Re: bug in Cairo or Gtk - peculiar behaviour on resizing or exposing window

[N James Bridge <james xmas demon co uk>]

On Sun, 2010-11-14 at 11:17 +0000, James Morris wrote:
> On 13 November 2010 22:18, N James Bridge <james xmas demon co uk> wrote:
> > I am hoping someone will have the time to look at this. I have been
> > developing a gtk/cairo program to draw views of the Mandelbrot set. ...
> > I am using gtk2-2.22.0-1.fc14.1.x86_64, cairo-1.10.0-2.fc14.x86_64 and
> > gcc-4.5.1-4.fc14.x86_64
> >
> > So, first: have I done something wrong (probably in draw_iter())?
>
> I can't see anything wrong exactly. I tried explicitly initializing z
> in draw_iter with z.x = cc.x; z.y = cc.y, and used
> gtk_widget_queue_draw instead of gdk_window_invalidate_rect but both
> of these made no difference. I also added some printf statements to
> check what's happening. For the values of cc, the code never returns
> in the first for loop, and the values of z.x and z.y after both loops
> never changes other than when cc does. In other words, the drawing may
> change, but z.x and z.y after both loops does not. The next thing I'd
> try would be to run it through valgrind but I need to reboot to do
> that as valgrind is unusable on my current system.
>
> james.
Thanks for input. I assume you did see the same error in drawing - some
areas inside the drawing come out solid black?

I will have to look up valgrind. All of this is a big learning exercise!

NJB