to Hex
Convert this color to an RGB hex string.
If renderAlpha is ALWAYS
, the alpha value will be added e.g. the aa
in #ffffffaa
. If it's NEVER
, the alpha will be omitted. If it's AUTO
, then the alpha will be added if it's less than 1.
Return
A string in the form "#ffffff"
if withNumberSign is true, or in the form "ffffff"
otherwise.