matplotlib-users Mailing List for matplotlib

Andrew,

Sure enough.  I did not pay a lot of attention to the zoom part of 
pan/zoom mode with fixed aspect ratio because it doesn't make much sense 
to me--it is trying to change the aspect ratio, while the aspect-ratio 
code is desperately trying to keep the aspect ratio fixed. The solution 
is probably to redefine what the right-button-event does in the fixed 
aspect ratio case. It should either be disabled, or arranged so that 
motion to the right and/or up zooms in and to the left and/or down zooms 
out.  What do you think it should do?

Left-button pan is definitely broken for horizontal motion.

I think what we have is not a single simple bug, but a whole set of 
bugs.  It seems to be difficult to fix one thing related to aspect-ratio 
handling without breaking something else for interactive drawing.  That 
probably means the overall design is bad.  When I can, I will take 
another look and see if I can patch it up, but it won't be right away. 
If you can find a solution, that would be great.

Eric



Andrew Straw wrote:
> I'm having trouble with axis('equal') myself -- I'm happy to take a look
> in the source, but maybe it's a simple and easy bug. The issue I'm
> having is readily apparent with examples/axis_equal_demo.py -- using the
> pan/zoom mode and holding the right-mouse button down to zoom, I notice
> several issues:
> 
> 1) moving left-and-right seems to affect the position, not the zoom level
> 2) moving up seems to zoom in (as expected)
> 3) moving down zooms out as expected, but past a certain point, only the
> vertical axis gets re-scaled and breaking the equal-aspect.
> 
> Eric Firing wrote:
> 
> 
>>Mike,
>>
>>I thought all the aspect handling was finally working correctly.  If
>>you generate a simple example, I will take a look.  The simpler the
>>better, of course.  I presume you are working with a recent svn version.
>>
>>Eric
>>
>>Michael P. Mossey wrote:
>>
>>
>>>I'm using this aspect mode:
>>>
>>>      axes.set_aspect( 'equal', adjustable='datalim' )
>>>
>>>With several xy line plots on the axes, autoscaling doesn't seem to
>>>occur properly. It cuts off part of the data. Is this a known issue?
>>>I don't have a simple script to replicate it---I'll have to pull that
>>>out of a larger program---but just wanted to check if it is known. I
>>>don't see anything in the bug tracker.
>>>
>>>Mike
>>>
> 
> 

>>>>> "Jochen" == Jochen Voss <li...@se...> writes:


    Jochen> By the way: does anybody know how to move a patch in
    Jochen> matplotlib?  set_data works for lines, but what works for
    Jochen> patches?

This should be easier, but here's an example with a regular polygon --
it is quite easy to generalize this to any patch...

Use the blit techniques described on the animation wiki if you want to
make this significantly more efficient

from matplotlib.patches import RegularPolygon
from pylab import figure, show, nx

class MyPoly(RegularPolygon):

    def __init__(self, *args, **kwargs):
        RegularPolygon.__init__(self, *args, **kwargs)
        self.offsetx = 0
        self.offsety = 0
        self.x, self.y = map(nx.array, zip(*RegularPolygon.get_verts(self)))
        
    def get_verts(self):
        x = self.x + self.offsetx
        y = self.y + self.offsety
        return zip(x, y)
        
poly = MyPoly(xy=(1,1), numVertices=6, radius=5)

fig = figure()
ax = fig.add_subplot(111, xlim=(-100, 100), ylim=(-100, 100), autoscale_on=False)
ax.add_patch(poly)


def start(event):
    fig.canvas.mpl_disconnect(start.cid)
    randn = nx.mlab.randn
    for i in range(200):
        poly.offsetx += 2*randn()
        poly.offsety += 2*randn()
        fig.canvas.draw()
        
start.cid = fig.canvas.mpl_connect('draw_event', start)

show()

Hi Andrew,

On Fri, May 26, 2006 at 11:42:07AM -0700, Andrew Straw wrote:
> Wishing that in 2006 we as a human race could come up with a better,=20
> open video format, ...

I think most of the problems is caused by software patents.  It is
just not safe for Linux distributions etc. to integrate video
encoders, so all the solutions which exist are hidden away somewhere,
are not well integrated into the system, and also not too well tested.

By the way: does anybody know how to move a patch in matplotlib?
set_data works for lines, but what works for patches?

Many thanks,
Jochen
--=20
http://seehuhn.de/

Hi Alan,

On Fri, May 26, 2006 at 12:26:07PM -0400, Alan G Isaac wrote:
> How are you turning your PNGs into an animation?

Sorry about the slow answer.  I just used mencoder:

    mencoder 'mf://oc/*.png' -mf type=3Dpng:fps=3D12 -ovc lavc -lavcopts vc=
odec=3Dmpeg4 -o ocean.avi

All the best,
Jochen
--=20
http://seehuhn.de/

On Fri, 26 May 2006, Andrew Straw apparently wrote: 
> ffmpeg -hq -b 8000 -f mpeg2video -r 30 -i frame%03d.png movie.mpeg" 
>  * it seems very fragile -- changing the frame rate or the 
>  codec usually breaks one of the above points 

OK.  Thanks for the information and warning.

Did you experiment with MNG, or is support just not there yet?
(And will the next PIL be supporting MNG?)

Cheers,
Alan Isaac