createcolormap

This function allows to create colormap Nx3 array (RGB) with an arbitrary combination of colors.

createcolormap.m

This function allows to create colormap Nx3 array (RGB) with an arbitrary combination of colors. RGB values between the specified colors will be smoothly connected by linear interpolation.

Example

cmap = createcolormap(C);
cmap = createcolormap(n,C);
cmap = createcolormap(colorA, colorB);
cmap = createcolormap(n, colorA, colorB);
cmap = createcolormap(colorA, colorB, colorC, colorD, ...);
cmap = createcolormap(n, colorA, colorB, colorC, colorD, ...);

where n is the number of segments for the output color scheme, and C is the RGB matrix of color junctions.

Usage

• blue-white-red (polar)

  b = [0,0,1];
  w = [1,1,1];
  r = [1,0,0];
  
  bwr = createcolormap(b,w,r); % 256x3 array
  
  colormap(bwr)
  colorbar

  If you want to use dark blue and red colors, try below:

  b = [0.0,0.0,0.5];
  w = [1.0,1.0,1.0];
  r = [0.5,0.0,0.0];
  
  bwr = createcolormap(b,w,r); % 256x3 array
  
  colormap(bwr)
  colorbar

  To create a more discrete color structure, input the number of elements in the first argument as shown below.

  bwr = createcolormap(16,b,w,r); % 16x3 array 

• more complicated combination

  colorA = [0.0,1.0,0.0];
  colorB = [1.0,0.5,0.5];
  colorC = [0.5,0.5,0.5];
  colorD = [1.0,1.0,0.0];
  
  cmap = createcolormap(64,colorA,colorB,colorC,colorD); % 64x3 array
  
  surf(peaks); 
  colormap(cmap);
  colorbar;

• RGB matrix

  cmap = createcolormap(rand(10,3)); % 10 random colors
  
  surf(peaks);
  colormap(cmap);
  colorbar;

License

MIT

Author

Takuya Miyashita
Disaster Prevention Research Institute, Kyoto University

Update

v0.1 2021/10/01
v0.2 2021/10/09