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// Copyright 2010 The draw2d Authors. All rights reserved.
// created: 21/11/2010 by Laurent Le Goff
package draw2d
/*
import (
"image/draw"
"image"
"freetype-go.googlecode.com/hg/freetype/raster"
)*/
const M = 1<<16 - 1
/*
type NRGBAPainter struct {
// The image to compose onto.
Image *image.NRGBA
// The Porter-Duff composition operator.
Op draw.Op
// The 16-bit color to paint the spans.
cr, cg, cb, ca uint32
}
// Paint satisfies the Painter interface by painting ss onto an image.RGBA.
func (r *NRGBAPainter) Paint(ss []raster.Span, done bool) {
b := r.Image.Bounds()
for _, s := range ss {
if s.Y < b.Min.Y {
continue
}
if s.Y >= b.Max.Y {
return
}
if s.X0 < b.Min.X {
s.X0 = b.Min.X
}
if s.X1 > b.Max.X {
s.X1 = b.Max.X
}
if s.X0 >= s.X1 {
continue
}
base := s.Y * r.Image.Stride
p := r.Image.Pix[base+s.X0 : base+s.X1]
// This code is duplicated from drawGlyphOver in $GOROOT/src/pkg/image/draw/draw.go.
// TODO(nigeltao): Factor out common code into a utility function, once the compiler
// can inline such function calls.
ma := s.A >> 16
if r.Op == draw.Over {
for i, nrgba := range p {
dr, dg, db, da := nrgba.
a := M - (r.ca*ma)/M
da = (da*a + r.ca*ma) / M
if da != 0 {
dr = minUint32(M, (dr*a+r.cr*ma)/da)
dg = minUint32(M, (dg*a+r.cg*ma)/da)
db = minUint32(M, (db*a+r.cb*ma)/da)
} else {
dr, dg, db = 0, 0, 0
}
p[i] = image.NRGBAColor{uint8(dr >> 8), uint8(dg >> 8), uint8(db >> 8), uint8(da >> 8)}
}
} else {
for i, nrgba := range p {
dr, dg, db, da := nrgba.RGBA()
a := M - ma
da = (da*a + r.ca*ma) / M
if da != 0 {
dr = minUint32(M, (dr*a+r.cr*ma)/da)
dg = minUint32(M, (dg*a+r.cg*ma)/da)
db = minUint32(M, (db*a+r.cb*ma)/da)
} else {
dr, dg, db = 0, 0, 0
}
p[i] = image.NRGBAColor{uint8(dr >> 8), uint8(dg >> 8), uint8(db >> 8), uint8(da >> 8)}
}
}
}
}
// SetColor sets the color to paint the spans.
func (r *NRGBAPainter) SetColor(c image.Color) {
r.cr, r.cg, r.cb, r.ca = c.RGBA()
}
// NewRGBAPainter creates a new RGBAPainter for the given image.
func NewNRGBAPainter(m *image.NRGBA) *NRGBAPainter {
return &NRGBAPainter{Image: m}
}
*/
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