About gtk/cairo integration.

[Jost Boekemeier <jost2345 yahoo de>]

Hi,

there seems to be a consensus that the integration of cairo should
expose cairo_t to the users.

The problem with this is that once you expose cairo_t, you don't have
the chance to allow retained mode rendering in future versions of
gtk/gdk: In cairo the tesselation of shapes into low-level trapezoids
occurs early; because of this cairo surfaces cannot be used to hold a
"szene graph" much larger than the physical screen, they consume too
much memory (same problem that we have with huge gtkviewport childs
today).

Some gtk widgets (at least gtkviewport in 2.2.4) already draw directly
to their window outside the widget_paint() callback.  Although this may
be a bug at the moment, I think a future version of gtk should allow
retained mode rendering.


Jost