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Paul Novak wrote:
> A few weeks ago there was a discussion about putting scatter symbols in 
> the legend (see 
> http://www.nabble.com/Show-shapes-on-scatterplot-legend--to15744380.html).
> 
> I would like to implement scatter symbols in the legend, but I am having 
> some problems doing so. In the function _get_handles in legend.py, the 
> symbol can be placed in the legend by doing something like:
> 
> for path in handle._paths:
> xy = path.vertices
> p = Polygon(xy)
> 
> The problem is that the polygon that gets drawn is the wrong size and 
> aspect ratio. It would seem that this would call for some sort of 
> scaling or transform to make the symbol the proper size, but I need some 
> assistance or a pointer to documentation on how to do this.
> 
> Thanks,
> 
> Paul Novak
> 
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Hi,
since I'm also very interested in this functionality I tried it myself. 
What I found out is the following:
 It appears that one transform is missing when just using the 
path.vertices. This is the transform that places the polygon at the 
correct position within the legend and scales it. Here is the 
code-fragment (from legend.py) that I currently use:
 elif isinstance(handle, RegularPolyCollection):
 if self.numpoints == 1:
 xdata = npy.array([left])
 for path in handle.get_paths():
 xy = path.vertices
 p = Polygon(xy)
 x = min(xdata)
 y = y-0.5*HEIGHT
 bbox = Bbox.from_bounds(x, y, HEIGHT/4., HEIGHT/4.)
 if 0:
 p = Rectangle(xy=(min(xdata), y-3/4*HEIGHT),
 width = self.handlelen, height=HEIGHT/2,
 )
 p.set_facecolor(handle._facecolors[0])
 if handle._edgecolors != 'None':
 p.set_edgecolor(handle._edgecolors[0])
 self._set_artist_props(p)
# HERE IS THE ADDITIONAL TRANSFORM FOR THE POLY
 p.set_transform( BboxTransformTo(bbox) + 
p.get_transform() )
 p.set_clip_box(None)
 p.set_clip_path(None)
# FOR DEBUGGING
 print p.get_transform()
 ret.append(p)
This seems to works more or less, BUT NOT when rescaling the Figure 
Window. Then again the polygons get streched...
Manuel

On Mon, Mar 10, 2008 at 11:22:26PM -0400, Jae-Joon Lee wrote:
> I mostly work in an interactive shell (ipython), and if I simply call
> a blocking function (like raw_input)
> from the prompt, it also blocks the event loop of the matplotlib gui backend
> (it happens for GtkAgg, but not for TKAgg. I'm not sure with other
> backends, but I thought
> TKAgg is a special case.)
> So I wanted to call a raw_input (or other blocking function) in an
> interactive shell
> without freezing the figure.
> Hmm, maybe I'm missing something and there has been an very easy way to do it.
> My understading was that the gui event loop waits (without processing
> gui events)
> until the commands entered in the prompt finish.
Sorry, I got lost in dealing with urgent problems again.
I can't spend too much time looking at this issue, but I would like to
confirm that you do seem to have a use-case here that I cannot solve with
something simpler. If other people agree, I think we should move forward
with your solution.
Sorry for the slow response time,
Gaël