Re: [Goocanvas-devel] custom item, python issues

[Brandon Lewis <brandon_lewis berkeley edu>]

It's not that there's anything wrong with it, it's that I can't run it because 
the required libsvgr-python package doesn't seem to be available on Ubuntu. Just 
by looking at the source code I cannot tell what I am doing wrong and this 
example is doing correctly, or if the same problem exists in both programs.

--Brandon

Gian Mario Tagliaretti wrote:
> On Mon, Dec 8, 2008 at 6:59 PM, Brandon Lewis
> <brandon_lewis berkeley edu> wrote:
>
> Hi Brandon,
>
> I've cc'd goocanvas-list on gnome since we are using that one now.
>
> > I am trying to write a custom python canvas item derived from
> > GoocanvasItemSimple. It overrides the following methods
> >
> > * do_simple_update
> > * do_simple_paint
> > * do_simple_is_item_at
> >
> > The item displays initially, but if changed(True) is called for any reason, the
> > item disappears. I am not sure what the true cause is, but in my debugging
> > efforts I have learned that the item's bounds are all wrong. The boundary
> > coordinates always increase before every update, no matter what values I
> > assigned to them in a previous update. I have even tried setting the bounds to
> > all zeros, just to see what effect this might have.
> >
> > What I really would like to see is a python example of an item derived from
> > ItemSimple that also overrides do_simple_{update,paint,is_item_at} so that I can
> > see if I'm doing something wrong. I have looked at the C code for the Rect item,
> > and I can't see anything obvious that I am doing wrong.
>
> there is a custom-svg.py example that uses update, paint and
> is_item_at, isn't that one useful?
> http://svn.gnome.org/viewvc/pygoocanvas/trunk/demo/customs/custom-svg.py?view=markup
>
> cheers