[SciPy-user] plt.image: zoom too far?

eric jones eric at enthought.com
Wed Aug 7 11:53:09 CDT 2002


Hey Bryan,

The entire code base for plt is in python, so hopefully it will be easy
for you to patch this in.

Thanks,
eric

> -----Original Message-----
> From: scipy-user-admin at scipy.net [mailto:scipy-user-admin at scipy.net]
On
> Behalf Of bryan cole
> Sent: Wednesday, August 07, 2002 4:15 AM
> To: scipy-user at scipy.net
> Subject: RE: [SciPy-user] plt.image: zoom too far?
> 
> This should not be too hard to fix.
> 
> I have implemented image zooming on another wxPython plot widget: The
> original is stored as a wxImage. When zooming, I take a sub-image
using
> the wxImage.GetSubImage() method then rescale the sub-image back up
the
> the desired size using wxImage.Rescale().
> 
> I've attached the python file (wxLabPlot.py) if anyone wants to look.
> It's a crude adaption of the wxPlotCanvas that comes with wxPython.
> Lines 186->212 deal with the image scaling.
> 
> If the plt module is written in Python, I could probably write a patch
> but it will take me a week or two to get round to it.
> 
> Bryan
> 
> On Tue, 2002-08-06 at 22:56, eric jones wrote:
> > Yep, this is a known bug.  The zooming feature relies on wxPython to
> > zoom the image, and it looks like wxPython generates the entire
image
> > when scaling it resulting in a memory explosion.  This needs
> > reimplementation to solve the problem for images.  It doesn't affect
> > scatter plots -- just images.
> >
> > A patch would be very welcomed. :-)
> >
> > Eric
> >
> >
> > > -----Original Message-----
> > > From: scipy-user-admin at scipy.net
[mailto:scipy-user-admin at scipy.net]
> > On
> > > Behalf Of Adam C. Finnefrock
> > > Sent: Tuesday, August 06, 2002 4:22 PM
> > > To: scipy-user
> > > Subject: [SciPy-user] plt.image: zoom too far?
> > >
> > > Hi all,
> > >
> > > Has anyone had trouble using plt.image and zooming in too far?
> > >
> > > The symptoms are either using all available memory (Linux, >
400MB)
> > > or showing a blank white window (Linux, Windows).
> > >
> > > Example:
> > >
> > > >>> import gui_thread
> > > >>> <Importing wxPython...  done.>
> > > >>> from scipy import *
> > >
> > > >>> from scipy import plt
> > > >>> img = plt.lena()
> > > >>> plt.image(img)
> > >
> > > 1.  Use the mouse, zoom in on the eye near the center of the
image.
> > >     (In linux, python's memory usage peaks and then returns to
> > original
> > > value.)
> > > 2.  Now, zoom in closer using the mouse so that just the iris and
> > pupil
> > > would
> > >     be shown.  (In linux, memory usage rises to > 400MB and this
disk
> > > starts
> > >     swapping.  In Windows, the image is not rendered but instead a
> > white
> > >     canvas is shown.)
> > >
> > > Same results can be obtained on the command-line:
> > > >>> z=plt.image(img)
> > > >>> z.x_axis.bounds = [245,250]
> > > >>> z.y_axis.bounds = [245,250]
> > > >>> z.update()
> > >
> > > Is this a known bug?  Should I be posting to scipy-devel instead?
> > >
> > >
> > > Thanks,
> > > Adam
> > > _______________________________________________
> > > SciPy-user mailing list
> > > SciPy-user at scipy.net
> > > http://www.scipy.net/mailman/listinfo/scipy-user
> >
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