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A name, assuming that a pointer to an X11-style color names file was compiled in.

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An X11-style hexadecimal specifier: rgb:r/g/b, where r g and b are each 1- to 4-digit hexadecimal numbers.

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An X11-style decimal specifier: rgbi:r/g/b, where r g and b are floating point numbers between 0 and 1.

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For backwards compatibility, an old-X11-style hexadecimal number: #rgb, #rrggbb, #rrrgggbbb, or #rrrrggggbbbb.

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For backwards compatibility, a triplet of numbers separated by commas: r,g,b, where r g and b are floating point numbers between 0 and 1. (This style was added before MIT came up with the similar rgbi style.)