canvas stuff

[Bill Haneman <Bill Haneman Sun COM>]

Hi:

Regarding gnome-canvas vs foo-canvas vs TBD-cairo-based thing: there's
some accessibility/ATK support in gnome-canvas, which is important. 
There isn't any, AFAIK, in alternatives.

Any thought of deprecating/replacing gnome-canvas needs to consider this
fact.  I also think there are problems with cairo since when I last
looked, it failed to have a nice-enough object-encapsulation API to make
ATK support feasible; that is, my impression was that cairo tended to
encourage unstructured drawing too much.

In order to make ATK support for canvas widgets possible, the widget
needs to support the notion of drawing objects at a fairly high level of
granularity, i.e. not at the level of drawing primitives.

regards

Bill