RgbToCol: Find the Nearest Named R-Color to a Given RGB-Color

Description

Converting a RGB-color to a named R-Color means looking for a color in the R-palette, which is nearest to the given RGB-color.
This function uses the minimum of squared distance ("euclidean") or the minimum absolute distance ("manhattan") as proximity measure. RgbToLong() converts a RGB-color to a long integer in numeric format. LongToRGB() does it the other way round.

the color in rgb code, say a matrix with the red, green and blue code in the rows.

method

character string specifying the color space to be used. Can be "rgb" (default) or "hsv".

metric

character string specifying the metric to be used for calculating distances between the colors.
Available options are "euclidean" (default) and "manhattan". Euclidean distances are root sum-of-squares of
differences, and manhattan distances are the sum of absolute differences.

Author

Andri Signorell <andri@signorell.net>

Details

It may not be clear from the start which method, rgb or hsv, yield the more natural results. Trying and comparing is a recommended strategy. Moreover the shortest numerical distance will not always be the best choice, when comparing the colours visually.