Hi there
I have a function where I want to display an image, get the user to
zoom in on a region of interest, and then return the axes limits.
But the problem is, I can only use it once, the second time it gets
called in a script the figure doesn't appear. I know this is to do
with show() not being supposed to be used multiple times, but I don't
know what I should be doing instead ... any tips? (I'm still new to
python btw)
Also, if there's a better (more pythonic way) to do what I'm doing, I
would appreciate your input. I'm not sure if what I'm doing with the
region variable is dodgy or not.
Currently, I'm doing this:
from pylab import *
def getroi(im):
imshow(im)
title('Zoom in to region of interest, then press a key')
region = array([0, 0, 0, 0]) # Placeholder values
def keypressed(event):
region[:] = [round(i) for i in gca().axis()]
close(gcf())
# Connect keypressed to event handler
connect('key_press_event', keypressed)
show()
return region
thanks,
Richard
--
Richard Brown
Ph.D. Candidate
Dept. of Mechanical Engineering
University of Canterbury, NZ
Not sure what region[:] is supposed to achieve. You are creating a copy
with the same name, so you are over-riding the original variable.
Hi there
I have a function where I want to display an image, get the user to
zoom in on a region of interest, and then return the axes limits.
But the problem is, I can only use it once, the second time it gets
called in a script the figure doesn't appear. I know this is to do
with show() not being supposed to be used multiple times, but I don't
know what I should be doing instead ... any tips? (I'm still new to
python btw)
Also, if there's a better (more pythonic way) to do what I'm doing, I
would appreciate your input. I'm not sure if what I'm doing with the
region variable is dodgy or not.
Currently, I'm doing this:
from pylab import *
def getroi(im):
imshow(im)
title('Zoom in to region of interest, then press a key')
region = array([0, 0, 0, 0]) # Placeholder values
def keypressed(event):
region[:] = [round(i) for i in gca().axis()]
close(gcf())
# Connect keypressed to event handler
connect('key_press_event', keypressed)
show()
return region
thanks,
Richard
--
Richard Brown
Ph.D. Candidate
Dept. of Mechanical Engineering
University of Canterbury, NZ
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On 30/03/07, bre...@un...
<bre...@un...> wrote:
>
> Not sure what region[:] is supposed to achieve. You are creating a copy
> with the same name, so you are over-riding the original variable.
>
That doesn't seem to be the case - it returns the right thing on the
first call - i.e. region got changed, but on subsequent calls the
figure is displayed and the function returns array([0,0,0,0]). I
thought taking the slice just gave access to the internals of region
...
How does one assign a new value to a variable in a containing scope?
Richard
>
> Hi there
>
> I have a function where I want to display an image, get the user to
> zoom in on a region of interest, and then return the axes limits.
>
> But the problem is, I can only use it once, the second time it gets
> called in a script the figure doesn't appear. I know this is to do
> with show() not being supposed to be used multiple times, but I don't
> know what I should be doing instead ... any tips? (I'm still new to
> python btw)
>
> Also, if there's a better (more pythonic way) to do what I'm doing, I
> would appreciate your input. I'm not sure if what I'm doing with the
> region variable is dodgy or not.
>
> Currently, I'm doing this:
>
> from pylab import *
>
> def getroi(im):
> imshow(im)
> title('Zoom in to region of interest, then press a key')
> region = array([0, 0, 0, 0]) # Placeholder values
>
> def keypressed(event):
> region[:] = [round(i) for i in gca().axis()]
> close(gcf())
>
> # Connect keypressed to event handler
> connect('key_press_event', keypressed)
>
> show()
> return region
>
>
>
> thanks,
>
> Richard
On 3/30/07, Richard Brown <rg...@gm...> wrote: > On 30/03/07, bre...@un... > <bre...@un...> wrote: > > > > Not sure what region[:] is supposed to achieve. You are creating a copy > > with the same name, so you are over-riding the original variable. > > > > That doesn't seem to be the case - it returns the right thing on the > first call - i.e. region got changed, but on subsequent calls the > figure is displayed and the function returns array([0,0,0,0]). I > thought taking the slice just gave access to the internals of region > ... > > How does one assign a new value to a variable in a containing scope? You can declare the "region" variable as global in keypressed(): def keypressed(event): global region region = ... and "region" does not need to get initialized in the containing scope. Cheers, ~ Antonio