Re: [Matplotlib-users] Plot moves while using the "Zoom to rectangle" button

[Benjamin R. <ben...@ou...>]

On Sat, Jul 24, 2010 at 12:17 PM, João Luís Silva <js...@fc...> wrote:

> On 07/13/2010 02:31 AM, John Hunter wrote:
>
>> On Mon, Jul 12, 2010 at 8:05 PM, John Hunter<jd...@gm...>  wrote:
>>
>>> All of which is discouraging: we both see bugs but different ones on
>>> linux, the appearance of the bug is caused by adding a combobox which
>>> is not used (on my system), the bug appears on some platforms (linux)
>>> but not others (win) and it appears for both gtk and gtkagg.
>>>
>>
>> The last thing I'll add for now is that my bug, the black pixel noise
>> (fills the axes window when motion starts in a zoom-to-rect event)
>> which may be unrelated to your bug, is happening in
>> backend_gtk.NavigationToolbar2GTK.draw_rubberband in the pair of
>> calls:
>>
>>   # this is used to copy the background that the zoom to rect
>> "rubberband" will be drawn over
>>   self._imageBack = axrect, drawable.get_image(*axrect)
>>
>>   # this is used to restore the background before redrawing the
>> rectangle for the zoom box
>>   drawable.draw_image(gc, imageBack, 0, 0, *lastrect)
>>
>> Since the bug is only exposed when a combo box is added to the
>> hierarchy, and appears to be platform or gtk specific, I'm suspecting
>> a gtk bug at this point.  But I don't have anything conclusive or a
>> minimal example which I could use to post to the gtk list.  The mpl
>> calls and values (axrect, lastrect, etc) look correct on inspection.
>> Somehow the call to drawable.get_image is getting a buffer full of
>> noise if and only if the combobox is added to the vbox.
>>
>> JDH
>>
>
> From what I could understand from the pygtk documentation get_image /
> draw_image are client-side operations. In particular:
>
> "If the source drawable is a Gdk::Window and partially offscreen or
> obscured, then the obscured portions of the returned image will contain
> undefined data."
>
> Anyway they recommend using Pixmap, which is server-side and a offscreen
> drawable. I've attached a patch that replaces the get_image / draw_image
> with Pixmap operations and fixes this bug. I've tested this patch on Linux
> and Windows.
>
> Regards,
> João Luís
>

The patch works for me.  I am using the mpl from svn.

Ben Root