[matplotlib-devel] Re: Bug in matplotlib_gtk ?

[Steve C. <ste...@ya...>]

On Wed, 2006-02-15 at 20:36 -0800,
mat...@li... wrote:
> Hello,
> 
>     I'm using matplotlib figures in several places at a time in my GTK
> based app (means different page in a notebook).
> I have trace a bug I partially solved but still doubting if it is a
> matplotlib bug or a bad design of my app.
> 
> Matplotlib 0.86.2
> pygtk-2.8.4
> gtk+-2.8.6
> 
> Here is the problem:
> 
> in matplotlib/backends/backend_gtk.py file, in 
> class FigureCanvasGTK (gtk.DrawingArea, FigureCanvasBase):
> ... in:
> 
>  def draw(self):
>         # synchronous window redraw (like GTK+ 1.2 used to do)
>         # Note: this does not follow the usual way that GTK redraws,
>         # which is asynchronous redraw using calls to
> gtk_widget_queue_draw(),
>         # which triggers an expose-event
> 
>         # GTK+ 2.x style draw()
>   1-   self._need_redraw = True
>   1-   self.queue_draw()
> 
>         # synchronous draw (needed for animation)
>   2-   x, y, w, h = self.allocation
>   2-   if w<3 or h<3: return # empty fig
> 
>   2-   self._pixmap_prepare (w, h)
>   2-   self._render_figure(self._pixmap, w, h)
>   2-   self._need_redraw = False
>   2-   self.window.draw_drawable (self.style.fg_gc[self.state],
>   2-                                 self._pixmap, 0, 0, 0, 0, w, h)
> 
> 
> If I use method 1- (and comment 2-) no problem, all run smoothly...
> But using the default method, switching on method 2- (and comment 1-)
> I get the followig error message when trying to redraw one of the
> figure
> (the figure is plotted correctly the first time. No change made to the
> figure, just redrawing...)
> 
> ***/python2.4/site-packages/matplotlib/backends/backend_gtk.py:298:
> GtkWarning: gdk_pixmap_new: assertion `(drawable != NULL) || (depth !=
> -1)' failed
>   self._pixmap_height)
> Traceback (most recent call last):
> ... 
>     self.canvas_leak.draw()
>   File
> "***/python2.4/site-packages/matplotlib/backends/backend_gtk.py", line
> 250, in draw
>     self._pixmap_prepare (w, h)
>   File
> "***/python2.4/site-packages/matplotlib/backends/backend_gtk.py", line
> 298, in _pixmap_prepare
>     self._pixmap_height)
> RuntimeError: could not create GdkPixmap object
> 
> Somebody has a clue ???
> 
Its difficult to say if its bug in backend_gtk.py, it depends on exactly
what your application is doing. You would need to post a minimal test
case that demonstrates the bug so we could see whats going on.

Steve

Send instant messages to your online friends http://au.messenger.yahoo.com