matplotlib-users Mailing List for matplotlib

Maybe I have reinvented the wheel, but I find the attached code snippet
very useful.
I have modified a bit the recipe at
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/65222
to be used in the following situation:
You plot (interactively) something in a main program, which than works
heavily. Normally, when the figure window gets obscured, it will not
redraw. The attached code shows how to make a thread that periodically
redraws the figure.
r.

Hello,
I am using the OO interface to plot some data in logarithmic y-scale.
The data displayed are almost constant but not entirely, see the
attached image. In order to see the details, I would like to do
something like 'axis( 'image' )' for the yaxis. I have tried to play
with axes.set_ylim(), axes.yaxis.set_ticks() but failed utterly.
Can anyone help me?
For linear scaling, there is no problem - the axes limits are well
adjusted without any intervention.
thanks,
r.

This will give you a smooth line for your cumulative distribution function:
x = randn(10000)
y = sort(x)
plot(y,linspace(0,1,10000))
Mark

I have two plots.
first one is velocity data from servo controller (freq) - plant 
reciprocates back and forth so we got turn data in there as well
second one is psd (power spectral density) so we can see where we got 
resonances etc.
When we zoom in on on section of first plot (say the forward movement), 
I'd like to recalc the psd with only the data that's been zoomed in on.
Everything kind of works except for somewhere to trigger from.
I had thought of trying resize_event - however I cannot get this 
working- see other post.
I played with button_release_event to get the code basically working, 
however that event occurs before the first graph gets resized, so the 
region I am calculating the psd on is wrong, maybe because I am using
xlim = myAxis.get_xlim()
to find the limits of the first graph (which hasn't been re-drawn yet)
Is there some way I can hook the re-calc/draw of psd to the zooming of 
first graph?
Previously with 2 plot commands, I have used subplot(212, sharex=p1), to 
hook the two graphs together on the xaxis
however as the second graph is a psd I don't know how to hook the psd 
input data to the xaxis of the first graph.
Thanks
Steve

Richard Brown wrote:
> Hi there,
> 
> I'm pretty new to python; I'm in the process of switching from Matlab.
> I do quite a bit of image processing in my research, and while
> pylab/matplotlib seems to be a great plotting library, some of the
> quirks seem just a little bit frustrating - I'm hoping for some
> enlightenment :)
> 
> When I use imshow or matshow to display an array, the points with
> index (m, n) are displayed with the pixels centred at (0.5 + m, 0.5 +
> n). Is there a setting somewhere to make it so that the centres of the
> pixels are at the index values rather than their bottom left corners?
> Or must I be always adding 0.5 to things to make them appear in the
> right places?
Coincidentally, a few days ago I made this change for matshow; I had 
made it in spy some time ago. I have so far left imshow alone; isn't 
its present behavior consistent with Matlab? That is not necessarily a 
good reason for leaving it the way it is, but it is reason for some 
caution. I suspect quite a few people may prefer it the way it is; 
let's see who responds, and what opinions are voiced.
One way of maintaining compatibility (if it is indeed compatible now, 
and if this is judged desirable) would be to add a kwarg and/or rc 
option. But if there is a consensus that imshow should by default put 
index ticks at cell centers, then I will be happy to make that change.
Eric
> 
> Thanks, I appreciate any help
> 
> Richard

Hi there,
I'm pretty new to python; I'm in the process of switching from Matlab.
I do quite a bit of image processing in my research, and while
pylab/matplotlib seems to be a great plotting library, some of the
quirks seem just a little bit frustrating - I'm hoping for some
enlightenment :)
When I use imshow or matshow to display an array, the points with
index (m, n) are displayed with the pixels centred at (0.5 + m, 0.5 +
n). Is there a setting somewhere to make it so that the centres of the
pixels are at the index values rather than their bottom left corners?
Or must I be always adding 0.5 to things to make them appear in the
right places?
Thanks, I appreciate any help
Richard
-- 
Richard Brown
Ph.D. Candidate
Dept. of Mechanical Engineering
University of Canterbury, NZ

Trying to get resize event to work, but either I don't understand the 
definition of when resize_event should work, or it's broken.
for example
=======================
from matplotlib import pylab , numerix
def GotResizeEvent( event ):
 print 'Resize event detected'
def GotDrawEvent( event ):
 print 'Draw event detected'
X = range(0, 200)
Y = pylab.sin(X)
r = pylab.plot(X,Y)
pylab.connect( 'resize_event', GotResizeEvent)
pylab.connect( 'draw_event', GotDrawEvent)
pylab.show()
=========================
Will only get draw_events as I zoom in on the data, never a resize event?
I also get draw_events as I resize the window itself, but never a 
resize_event.
So my question, .. what user activity triggers a resize event?
Numerix Version: numpy 1.0
MatPlotLib Version: 0.87.7
Steve