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CubeHelix Colormap Generator: Beautiful and Versatile!

version 2.2.0 (16.5 KB) by Stephen Cobeldick
The most versatile colormap generator ever! Generate colormaps suitable for grayscale conversion.

21 Downloads

Updated 26 Jul 2020

GitHub view license on GitHub

CUBEHELIX is the only colormap-generator you will ever need for MATLAB: CUBEHELIX generates colormaps for published or distributed documents as they are very attractive in full color and yet are suitable for grayscale conversion.

CUBEHELIX creates different colormaps using just a few parameters. The standard algorithm offer very attractive colorschemes for online and electronic documents (e.g. PDF), and yet when printed in grayscale they keep exactly the sequence information of the original data. CUBEHELIX function also includes two extra controls over the range and domain of the colormap values, giving a practically unlimited number of colormaps with many different styles: maximally distinct, multi or single hue, and may be suitable for grayscale printing or even simple grayscale.

### Algorithm ###

CUBEHELIX colorschemes consist of nodes along a tapered helix in the RGB color cube, with a continuous increase in perceived intensity (e.g. black->white). Thus the scheme defines attractive colormaps with a huge choice of hue, saturation and brightness, and yet printing a figure (or image) in Black-and-White (e.g. postscript) results in a monotonically increasing grayscale that retains the brightness order of the original colormap. The sequence information of the colormap is retained even in grayscale, which means an attractive colored image can be printed in grayscale and still be informative to the end-user.

The CUBEHELIX algorithm is defined here: http://astron-soc.in/bulletin/11June/289392011.pdf

For more information and examples: http://www.mrao.cam.ac.uk/~dag/CUBEHELIX/

### Examples ###

% New colors for the COLORMAP example:
S = load('spine');
image(S.X)
colormap(cubehelix) % default parameters

% New colors for the SURF example:
[X,Y,Z] = peaks(30);
surfc(X,Y,Z)
colormap(cubehelix([],0.5,-1.5,1,1,[0.29,0.92]))
axis([-3,3,-3,3,-10,5])

### Bonus Function ###

CUBEHELIX_VIEW creates an interactive figure that allows selection of the colorscheme, and that contains two colorbars showing colors of the colormap and the grayscale equivalent.

R2014b or later: CUBEHELIX_VIEW can also update other axes' or figures' colormaps in real time, for example:

S = load('spine');
image(S.X)
cubehelix_view(gca)

### Notes ###

* The original specification (the links above) misnamed the saturation option as "hue". In the CUBEHELIX function the saturation option is named "satn".

Cite As

Stephen Cobeldick (2020). CubeHelix Colormap Generator: Beautiful and Versatile! (https://github.com/DrosteEffect/CubeHelix), GitHub. Retrieved .

Comments and Ratings (10)

Tim

Fantastic color map generator. I use this all the time.

Cyril GADAL

Martin Ward

E. Cheynet

Stephen Cobeldick

@rockthekasbah: You would need to generate two colormaps, and concatenate them vertically, something like this:

map1 = cubehelix(10,2,2,1,1);
map2 = cubehelix(10,1,0,1,1);
map = [map1;map2(end:-1:1,:)];

I spent quite some time investigating this concept myself, with the intention of writing a wrapper function that returns a diverging colormap constructed from two cubehelix maps. However the huge number of input parameters (up to eight values for each cubehelix map) made it a users nightmare. Determining the color of the midpoint is not a simple task: should it be automatically determined? If so, how? What happens if the user defines two maps with very different colors at the join: what would the mid-point color be? Should the function force the user to make the adjacent colors match?

In the end I decided that because concatenating two colormaps is trivially easy, it was not worth the complexity of its own function.

rockthekasbah

How do I create a diverging colormap out of this? I played around with different settings but it is taking forever to find one. Is there an easier way?

Harry Dymond

Matthias

Excellent function. Works well, creates nice colours that do not trick the reader and prints well in gray scales. It does what it is supposed to do.

Warwick

John

Updates

2.2.0

* Add error IDs.
* Improve input checking.

2.1.0.1

* Simplfiy CUBEHELIX_VIEW figure creation.

2.1.0.0

* Update FEX blurb.

2.1.0.0

* Replace that awful automatically-generated title with the original title.

2.0.0.0

* Move to GitHub repository.
Changes to "cubehelix_view":
* Simplify internal graphics-handle management.
* Simplify figure layout.

1.8.0.0

* Minor edit to blurb, consistent parameter names.

1.7.0.0

* Use correct color terminology: rename "hue" -> "sat", and "start" -> "hue".

1.6.0.0

* Change input name from <rng> to <yrange> to avoid conflict with inbuilt function.
* Simplify input checking.
* Simplify internal passing of variables to local functions.

1.5.0.0

* Include Domain option.
* Include 3D RGB-cube viewer.
* More robust parameter finder.

1.4.0.0

- Improve input argument checking.

1.3.0.0

- Improve input argument checking.
- Viewer figure now displays warnings for clipped RGB or non-monotonic grayscale values.
- Demo now also varies the range values.

1.2.0.0

- Allow parameters to be input as a vector.
- Improve viewer background.
- Better demonstration-mode: random examples in the viewer.

1.1.0.0

- Add range sliders to viewer.
- Slightly robuster finder algorithm.
- Show some nice examples in the illustration!

MATLAB Release Compatibility
Created with R2010b
Compatible with any release
Platform Compatibility
Windows macOS Linux