Strange scaling issue

["Till Harbaum" <lists harbaum org>]

Hi,

i am facing an issue with my goocanvas based mapping application. So far goocanvas always
worked well, but there's no an issue i cannot explain.

This is happening when i try to display small icons. If you've seen screenshots
of my application you have perhaps seen those little red and green circles. These are "nodes", e.g.
points defining a road or points representing a restaurant or so. I'd now like to use small icons 
for these (in fact the styling presets i am importing from another application include icons).

Since the default icons are too big i'd like to scale them and this is where things go wrong. As
long as i just load the icon images without scaling them they work fine. They still scale 
perfectly with zooming and all other non-image nodes being in the same group are also 
displayed just well.

But if i change the items scale to e.g. 50% by doing 
   goo_canvas_item_scale(item, 0.5, 0.5);
strange things start to happen. 

No icon is displayed anymore regardless what zoom i set.  And other nodes (all simple circles) 
being part of the same canvas group aren't displayed anymore above a zoom level of ~ 1.0.

This only happens on the n810 (arm), not on the Maemo x86 emulation on the PC and not on the 
desktop PC running stock ubuntu. This also happens regardless  of the goocanavs version. I've 
seen this with ubuntus goocanvas 0.9 as well as a goocanvas 0.13 compiled by me.

I know that you won't probably be able to help since the only setup showing these symptoms is the
n810 based one. It may very well be an issue with the underlying graphics libraries which have a 
problem scaling images down or so. The only thing that makes me think that perhaps the goocanvas
itself is involved is the fact that other items in the same group are affected. And only these are affected
and no other items. Are these groups a pure goocanvas internal thing or are these somehow exported
to underlying graphics layers? E.g. in form of seperate windows/drawables/whatever?

I can do simple tests with goocanvas as i was able to build a package for the n810 from scratch from
the 0.13 tarball. 

This is not really urgent as the icons are pretty ugly, anyway :-)

Till