saving edited colormap data

After editing an existing colormap with the colormapeditor, I want to save it. The documentation states that I should do something like:

mycmap = get(fig,'Colormap');

However, the saved colormap, mycmap, has the original colormap data not the eddited one. Here's a minimal example:

imagesc(peaks(10));
colormap(hot(6))

Now go into the figure's gui colormap editor using >Edit>Colormap and only change yellow to blue. Now after that press Apply see that indeed the figure has changed. Now write on the command line:

mycmap = get(gcf,'Colormap')

 mycmap =

    0.5000         0         0
    1.0000         0         0
    1.0000    0.5000         0
    1.0000    1.0000         0
    1.0000    1.0000    0.5000
    1.0000    1.0000    1.0000

there no "blue" ([0 0 1]) color. Interestingly, when the figure is saved the colormap is saved with it, but for some reason I cant access the edited colormap. What am I doing wrong? (I'm using Matlab 2014b)

Answer 1

[Adi Natan]

It looks like the colormap is now associated with the axes rather than the figure. So,

cmap = colormap(gca);

will retrieve the edited map.

[Walter Roberson]

So I provided the correct solution but don't even get a vote? :(

[Adi Natan]

saying "So use gca" is a very partial answer. I had to go and investigate how one should use gca, and that was far from the regular way gca is usually used (i.e. set(gca...) ). that is why I felt I had to write the full answer.

[Zhao-Yang CHAI]

Very useful! I have met the same problem and maybe it's a bug. It's strange that the colormaps of gca and gcf are different.

Answer 2

[Walter Roberson]

Starting in R2014b, colormaps are per-axes rather than per-figure. So use gca (or some other way of identifying the axes) instead of gcf .

[hamed amini]

mycbar= get(gca,Colormap'); % this works

set(gcf,'Colormap',mycbar); %this works

set(gca) does not work in R2017a. This does not sound right and is confusing.

[Walter Roberson]

?

set(gca, 'Colormap', mycbar)

works

Answer 3

[Sean de Wolski]

Is gcf, the same as fig?

[Adi Natan]

the input of get command assumes there is an object to get. fig is just a name you can give a figure object. When a figure is open the gcf (get current figure) is that object. If you try just get(fig...) you'll get an error. Also, why are you using the answer to give a comment? You sis answer the question, you just had a comment.

[Sean de Wolski]

No, my question will possibly point you to what's wrong. gcf is the current figure which may not be the same as the figure you modified :)

[Sean de Wolski]

However, I am able to reproduce this behavior. I would've expected either the Colormap or the CDataMapping of the Image to have changed by using the colorbareditor but you're right it doesn't appear to be changing anything.

[Adi Natan]

well, that's not surprising. I just hope other people would still look at this question, even though there seems to be an "answer" though it is still not answered.

[Ken]

I have the same problem! This is a bug that needs fixing, or a good explaination

[Adi Natan]

I found the answer, see below...