libnkutils Colour format: libnkutils Reference Manual

libnkutils Colour format

Colour format — textual representation of NkColour

Colour strings

The colour string format is borrowed from the CSS4 colour values. Hexadecimal (#-prefixed) and decimal (rgb() format) RGB(A) notations are supported.

Here is a quick description:

`#RRGGBB[AA]`, `#RGB[A]`	Each value is an hexadecimal value in the `0x00`-`0xff` range. The alpha value is an extension of the CSS3 notation and is optional. The single-letter version means duplicating the character (e.g. `"#123"` means `"#112233"`).
`rgb(red, green, blue)`, `rgba(red, green, blue, alpha)`	Each colour value can be an number in the `0`-`255` range or a percentage value. The alpha value is a floating point or a percentage value.
`hsl(hue, saturation, lightness)`, `hsla(hue, saturation, lightness, alpha)`	Hue is an angle either in degrees (unit `deg` or no unit), gradians (unit `grab`), radians (unit `rad`) or turns (unit `turn`, a floating point number from `0` to `1`). The saturation and lightness values are percentage values. The alpha value is the same as the `rgba()` notation.
`hwb(hue, whiteness, blackness[, alpha])`	Hue is the same as the `hsl()` notation. The whiteness and blackness values are percentage values. The alpha value is the same as the `rgba()` notation.