magic zero value to indicate end of painting.
This means that Painter implementations can assume thant the Spans' Y
values are monotonic.
R=rsc
CC=golang-dev, rog
http://codereview.appspot.com/1261043
draw text onto an image.
This is a simple API that doesn't handle line breaking, ligatures,
right-to-left or vertical scripts, and other fancy features.
R=r, rsc
CC=golang-dev
http://codereview.appspot.com/1121045
Parsing a malformed TTF may result in an index out-of-bounds panic,
rather than guaranteeing to return an error. This may be tightened
in the future.
R=r, rsc
CC=golang-dev
http://codereview.appspot.com/940044