**(hsla: // [[harlowe:Number|Number]], Number, Number, Number//) -> //[[harlowe:Colour|colour]]//** A special version of [[harlowe:hsl|(hsl:)]], this macro allows you to supply not just the hue (h) angle in degrees, saturation (s) and lightness (l) percentages, but also the transparency (alpha, or a) percentage, which is a fractional value between 0 (fully transparent) and 1 (fully visible). Anything drawn with a partially transparent [[harlowe:colour|colour]] will itself be partially transparent. You can then layer such elements to produce a few interesting visual effects. === Example usage: === ''%%(hsla: 120, 0.5, 0.8, 0.6)%%'' produces a 40% transparent faint green. === Details: === This macro takes the same range of [[harlowe:number|number]] as the CSS ''%%rgba()%%'' function. Giving alpha percentages higher than 1 or lower than 0 will cause an error. === See also: === [[harlowe:rgb|(rgb:)]], [[harlowe:rgba|(rgba:)]], [[harlowe:hsl|(hsl:)]]