freezeColors / unfreezeColors

Use multiple colormaps per figure! Version 2, now works for many types of objects, not only images.

Description

Version 2.3, 3/2007 (*NEW: 7/2009, Colorbar workaround is below)

Problem: There is only one colormap per figure, so all plots share the same colormap. Often one wants different colormaps.

Solution: This function pair provides an easy way to have plots using different colomaps in the same figure.

Example:
subplot(2,1,1)
imagesc(X)
colormap hot
freezeColors

subplot(2,1,2)
surf(Y)
colormap hsv
etc...

Note, you can also pass an axis handle to freezeColors. This is useful if you'd like to freeze the colors of a colorbar:

**** COLORBAR WORKAROUND ****
** Note: in recent versions of MATLAB, you must substitute
** colorbar('v6') for colorbar in the following examples
** To suppress the warning messages:
** warning('off','MATLAB:colorbar:DeprecatedV6Argument')
** you may put this command in 'startup.m' to run every time

h=colorbar;
freezeColors(h), or simply:

freezeColors(colorbar)

FUNCTIONS

freezeColors Freeze colors of plots, making them immune to later changes in the colormap. Converts colors of many graphics objects (images, surfaces, scattergroups, bar plots, patches, etc--anything using indexed CData) to [r g b] truecolor.

unfreezeColors Reverses the effects of freezeColors. Restores the original indexed color data, allowing the colormap and caxis to again affect the plots.

Demo & Documentation in freezeColors_pub.html

• Acknowledgements: This submission has inspired the following:; Shaded pseudo color, imagescnan.m v2.1 (Aug 2009), COLORMAP and COLORBAR utilities (Sep 2009)
• MATLAB release: MATLAB 7.4 (R2007a)
• Other requirements: Tested under: 7.0.1, 7.3, 7.4, 2009a Newer versions must use >> colorbar('v6') to work properly
• Published M Files: Demonstration of freezeColors / unfreezeColors

Other Files

__MACOSX/freezeColors/._.DS_Store,
__MACOSX/freezeColors/._Contents.m,
__MACOSX/freezeColors/._freezeColors.m,
__MACOSX/freezeColors/._unfreezeColors.m,
__MACOSX/freezeColors/demo/._.DS_Store,
__MACOSX/freezeColors/demo/html/._freezeColors_pub.png,
__MACOSX/freezeColors/test/._.DS_Store,
__MACOSX/freezeColors/test/._test_main.m,
freezeColors/.DS_Store,
freezeColors/Contents.m,
freezeColors/demo/.DS_Store,
freezeColors/demo/html/freezeColors_pub.png,
freezeColors/demo/html/freezeColors_pub_01.png,
freezeColors/demo/html/freezeColors_pub_02.png,
freezeColors/freezeColors.m,
freezeColors/test/.DS_Store,
freezeColors/test/test_main.m,
freezeColors/unfreezeColors.m,
license.txt

[PB ']

Well done! This is absolutely one of my all time favourites in the file exchange. /PB

[Anil Seth]

What a fine file this is.

[Anita D]

really great, thank you so much, you saved my gui! now if i could only freeze the colorbars...

[Anita D]

ahh, it freezes the colorbars too! took me forever to figure out, but is awesome!

[A. Brunner]

What a nice tool. I was about to start writing my own little program, but why re-inventing the wheel?

Thank you for saving me time and nerves!

[O Yamashita]

This is a very nice tool!!
BTW, there may be a bug on line59,
  idx = ceil( (cdata - cax(1)) / (cax(2)-cax(1)) * nColors);

when 'cdata' is of type "uint", many entries of (cdata - cax(1)) / (cax(2)-cax(1)) could be zeros. This can be avoid by changing to

idx = ceil( (cdata - cax(1))*nColors / (cax(2)-cax(1)));

Hope this helps.

[John Iversen]

From the author:
A change was made to allow freezeColors to work with scaled, integer images.

Thanks to O. Yamashita for suggesting this.

The new version will appear in a few days (once reviewed by the Mathworks). In the meantime, the corrected line reads:
 idx = ceil( (double(cdata) - cax(1)) / (cax(2)-cax(1)) * nColors);

Thank you for the interest.

[Mike L]

It's just what I need and does the job very nicely. Excellent script.

[Darren M]

Was bashing my head off the wall trying to get a grayscale image to be beside a hot and 2 personalized colormaps for a publication. Thanks much!

[John Iversen]

Note from author:
A second, updated version (2.1) uploaded 9/5/06. I realized v2 didn't freeze colors of bar plots, so that was added. Comments welcome.

[J Roering]

simple, easy, works perfectly, THANKS for saving from the "CLim" script offered with the matlab help section.

[p p]

Is there a version for matlab R13 ?

[Samuel Tucker]

very sweet... also appears to work for R13.

[M C]

Very good, useful function. Thanks.

[Anne Marie treguier]

 

[Gleb Tcheslavski]

very handi! Thank's!

[Andrew Stevens]

It is a good attempt at patching a fundamental problem in ML.

However, when I try to use it with a colorbar, the function resets the scale of the colorbar to go between 0 and 1. The same thing appears to happen in the author's demo.

Does anyone know how to get around this problem? I tried first freezing the colorbar and then the axis and vice-versa (without luck).

[John Iversen]

Hi,

Thanks for the comment. My apologies. I noticed this problem as well, and it has been fixed. However, the newest version is not up yet. Please check back in a few days. In the meantime, I'm happy to email the newer version to you.

John Iversen

[Chris K]

A really great tool, but I am having a problem where the colormap of the colorbar of the first subplot is reset to the colormap of the second subplot. Any suggestions?

[Chris K]

Oops, apologies! I just noticed the freezeColors(colorbar) option. Now I'm satisfied!

[Yongmin Jiang]

Another side effect is the text of the figure is going to bitmap as well(does't look good), and when you save the figure in .eps, .jpg or other format, the picture quality is not as good, and the size of the figure is big.

[John Iversen]

Yongmin, Unfortunately, those issues sound like general issues with Matlab graphics, not freezeColors. I have not encountered such problems, but if you have an example, I can look at it to see if there is a workaround. However, you may have better luck contacting Mathworks support directly.

[Frank Bahr]

This is exactly what I was looking for. Thank you, guys!

[Damien G]

I can now superimpose a color pseudocolor plot on another one containing a gray-scale colormap. It works, it's great. Many thanks.

[Ryan Van Fleet]

The perfect fix to my problem my multi-color-mapping problem. Very Handy. I had to comment two lines out of the freeze file that produced errors. After that worked great.

[Jiank L]

thanks, great. but it seems that it can not work with `set' command, only work with 'imagesc', etc. so when plotting pic. in a for loop, we have to use multiple 'plot', but not 'set'. Maybe one can add a handle in freezeColors? :

      %set(im3,'CData',cee1);
      imagesc(cee1);
      colormap(hot);
      freezeColors;
      freezeColors(colorbar);

[Bram van Hoof]

Seems like an excellent way to solve this exact same problem that i have had!

[Leo B]

Great job!
Works great for plotting different plots and colormaps with hold on in the same figure and axes.

[Eduardo Gonzalez]

Excellent, but it did not work on colorbars in Matlab R2007b

[Irian O]

Excellent work!

[Carlos Adrian Vargas Aguilera]

Excellent function John. I just submited a function that frozen the colorbar map too for MATLAB 2007B, you should check it out: IMAGESCNAN

Carlos

[Ting-Chieh Lin]

This code is very useful. However, it seems works only for the colormap. The colorbar cannot work in Matlab 2008a.

[Frank Leone]

Thanks a lot, does exactly what I wanted. An additional feature, obvious but not mentioned, that it is also usable to use multiple colormaps within one set of axes using. For example:

plot (...)
colormap (...)
freezeColors
hold on;
plot (...)
colormap (...)

It is rather slow though for big plots, but that isn't a real problem.

[David Lei]

unfortunatly I got an errormessage after executing the demoprogram. I have got Matlab 6.5. Is this the problem?

-------------------------------------------
subplot(2,1,1); imagesc(peaks); colormap hot; freezeColors

subplot(2,1,2); imagesc(peaks); colormap jet; freezeColors

??? Error using ==> nargchk
Too many input arguments.

Error in ==> D:\MATLAB6p5\work\freezeColors.m (checkArgs)
On line 206 ==> error(nargchk(0,3,nargs,'struct'))

Error in ==> D:\MATLAB6p5\work\freezeColors.m
On line 75 ==> [h, nancolor] = checkArgs(varargin);

[MARSSET Bruno]

We had to drape P wave velocities values over seismic amplitudes, therefore we needed two different colormaps.
Playing arount with freezeColors and Transparency did the trick !
Many thatks
Bruno MARSSET

[Jody Klymak]

Yes I can't figure out how to make 2008a/b colorbars freeze either.

[Jody Klymak]

To follow up: colorbar.m appears to redraw the image when the colormap is updated. There is a callback to "FigureChangedColor" that erases the old image and makes a new one. So the cdata that was set in the old colorbar is erased and replaced when colormap is called. Not sure how to get around it.

[Liam Harrington-Missin]

Like Jody I have been having issues with the colorbar. I can't seem to get them to stick to selected colormaps, I'm using R2007b

[Liam Harrington-Missin]

To follow up: The problem is when you change the colormap and not easily solved in the freezeColors / unfreezeColors. I have created a simple fixme to get round it which I can provide if anyone needs it.

[Anthony Lamb]

Very good tool John. Unfortunately when used to have two color maps and colorbars on the same plot is seems to change my surface plot colors to those that match the OpenGL renderer.. The colorbars are ok it's just that little hick up... Any suggestions on a fix????
Oh.. Liam I'd like to get my hands on your quick fix as well..

[Sebastian Thiele]

Excellent Work!

[Arnaud Laurent]

Thanks, you solved my problem! Nice work.

[Alessio Rucci]

Hi, I'm trying to plot in the same figure (not in different subplot of thesame image) two different data with different colorbar, but if I use freezeColor it doesen't work....

[X,Y]=meshgrid(-10:10,-20:20);
Z1=sqrt((X/10).^2+(Y/10).^2)+2;
Z2=sqrt((X/10).^2+(Y/10).^2)-2;

figure,contour3(X,Y,Z1); axis xy; colormap hsv;
freezeColors; freezeColors(colorbar);
hold on;contour3(X,Y,Z2); axis xy; colormap jet;
freezeColors; freezeColors(colorbar);

is it possible to have both the colorbars, one for each data?

Thaks

[Jochen Deibele]

Had some problems with two axes, one image in each with a colormap with 255 entries. Using freezeColors a wrong color number is detected which results in distorted images.

adding a (h) behind colormap in line 81 and caxis in line 83 solves this, so that the lines look like:
81: cmap = colormap(h);
83: cax = caxis(h);

Nevertheless: Excellent work!
This fixes a Matlab flaw (colormap should be an image or axes property).

[Daniel Golden]

Great little tool, that doesn't work on colorbars in the latest version of Matlab.

Liam, it would be great if you could post your quick fix!

[Emanuele Ruffaldi]

 

[John Iversen]

Hi,

** WORKAROUND FOR PROBLEMS WITH COLORBARS **

I'm really sorry not to respond earlier--I had no idea about the recent posts!

There is a workaround for the problem with freezing colorbars:

     freezeColors(colorbar('v6'))

It works for me as of 2009a, so I expect it will work for other earlier versions.

To silence the warning messages,
 
    warning('off','MATLAB:colorbar:DeprecatedV6Argument')

should be run (once per session--put it in 'startup.m')

I hope this helps. Please let me know if not.

Best regards,

John

[Nazatul Naquiah Ahba]

cool! helps to solve my problem! :D

[Daniel Armyr]

Neat program, but I found a bug:
Running the following line:
>>image; freezeColors

gives the following error message:
??? Subscript indices must either be real positive integers or logicals.

Error in ==> freezeColors at 136
        c = cmap(idx,i);

Placing a breakpoint and looking at idx on the line in question reveals that idx consists of floating point numbers and not integers at that point.

Unfortunately, I do not have enough of an understanding of the program to present a fix.

[Pearl]

 

[David]

Hello

I using the freezing colorbars with 'v6' as you said. But this way I cannot define the location of the colorbar. Is there any simple solution for it. If I use

hc = colorbar('location',...)
freezeColors(hc)

it doesn't work anymore as 'v6' is missing...

Any ideas?

Thanks a lot,

David

[Ian Howat]

Great work!

[John Iversen]

Fix for error pointed out by Daniel Armyr (11Aug): "image; freezeColors"

after the line: idx = cdata;
>insert the line: idx = floor(idx);

This will take care of the problem. Thanks for pointing it out.

[David]

Hi everybody!

For people having problem with the fixing of the colorbar (not only the colormap) I suggest you the combination with cbfreeze:

colorbar('location','SouthOutside');
freezeColors;
cbfreeze

which worked fine for me!

David.