Re: [Matplotlib-users] imlim in ax.imshow

On 2012/10/02 9:11 AM, Damon McDougall wrote:
> On Tue, Oct 2, 2012 at 8:07 PM, K.-Michael Aye <kmi...@gm...> wrote:
>>
>> On Oct 2, 2012, at 12:06 PM, Damon McDougall <dam...@gm...> wrote:
>>
>>> On Tue, Oct 2, 2012 at 8:00 PM, K.-Michael Aye <kmi...@gm...> wrote:
>>>>
>>>> On Oct 2, 2012, at 11:09 AM, Damon McDougall <dam...@gm...> wrote:
>>>>
>>>>> On Tue, Oct 2, 2012 at 5:51 PM, K.-Michael Aye <kmi...@gm...> wrote:
>>>>>>
>>>>>>
>>>>>> On Oct 2, 2012, at 6:33 AM, Damon McDougall <dam...@gm...> wrote:
>>>>>>
>>>>>>> On Tue, Oct 2, 2012 at 2:19 PM, Benjamin Root <ben...@ou...> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> On Mon, Oct 1, 2012 at 7:20 PM, Michael Aye <kmi...@gm...> wrote:
>>>>>>>>>
>>>>>>>>> Hi!
>>>>>>>>>
>>>>>>>>> I see that the function ax.imshow takes the parameter 'imlim' but in
>>>>>>>>> the source (status: EPD 7.3-2) it is not being used?
>>>>>>>>> So what is it for?
>>>>>>>>>
>>>>>>>>> Best regards,
>>>>>>>>> Michael
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>> Confirmed.  I don't see imlim anywhere except in the imshow() signature.  I
>>>>>>>> have no recollection of this parameter, so it might be from before my time.
>>>>>>>>
>>>>>>>> Ben Root
>>>>>>>
>>>>>>> Is there some functionality you were looking for or were you just
>>>>>>> exploring the codebase?
>>>>>>>
>>>>>> How nice of you to ask! ;)
>>>>>> Indeed: I had the case that image arrays inside an ImageGrid where shown with some white overhead area around, e.g. for an image of 100 pixels on the x-axis, the imshow resulted in an x-axis that went from -10 to 110. I was looking for a simple way to suppress that behavior and let imshow instead use the exact image extent. I believe that the plot command has such a flag, hasn't it? (I.e. to use the exact xdata range and not try to beautify the plot?
>>>>>>
>>>>>> Michael
>>>>>>
>>>>>>
>>>>>>> --
>>>>>>> Damon McDougall
>>>>>>> http://www.damon-is-a-geek.com
>>>>>>> B2.39
>>>>>>> Mathematics Institute
>>>>>>> University of Warwick
>>>>>>> Coventry
>>>>>>> West Midlands
>>>>>>> CV4 7AL
>>>>>>> United Kingdom
>>>>>
>>>>> Is the 'extent' keyword what you're looking for?
>>>>>
>>>>
>>>> No, because it needs detail. I was looking for a boolean switch that basically says: Respect the data, not beauty.
>>>
>>> I don't understand what you mean by 'beauty'. If your image is 100
>>> pixels wide and 50 pixels tall, what is it about extent=[0,100,0,50]
>>> that doesn't do what you want?
>>>
>> As I wrote, that's not what is happening. I get extent=[-10,110,0,50].
>>
>>
>>> --
>>> Damon McDougall
>>> http://www.damon-is-a-geek.com
>>> B2.39
>>> Mathematics Institute
>>> University of Warwick
>>> Coventry
>>> West Midlands
>>> CV4 7AL
>>> United Kingdom
>>
>
> The following script works for me:
>
> import numpy as np
> import matplotlib.pyplot as plt
>
> image = np.random.random((100,50))
>
> fig = plt.figure()
> ax = fig.add_subplot(1, 1, 1)
> ax.imshow(image, extent=[0,100,0,50])
> plt.show()
>
>

I think the problem is that Michael is using ImageGrid, and apparently 
it is not using the tight autoscaling that imshow normally uses by default.

Eric