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Erik Tollerud wrote:
> I tested this on 0.91.2 on Ubuntu Gutsy, and wx 2.8.7.1, and found
> that when I bring up a new window, I see a black canvas and it doesn't
> draw any of the matplotlib objects until I do something like resizing
> that must explicitly call a draw at some point.
yup, same here.
I'm using wxAgg, and FigureCanvas.draw() just doesn't seem to be getting 
called when I call Figure.draw()
It looks like it's designed to work the other way -- the Window needs to 
call self.figure.draw(self.renderer) when it wants the image drawn. 
There is an efficiency to this, as the figure doesn't get rendered until 
the GUI toolkit needs it. However, having it re-render on every Paint 
call isn't right either.
So how should this work? I'd like to be able to call Figure.draw(), and 
have the figure re-draw itself - but then it needs to be able to tell 
the backend Canvas that it needs to be drawn.
It seems that the figure needs to keep a flag that indicated when it is 
"dirty", then the paint handler could check that, and call draw if need 
be. Is there one already?
This all seems a bit awkward though. I've written a bunch of double 
buffered code, and I try to do it like this:
The Paint handler only blits.
There is a draw routine that actually draws the off-screen bitmap. It is 
called:
 - when the bitmap is new, like in a Re-size event
 - when the drawing changes.
In the MPL case, then, it seems that figure.draw() should call that draw 
routine, but maybe it doesn't know anything about its canvas. Ah -- ye 
sit does - figure.canvas.
OK, so a draw_event is getting called, which I guess is where the 
drawing should happen, but I'm getting lost now!
-Chris
-- 
Christopher Barker, Ph.D.
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Chr...@no...

I tested this on 0.91.2 on Ubuntu Gutsy, and wx 2.8.7.1, and found
that when I bring up a new window, I see a black canvas and it doesn't
draw any of the matplotlib objects until I do something like resizing
that must explicitly call a draw at some point. This may be why it's
in there... perhaps some sort of checking to see if any draw has been
performed yet?
On Mon, Mar 31, 2008 at 7:58 AM, Gregor Thalhammer
<gre...@gm...> wrote:
> Dear developers,
>
> I discovered that in backend_wx.py in _onPaint(), the callback function
> for repainting a matplotlib figure, every time a repaint is done also
> the bitmap is rerendered:
>
> backend_wx.py/_onPaint():
> ...
> # Render to the bitmap
> self.draw(repaint=False)
> ...
>
> This also affects the behaviour of the wxagg backend. Rerendering and
> therefore also repainting gets quite slow if, e.g., images are included
> in the figure. I can see this by simply dragging another window across
> the matplotlibfigure. Commenting out the rerendering I get a much
> smoother behaviour. I could not observe problems except that sometimes
> some parts of the figure are not properly repainted if the matplotlib
> figure is in the background (I only tested the wxagg backend). Therefore
> it seems that this rerendering every time a repaint is performed is not
> really necessary and should be avoided.
>
> I tested this on matplotlib 0.91.2 on WinXP, Python 2.5, wx 2.8.7. I
> checked that in the current svn version the _onPaint() function is
> unchanged.
>
> Gregor
>
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-- 
Erik Tollerud
Graduate Student
Center For Cosmology
Department of Physics and Astronomy
4155B Frederick Reines Hall
University of California, Irvine
Office Phone: (949)824-2996
Cell: (651)307-9409
eto...@uc...

Dear developers,
I discovered that in backend_wx.py in _onPaint(), the callback function 
for repainting a matplotlib figure, every time a repaint is done also 
the bitmap is rerendered:
backend_wx.py/_onPaint():
...
# Render to the bitmap
self.draw(repaint=False)
...
This also affects the behaviour of the wxagg backend. Rerendering and 
therefore also repainting gets quite slow if, e.g., images are included 
in the figure. I can see this by simply dragging another window across 
the matplotlibfigure. Commenting out the rerendering I get a much 
smoother behaviour. I could not observe problems except that sometimes 
some parts of the figure are not properly repainted if the matplotlib 
figure is in the background (I only tested the wxagg backend). Therefore 
it seems that this rerendering every time a repaint is performed is not 
really necessary and should be avoided.
I tested this on matplotlib 0.91.2 on WinXP, Python 2.5, wx 2.8.7. I 
checked that in the current svn version the _onPaint() function is 
unchanged.
Gregor