func drawContour(r *raster.Rasterizer, ps []truetype.Point, dx, dy raster.Fix32) {
if len(ps) == 0 {
return
}
// ps[0] is a truetype.Point measured in FUnits and positive Y going upwards.
// start is the same thing measured in fixed point units and positive Y
// going downwards, and offset by (dx, dy)
start := raster.Point{
X: dx + raster.Fix32(ps[0].X<<2),
Y: dy - raster.Fix32(ps[0].Y<<2),
}
r.Start(start)
q0, on0 := start, true
for _, p := range ps[1:] {
q := raster.Point{
X: dx + raster.Fix32(p.X<<2),
Y: dy - raster.Fix32(p.Y<<2),
}
on := p.Flags&0x01 != 0
if on {
if on0 {
r.Add1(q)
} else {
r.Add2(q0, q)
}
} else {
if on0 {
// No-op.
} else {
mid := raster.Point{
X: (q0.X + q.X) / 2,
Y: (q0.Y + q.Y) / 2,
}
r.Add2(q0, mid)
}
}
q0, on0 = q, on
}
// Close the curve.
if on0 {
r.Add1(start)
} else {
r.Add2(q0, start)
}
}
func contour(r *raster.Rasterizer, ns []node) {
if len(ns) == 0 {
return
}
i := 0
r.Start(p(ns[i]))
for {
switch ns[i].degree {
case -1:
// -1 signifies end-of-contour.
return
case 1:
i += 1
r.Add1(p(ns[i]))
case 2:
i += 2
r.Add2(p(ns[i-1]), p(ns[i]))
default:
panic("bad degree")
}
}
}