Regex for some common color code formats (for ruby).

regex_gist.rb

# NOTE: whitespaces between the number and the "," in the parentheses are optional.

RGB = /^rgb\((\d{1,2}|([01][0-9][0-9]|((25[0-5])|2[0-4]\d))),(| )(\d{1,2}|([01][0-9][0-9]|((25[0-5])|2[0-4]\d))),(| )(\d{1,2}|([01][0-9][0-9]|((25[0-5])|2[0-4]\d)))\)$/i
RGBA = /^rgba\((\d{1,2}|([01][0-9][0-9]|((25[0-5])|2[0-4]\d))),(| )(\d{1,2}|([01][0-9][0-9]|((25[0-5])|2[0-4]\d))),(| )(\d{1,2}|([01][0-9][0-9]|((25[0-5])|2[0-4]\d)))(,|, )(0|1|0.\d|1.0)\)$/i
HEXA = /^#(\d|[a-f])(\d|[a-f])(\d|[a-f])(|(\d|[a-f]))$/i
HEX = /^#(\d|[a-f])(\d|[a-f])(\d|[a-f])$/i
HHEEXX = /^#(\d\d|\d[a-f]|[a-f]\d|[a-f][a-f])(\d\d|\d[a-f]|[a-f]\d|[a-f][a-f])(\d\d|\d[a-f]|[a-f]\d|[a-f][a-f])$/i
HHEEXXAA = /^#(\d\d|\d[a-f]|[a-f]\d|[a-f][a-f])(\d\d|\d[a-f]|[a-f]\d|[a-f][a-f])(\d\d|\d[a-f]|[a-f]\d|[a-f][a-f])(|(\d\d|\d[a-f]|[a-f]\d|[a-f][a-f]))$/i
HSL = /^hsl\((\d|\d\d|[1-2]\d{2}|(3([0-5]\d|60))),(| )(\d|\d\d|100)%,(| )(\d|\d\|100)%\)$/i
HSLA = /^hsla\((\d|\d\d|[1-2]\d{2}|(3([0-5]\d|60))),(| )(\d|\d\d|100)%,(| )(\d|\d\|100)%(,|, )(1.0|0|1,0.\d)\)$/i