PdfColorCmyk constructor
Creates a CMYK color
Implementation
const PdfColorCmyk(this.cyan, this.magenta, this.yellow, this.black,
[double a = 1.0])
: super((1.0 - cyan) * (1.0 - black), (1.0 - magenta) * (1.0 - black),
(1.0 - yellow) * (1.0 - black), a);