Looking for colourful advice

[Joseph Scheuhammer <clown utoronto ca>]

Hi,

Gnome-mag has a "cross-hair" feature for helping users find the mouse 
cursor.  An example graphic can be viewed here:
http://clown.atrc.utoronto.ca/aegis/GS-Mag/CrossHairs.png

The issue is that the cross hairs cannot obscure what lies beneath 
them.  As you can see in the png, the colours of the cross hair are 
blended with the background.

Is colour blending possible within GnomeShell?  My approach would be to 
use clutter texture objects to form the cross hairs -- are there colour 
blending functions for texture objects?  I've looked at the online 
documentation (http://www.clutter-project.org/docs/clutter/stable/), and 
found transparency manipulations, but that's probably not enough.  
Should I be diving into COGL?  Looking somewhere else?

Any advice would be appreciated.

--
;;;;joseph

'Clown control to Mao Tse Tung.'
 - D. Bowie (misheard lyric) -