Re: [Matplotlib-users] dynamic colorbar

[Rodrigo C. <rc...@ge...>]

Ok, here's the problem, illlustrated by a simple variant of the 
dynamic_image_gtkagg.py example (see below).
I've put in a colorbar and I'm letting the amplitude of the pattern 
grow linearly in time. The result is that the colormap limits remained 
fixed at their initial values (-2,2), rather than change in time. If I 
don't put in the colorbar, the colormap limits *do* change. I'm a bit 
confused about all this.
I tried changing the normalization of the colormap doing 
im.autoscale(z) each time z is updated, but that doesn't work ...

Rodrigo

-----------

#!/usr/bin/env python
"""
An animated image
"""
import sys, time, os, gc
from matplotlib import rcParams

from matplotlib.matlab import *
import gtk

x = arange(120.0)*2*pi/120.0
x = resize(x, (100,120))
y = arange(100.0)*2*pi/100.0
y = resize(y, (120,100))
y = transpose(y)
z = sin(x) + cos(y)
im = imshow( z, cmap=cm.jet)#, interpolation='nearest')

colorbar()

manager = get_current_fig_manager()

cnt = 0
tstart = time.time()
def updatefig(*args):
     global x, y, cnt, start
     x += pi/15
     y += pi/20
     z = ( sin(x) + cos(y) ) * cnt/5.
     im.set_array(z)
     manager.canvas.draw()
     cnt += 1
     if cnt==50:
         print 'FPS', cnt/(time.time() - tstart)
         return gtk.FALSE
     return True


cnt = 0

gtk.idle_add(updatefig)
show()

-----------------------------

On Monday, September 13, 2004, at 03:47  PM, John Hunter wrote:

>>>>>> "Rodrigo" == Rodrigo Caballero <rc...@ge...> writes:
>
>     Rodrigo> One of my favorite aspects of matplotlib is how easy it
>     Rodrigo> is to make dynamic plots. When doing this with 2D
>     Rodrigo> renderings using pcolor or imshow, is there an easy way
>     Rodrigo> to also dynamically update the colorbar?
>
> It should *just work*.  images (matplotlib.image.AxesImage) and
> pcolors (matplotlib.collections.PolygonCollection) both derive from
> matplotlib.cm.ScalarMappable.  This class implements an observer
> pattern, and the colorbar registers itself with the ScalarMappable
> instance.  If you change the normalization, or colormap, or
> colorlimits, the ScalarMappable instance notifies it's observers, who
> update automagically.
>
> Let me know if you run into any troubles.
>
> JDH
>
>
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