[gsoc] acme selection is finally fixed!

From: David Hoskin <root@davidrhoskin.com>
To: "gsoc2014david" <gsoc2014david@9atom.org>
Date: Sat, 31 May 2014 11:57:00 -0700
Subject: [gsoc] acme selection is finally fixed!

I wound up reading acme to see how it was drawing selections,
which led me to
/sys/src/libframe/frdraw.c:/^frdrawsel

Seeing that it was making a raw draw() call (I expected fillpoly) prompted
me to look at my handling of /dev/draw/n/ctl's `d' message. It turned
out to be ancient code discarding the mask entirely, because I had
last touched it before I wrote drawmasked()!

Replacing it with my fancy new drawmasked() fixed the selection
problem entirely, and also mysteriously fixed the oversaturated
colours I was seeing.

It took so long to find because I expected the problem to be somewhere
in my memdraw implementation, and completely forgot about the
/dev/draw code itself.

Patch imminent.

-- David