[sugar] Need guidance from a Pygtk guru

[Tomeu Vizoso]

Sorry but cannot think of any worthwhile suggestion to give you right now.

Have you made any advances on the last two days?

Regards,

Tomeu

On Sun, Oct 5, 2008 at 4:19 PM, Pierre Métras <genepi at sympatico.ca> wrote:
> Hello,
>
> I've learnt Python and Pygtk writing the Clock activity
> (http://wiki.laptop.org/go/Clock_activity) and I'm now adding a new feature
> to write the time in full letters to help children learn how to write and read
> it. The clock has different display modes and the default one is to use a SVG
> background. I encounter a strange behavior and I don't know where to look at
> to correct it.
>
> The display of the clock activity is composed of a gtk.VBox with a custom
> ClockFace widget at the top, and a gtk.Label where I write the current time.
> The user can decide to hide/show the written time with an icon in the
> toolbar.
>
> When the Label is not displayed, the XO has enough power to update the
> ClockFace widget in less than 1 second, which is nice and what you would
> expect from a clock with a hand for seconds.
>
> But when the user selects to show the time and the code show() the gtk.Label,
> the ClockFace widget takes more than 1 second to refresh. The whole activity
> becomes unresponsive and it is even difficult to move the mouse to close it.
> Gtk timer event every seconds can't follow up...
>
> I've tracked the problem to these lines:
>
>           if radius != self._cache_radius:
>                f = open("clock.svg", "rb")
>                svg_data = f.read()
>                f.close()
>
>                loader = gtk.gdk.PixbufLoader("svg")
>                loader.set_size(int(2 * radius), int(2 * radius))
>                loader.write(svg_data)
>                loader.close()
>
>                self._cache_pixbuf = loader.get_pixbuf()
>                self._cache_radius = radius
>
>            pixbuf = self._cache_pixbuf       # 1.1
>            ct = gtk.gdk.CairoContext(context)
>            t12=datetime.now() # PME
>            ct.set_source_pixbuf(pixbuf, x - radius, y - radius)  # 1.2
>
>            t13=datetime.now() # PME
>            context.paint()          # 1.3
>            t14=datetime.now()
>            print "PME %s 1.2->1.3=%ss 1.3->1.4=%ss" % (t14, t13-t12, t14-13)
>            context.stroke()
>
> Without the gtk.Label displayed, a typical log trace is:
>
> PME 2008-10-04 13:01:15.031723 +update_cb
> PME 2008-10-04 13:01:15.033482 +draw
> PME 2008-10-04 13:01:15.348868 1.2->1.3=0:00:00.231589s
> 1.3->1.4=0:00:00.083030s
> PME 2008-10-04 13:01:15.354891 -draw
> PME 2008-10-04 13:01:15.355902 -update_cb
>
> The whole ClockFace update takes 0.32s.
> ct.set_source_pixbuf call lasts 0.23s and context.paint one 0.08s.
>
>
> Whenever the gtk.Label is shown, the pattern is totally different. Here is a
> not so extreme log (I've kept only the significant lines):
>
> PME 2008-10-04 10:48:42.025741 1.2->1.3=0:00:00.354320s
> 1.3->1.4=0:00:01.146650s
> PME 2008-10-04 10:48:43.539496 1.2->1.3=0:00:00.307176s
> 1.3->1.4=0:00:01.196331s
> PME 2008-10-04 10:48:45.074410 1.2->1.3=0:00:00.297737s
> 1.3->1.4=0:00:01.212910s
> PME 2008-10-04 10:48:46.573627 1.2->1.3=0:00:00.311503s
> 1.3->1.4=0:00:01.176982s
> PME 2008-10-04 10:48:48.091777 1.2->1.3=0:00:00.364210s
> 1.3->1.4=0:00:01.143602s
> PME 2008-10-04 10:48:49.595859 1.2->1.3=0:00:00.342134s
> 1.3->1.4=0:00:01.151180s
> PME 2008-10-04 10:48:51.082667 1.2->1.3=0:00:00.270270s
> 1.3->1.4=0:00:01.205943s
>
> Now, ct.set_source_pixbuf call lasts 0.1s more and context.paint 1.1s. I've
> even samples where the context.paint() call lasts 2.5 seconds!
>
> As I've said, this strange behavior seems to occur only when the ClockFace
> widget paints SVG. In the other display modes, the painting is drawn in the
> code. I've seen it in 8.2-761 and still in candidate-767.
>
> I've spent the last few days triying to find a reason for it, reading Gtk and
> Pygtk docs, upgrading my XO to various releases and trying alternatives in
> the code, without success. Has someone some ideas of what's happening and how
> I could solve it?
>
> Thanks
> -- Pierre Métras
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