[gcompris-devel] Re: refresh bug in the canvas

[Bruno Coudoin]

Le mer 21/05/2003 à 12:58, Olivier Samyn a écrit :
> For the python part, I didn't already checked if there's a python module for this foocanvas... but I'm sure that gnome-python and pygtk people will help u if we need to write a python module for this one...
> 
> I'll check about this and let you now what are the results...
> 
> For the bugs points, we could ask to he foocanvas developper some help...

I think it would be more to change our code to fit in what's foocanvas
is doing well.

> And for the other points, we could implement some functions in gameutil or something like that to replace the non available functions.
The missing functions are the affine ones. Pascal uses them to rotate
the submarine. We could find other way to achive this but that's
annoying.


> If we gain some speed I think it can be an important change so that lower resources machines will be enought to play gcompris...

I don't think so, gcompris already runs on old PC with as low as 16MB of
memory (tested with freeduc). Besides the refresh bugs, the only benefit
would be to gain some fps ;). For example, in the paratrooper, we move
the plane 4 by 4 pixels, we could move it 1 by 1 and thus have a better
'feeling'.
So to me, given the education focus of gcompris, it is not good for us
to run after this.

> 
> At last, if foocanvas is a quick evolving library and is targetted to replace gnomecanvas in some project like nautilus e could hope it'll become a new "standard"...

Future will tell.

> 
> Olivier
> 
> 
> >
> >I made the test. It is relatively easy to port gcompris to the foo
> >canvas. I have it running here by replacing all gnome_canvas to
> >foo_canvas and GnomeCanvas to FooCanvas plus the init of foo canvas libs
> >and cflags in the configure and we are done.
> >It is true that its much more faster than the gnomecanvas. Another
> >benefit is that we gain transparency (nice looking).
> >The drawback is that we loose some feature and some boards would need
> >some reworks:
> >- submarine uses the affine transform that does not exist in foocanvas
> >- python that rely on the gnomecanvas.
> >- several bugs appears all over the places, can't resize in draw,
> >keyboard entry fails in some boards, cars puzzle fails completly.
> >
> >I don't believe it's good for us to follow that path. Too much work for
> >me.
> >
> >Another point we got from Jody is that it should be possible to move to
> >gtk only and thus to gain the possibility to cross compile gcompris for
> >windows. I am personnality not a fan of this operating system and won't
> >do it myself. Now if somebody sees a benefit in this, the position is
> >open.
> >
> >Bruno.
> >
> >
> >
> >
> >Le lun 19/05/2003 à 21:15, Jody Goldberg a écrit :
> >> On Mon, May 19, 2003 at 08:52:19PM +0200, Bruno Coudoin wrote:
> >> > 
> >> > 
> >> > Does that means also that it doesn't need gnome. 
> >> It only depends on gtk.
> >> 
> >> > Going that path, I could port gcompris to gtk since I use only the
> >> > canvas, and provide a windows version ?
> >> 
> >> gnome-canvas' requirements are also only basic gtk + libart, nothing
> >> in the bonobo/gnome layers.  So that is not really a deciding
> >> factor.
> >> 
> >> > Le lun 19/05/2003 ? 19:12, Alexander Larsson a ?crit :
> >> > > On Mon, 2003-05-19 at 15:01, Bruno Coudoin wrote:
> >> > > > I am the author of gcompris and I suffer badly from a refresh bug in the
> >> > > > canvas.
> >> > > > http://bugzilla.gnome.org/show_bug.cgi?id=91583
> >> > > > I checked the CVS today and it's still there.
> >> > > > 
> >> > > > The easiest way to show evidence of the bug is the fifteen game demo in
> >> > > > libgnomecanvas/demos/canvas_demo the pieces are not refreshed after the
> >> > > > move (you move the window out of the desktop area and bring it back and
> >> > > > you see the moved items)
> >> > > > 
> >> > > > We added a bunch of gnome_canvas_update in gcompris as a workaround and
> >> > > > it's better now.
> >> > > > 
> >> > > > I don't know if gcompris is the only app to suffer this but my users are
> >> > > > disapointed :(
> >> > > > 
> >> > > > Do you know if somebody familiar with the libgnomecanvas code is aware
> >> > > > or working on this ? If not, where should I look ?
> >> > > 
> >> > > If you don't use the anti-aliased mode of the canvas you might want to
> >> > > try out the foocanvas module. It has a simplified non-aa canvas that
> >> > > performs better, redraws bettter and integrates better with gtk2.
> >> > > Applications like nautilus and gnumeric use it.
> 
> 
> 
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