimized for Render just because it is frequently 
> > used (all icons, for example), and alpha-drawable-to-drawable is too 
> > special to even bother about it.
> >    
>
> It's not slow by definition.  Anyway it does use render directly.  So if
> you have an accelerated render driver in the X server, it will be plenty
> fast.  If not, then it will be slow even if you called render directly.
>
>  

Well, being more correct, it's not fast enough (I realize, it does what 
it is intended to do -- pixel format abstraction -- pretty effectively). 
As I see XShm and XRender bits in gdk_draw_pixbuf, maybe it is its pixel 
transformation that is too much overhead for my particular application: 
there is a pair of non-filled wire-images, and only pixels covered by 
several thin lines need transformation. To have more freedom, I'm using 
GdkImage and work with pixel formats directly, and in combination with 
XShm this provides good performance even for 1280x1024 fullscreen.

> > Looks like it worths adding a pair of calls to gdk-x11 and post it to 
> > gtk-devel..
> >    
>
> I don't think Render should be exposed in gdk.  For one it's just a
> backend method, and is not available on all platforms nor is it
> available on all X servers.
>
>  
Don't you mean all XOrg >R6.8 window composition bits are not for gdk as 
well?

E. g. I'm dreaming about non-rectangular gnome-panel. Just imagine, a 
sector in you right-bottom corner with a nice small hide button in the 
corner also :) Such things are becoming nearly real and can't be missed! 
And among these extensions is XRender.

Well, maybe it's more correct to add something like "an extension" to 
gdk? Is there a proper procedure for adding platform-specific stuff, too 
special for general API but still highly important?

> > Dmitry
> >