[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Colour scaling in imshow
From: |
John W. Eaton |
Subject: |
Re: Colour scaling in imshow |
Date: |
Mon, 17 Jan 2011 14:58:43 -0500 |
On 17-Jan-2011, Jordi Gutiérrez Hermoso wrote:
| 2011/1/16 John W. Eaton <address@hidden>:
| > On 16-Jan-2011, Jordi Gutiérrez Hermoso wrote:
| >
| > | There's currently a bug in imshow where
| > |
| > | x =rand(100:
| > | imshow(x);
| > | figure;
| > | imshow(x,[0,255]);
| > |
| > | produces two identical images, whereas the second one should be almost
| > | black. Attached is a patch that seems to fix this. I'm not sure this
| > | is the right fix, so I won't push it right away. Notice that I also
| > | had to ensure that display_range was a double despite the warnings in
| > | the code that it was wrong to do. Without it, the scaling operations
| > | that use display_range were not working properly, due to the vagaries
| > | of integer division.
| > |
| > | I'm not completely sure the attached patch is the correct one, so I'll
| > | wait for review before pushing it.
| >
| > Does Matlab set clim to [0, 1] for this case? If not, then this is
| > not the right fix.
|
| Asking around in the ##matlab channel in IRC, it appears that imshow
| does indeed set the clim property of the parent axes object to [0,1].
| A fun side effect of that conversation is that apparently imshow
| should return a handle to the image, not to the parent axis object,
| like our current imshow implementation does. I saw that imshow should
| also accept property-value pairs to set any of its properties.
|
| Can someone with Matlab access please confirm?
>> version
ans =
7.10.0.499 (R2010a)
>> x = rand (100);
>> h = imshow (x);
>> get (h, 'type')
ans =
image
>> image_clim = get (h, 'clim')
image_clim =
on
>> axes_clim = get (gca, 'clim')
axes_clim =
0 1
>> figure
>> h = imshow (x, [0, 255]);
>> get (h, 'type')
ans =
image
>> image_clim = get (h, 'clim')
image_clim =
on
>> axes_clim = get (gca, 'clim')
axes_clim =
0 255
jwe
- Colour scaling in imshow, Jordi Gutiérrez Hermoso, 2011/01/16
- Colour scaling in imshow, John W. Eaton, 2011/01/16
- Re: Colour scaling in imshow, Jordi Gutiérrez Hermoso, 2011/01/17
- Re: Colour scaling in imshow,
John W. Eaton <=
- Re: Colour scaling in imshow, Jordi Gutiérrez Hermoso, 2011/01/20
- Re: Colour scaling in imshow, Jordi Gutiérrez Hermoso, 2011/01/20
- Re: Colour scaling in imshow, Søren Hauberg, 2011/01/20
- Re: Colour scaling in imshow, John W. Eaton, 2011/01/20
- Re: Colour scaling in imshow, Jordi Gutiérrez Hermoso, 2011/01/21
- Re: Colour scaling in imshow, John W. Eaton, 2011/01/21