Usage

Import the library:

import de.kompf.colormapsmpl.*;

Instantiate the colormap registry:

ColorMapRegistry creg = new ColorMapRegistry();

Register one or multiple colormap categories:

creg.registerCategorySequential();

creg.registerCategorySequential2();

creg.registerCategoryDiverging();

creg.registerCategoryQualitative();

creg.registerCategoryMiscellaneous();

creg.registerCategoryPerceptuallyUniformSequential();

creg.registerCategoryCyclic();

It is also possible to register all colormaps at once:

creg.registerAllCategories();

For a deeper explanation of the colormaps, see Choosing Colormaps in Matplotlib.

Retrieve a color map by its name:

ColorMap cmap = creg.getColorMap("Blues");

For a reference of all names see this reference. All names that are currently registered in the ColorMapRegistry may be retrieved with:

creg.getAllNames();

Retrieve and use the colors:

To retrieve the color for value val:

int color = cmap.getColor(val);

The argument val must no exceed the range of 0 to cmap.size()-1. For most colormaps, this is the range from 0 to 255 (inclusive). However, colormaps from the Qualitative category often have fewer colors, so be sure to use Processing's map function to map your data range to the number of available colors..

The result is a 32-bit value ordered as AAAAAAAARRRRRRRRGGGGGGGGBBBBBBBB, which can be fed directly into Processing's fill, stroke or background functions, if the default RGB color model is active.

Example usage:

For example, if we have a variable val with values in the range minVal..maxVal and want to represent this variable as a fill color, we would use:

colorMode(RGB); // can be omitted as this is the default setting

int icol = (int)map(val, minVal, maxVal, 0, cmap.size()-1);
fill(cmap.getColor(icol));