Re: Drawing on top of GnomeCanvas?

[Gustavo Carneiro <gjc inescporto pt>]

On Mon, 2002-05-20 at 14:34, iain wrote:
> On Mon, 2002-05-20 at 11:46, Gustavo Carneiro wrote:
>
> >   No no! I want to perform a rubber-banding effect using XOR lines. I
> > *have* to draw at any time, in response to mouse events. I'm drawing but
> > I cannot see anything. Any suggestion?
>
> Because as soon as an expose happens, it's lost.
> Instead of drawing in response to mouse events, force an expose in
> response, and draw in the expose.

  But why would an expose event occur to erase what I had drawn? I mean,
expose events don't come out of thin air, they are generated for some
reason, usually by the X server. When I move the mouse, that shouldn't
generate expose events... unless some canvas item is being updated...
hm..
  I'm beginning to see the problem...
  I was trying to add a rubber-band selection mode with XOR lines to
nautilus, to improve its performance (selecting file in nautilus is
painful, even if you have a fast video card), but I see it may prove to
be more difficult than I expected. But I'll give it another try soon...

  Thanks.

-- 
Gustavo João Alves Marques Carneiro
<gjc inescporto pt> <gustavo users sourceforge net>