import "code.google.com/p/freetype-go/freetype/raster" 

type RGBAPainter
func NewRGBAPainter(m *image.RGBA) *RGBAPainter
func (r *RGBAPainter) Paint(ss []Span, done bool)
func (r *RGBAPainter) SetColor(c color.Color)

The raster package provides an anti-aliasing 2-D rasterizer.

It is part of the larger Freetype-Go suite of font-related packages but the raster package is not specific to font rasterization and can be used standalone without any other Freetype-Go package.

Rasterization is done by the same area/coverage accumulation algorithm as the Freetype “smooth” module and the Anti-Grain Geometry library. A description of the area/coverage algorithm is at http://projects.tuxee.net/cl-vectors/section-the-cl-aa-algorithm