parse_with_alpha

Fill in the fields of a color from a string specification.

The string can either one of a large set of standard names. (Taken from the CSS Color [specification](https://www.w3.org/TR/css-color-4/ named-colors), or it can be a hexadecimal value in the form `rgb`, `rrggbb`, `rrrgggbbb ` or `rrrrggggbbbb` where `r`, `g` and `b` are hex digits of the red, green, and blue components of the color, respectively. (White in the four forms is `fff`, `ffffff`, `fffffffff` and `ffffffffffff `.)

Additionally, parse strings of the form `rgba`, `rrggbbaa`, `rrrrggggbbbbaaaa`, if alpha is not null, and set alpha to the value specified by the hex digits for `a`. If no alpha component is found in spec, alpha is set to 0xffff (for a solid color).

Parameters:

this	a `PangoColor` structure in which to store the result
alpha	return location for alpha
spec	a string specifying the new color

Returns:

true if parsing of the specifier succeeded, otherwise false