Convert between RGB and Color Names

RGB to color name. Color name to RGB. Supports many palettes: CSS, dvips, HTML, MATLAB, RAL, SVG, X11, xcolor, xkcd,...

One function converts between RGB and color names, in both directions.

The function COLORNAMES accepts either RGB values or color names as its inputs, and returns the color names and RGB values from the palette of your choice. The palette is selected by the first input, the trailing inputs are either color names or RGB values:

• Input color name matching is case-insensitive with optional spaces, except for some palettes where whitespace or CamelCase is significant. Diacritics and other special characters are optional.
• Input RGB are matched to the closest palette colors using one of a number of standard color difference metrics. The supported color differences are: CIEDE2000, OkLab, DIN99, CIE94:1, CIE94:2 (default), CIE76 (i.e. CIELAB), CMC2:1, CMC1:1, and RGB.

For more information on color difference metrics: https://en.wikipedia.org/wiki/Color_difference

Whether matching color names or RGB, COLORNAMES always returns the same two output arguments:

1. the color names (string array, or cell array of char vectors).
2. a numeric array of the corresponding RGB values.

A list of the available palettes is returned by calling COLORNAMES with no inputs. A summary of all palettes is printed by calling COLORNAMES with no inputs and no outputs.

Suggestions of interesting palettes (of named colors) are very welcome!

Bonus Functions

• COLORNAMES_CUBE shows palette colors in a 3D cube. The supported colorspaces: Lab, LCh, DIN99, HSV, OKLab, XYZ, and RGB.
• COLORNAMES_VIEW shows palette colors in 2D axes, and sorting them by various colorspace dimensions (e.g. Lab, XYZ, YUV, HSV, or RGB) or alphanumerically by color name.
• COLORNAMES_DELTAE creates a figure comparing the color difference metrics.

Examples

>> palettes = colornames()
palettes =
    'Alphabet'
    'AmstradCPC'
    'AppleII'
    'Bang'
    'BS381C'
    'CGA'
    'Crayola'
    'CSS'
    'dvips'
    'Foster'
    'HTML4'
    'ISCC'
    'Kelly'
    'LeCorbusier'
    'MacBeth'
    'MATLAB'
    'Natural'
    'OsXCrayons'
    'PWG'
    'R'
    'RAL'
    'Resene'
    'Resistor'
    'SherwinWilliams'
    'SVG'
    'Tableau'
    'Thesaurus'
    'Trubetskoy'
    'Wada'
    'Werner'
    'Wikipedia'
    'Wolfram'
    'X11'
    'xcolor'
    'xkcd'

>> colornames('Natural') % all color names for one palette
ans =
    'Black'
    'Blue'
    'Green'
    'Red'
    'White'
    'Yellow'

>> [names,rgb] = colornames('HTML4','blue','RED','Teal','olive')
names =
    'Blue'
    'Red'
    'Teal'
    'Olive'
rgb =
         0         0    1.0000
    1.0000         0         0
         0    0.5020    0.5020
    0.5020    0.5020         0

>> colornames('HTML4',[0,0.5,1;1,0.5,0]) % default deltaE = CIE94:2
ans =
    'Blue'
    'Red'

>> colornames('HTML4',[0,0.5,1;1,0.5,0],'rgb') % specify deltaE
ans =
    'Teal'
    'Olive'

>> colornames("MATLAB",'c','m','y','k')
ans =
    "Cyan"
    "Magenta"
    "Yellow"
    "Black"

>> [names,rgb] = colornames('MATLAB');
>> compose('%s %d %d %d',char(names),rgb)
ans =
    'Black   0 0 0'
    'Blue    0 0 1'
    'Cyan    0 1 1'
    'Green   0 1 0'
    'Magenta 1 0 1'
    'Red     1 0 0'
    'White   1 1 1'
    'Yellow  1 1 0'