[racket-dev] Adding alpha to color%

I would like to add alpha to `color%', but I haven't gotten around to it.

At Wed, 24 Nov 2010 17:28:33 +0000, Noel Welsh wrote:
> Why was the alpha channel made a property of the dc, rather than (in
> addition to) the color? For some use cases specifying alpha as part of
> the colour is more convenient, and Cairo supports both IIRC. (That is,
> you can specify alpha as part of a color or as part of the drawing
> process.)
> 
> N.