single place to contain Color-Name mapping. These include an old set of 10 or so color names, plus the 130 or so web color names like "SaddleBrown" and "DarkOrchid".
decode the color, throwing a RuntimeException when the color is not parsable. Valid entries include:
return either a named color or #00aaff for opaque colors and #80aaff00 for transparent colors.
return a map of the named colors.
return standard color for slightly masking background.
return the preferred name for the color