Re: [XBoard-devel] gtk-branch

[h.g. muller]

At 09:09 11-11-2011 +0100, Michel Van den Bergh wrote:
> Here there is some discussion about cairo and double buffering.
> See item 6.2.
>
> http://developer.gnome.org/gtk/2.24/gtk-question-index.html
>
> Michel

OK, that basically confirms my diagnosis. The move-animation
calls all create their own cairo-context outside the expose handler,
so they write to the display directly, but also trigger an expose event,
which then calls DrawPosition. For animateDragging DrawPosition
takes care of drawing the animated piece in the desired place, by
a calltoDrawDragPiece at the end, but it in oblivious of animateMoving,
so it overwrites the display with the animated piece still on the from-square
(or without atomic blast wave).

Not sure how we are expected to use cairo then. We could draw everything
from the expose-event handler, but what then would trigger the expose event?
It seems hard to use a context created in the expose handler for drawing
something outside it...