1 files changed, 506 insertions, 0 deletions
diff --git a/libgo/go/image/image.go b/libgo/go/image/image.go
new file mode 100644
index 000000000..c0e96e1f7
--- /dev/null
+++ b/libgo/go/image/image.go
@@ -0,0 +1,506 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The image package implements a basic 2-D image library.
+package image
+
+// A Config consists of an image's color model and dimensions.
+type Config struct {
+	ColorModel    ColorModel
+	Width, Height int
+}
+
+// An Image is a finite rectangular grid of Colors drawn from a ColorModel.
+type Image interface {
+	// ColorModel returns the Image's ColorModel.
+	ColorModel() ColorModel
+	// Bounds returns the domain for which At can return non-zero color.
+	// The bounds do not necessarily contain the point (0, 0).
+	Bounds() Rectangle
+	// At returns the color of the pixel at (x, y).
+	// At(Bounds().Min.X, Bounds().Min.Y) returns the upper-left pixel of the grid.
+	// At(Bounds().Max.X-1, Bounds().Max.Y-1) returns the lower-right one.
+	At(x, y int) Color
+}
+
+// An RGBA is an in-memory image of RGBAColor values.
+type RGBA struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []RGBAColor
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *RGBA) ColorModel() ColorModel { return RGBAColorModel }
+
+func (p *RGBA) Bounds() Rectangle { return p.Rect }
+
+func (p *RGBA) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return RGBAColor{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *RGBA) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toRGBAColor(c).(RGBAColor)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *RGBA) Opaque() bool {
+	if p.Rect.Empty() {
+		return true
+	}
+	base := p.Rect.Min.Y * p.Stride
+	i0, i1 := base+p.Rect.Min.X, base+p.Rect.Max.X
+	for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
+		for _, c := range p.Pix[i0:i1] {
+			if c.A != 0xff {
+				return false
+			}
+		}
+		i0 += p.Stride
+		i1 += p.Stride
+	}
+	return true
+}
+
+// NewRGBA returns a new RGBA with the given width and height.
+func NewRGBA(w, h int) *RGBA {
+	buf := make([]RGBAColor, w*h)
+	return &RGBA{buf, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// An RGBA64 is an in-memory image of RGBA64Color values.
+type RGBA64 struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []RGBA64Color
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *RGBA64) ColorModel() ColorModel { return RGBA64ColorModel }
+
+func (p *RGBA64) Bounds() Rectangle { return p.Rect }
+
+func (p *RGBA64) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return RGBA64Color{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *RGBA64) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toRGBA64Color(c).(RGBA64Color)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *RGBA64) Opaque() bool {
+	if p.Rect.Empty() {
+		return true
+	}
+	base := p.Rect.Min.Y * p.Stride
+	i0, i1 := base+p.Rect.Min.X, base+p.Rect.Max.X
+	for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
+		for _, c := range p.Pix[i0:i1] {
+			if c.A != 0xffff {
+				return false
+			}
+		}
+		i0 += p.Stride
+		i1 += p.Stride
+	}
+	return true
+}
+
+// NewRGBA64 returns a new RGBA64 with the given width and height.
+func NewRGBA64(w, h int) *RGBA64 {
+	pix := make([]RGBA64Color, w*h)
+	return &RGBA64{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// An NRGBA is an in-memory image of NRGBAColor values.
+type NRGBA struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []NRGBAColor
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *NRGBA) ColorModel() ColorModel { return NRGBAColorModel }
+
+func (p *NRGBA) Bounds() Rectangle { return p.Rect }
+
+func (p *NRGBA) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return NRGBAColor{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *NRGBA) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toNRGBAColor(c).(NRGBAColor)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *NRGBA) Opaque() bool {
+	if p.Rect.Empty() {
+		return true
+	}
+	base := p.Rect.Min.Y * p.Stride
+	i0, i1 := base+p.Rect.Min.X, base+p.Rect.Max.X
+	for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
+		for _, c := range p.Pix[i0:i1] {
+			if c.A != 0xff {
+				return false
+			}
+		}
+		i0 += p.Stride
+		i1 += p.Stride
+	}
+	return true
+}
+
+// NewNRGBA returns a new NRGBA with the given width and height.
+func NewNRGBA(w, h int) *NRGBA {
+	pix := make([]NRGBAColor, w*h)
+	return &NRGBA{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// An NRGBA64 is an in-memory image of NRGBA64Color values.
+type NRGBA64 struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []NRGBA64Color
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *NRGBA64) ColorModel() ColorModel { return NRGBA64ColorModel }
+
+func (p *NRGBA64) Bounds() Rectangle { return p.Rect }
+
+func (p *NRGBA64) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return NRGBA64Color{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *NRGBA64) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toNRGBA64Color(c).(NRGBA64Color)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *NRGBA64) Opaque() bool {
+	if p.Rect.Empty() {
+		return true
+	}
+	base := p.Rect.Min.Y * p.Stride
+	i0, i1 := base+p.Rect.Min.X, base+p.Rect.Max.X
+	for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
+		for _, c := range p.Pix[i0:i1] {
+			if c.A != 0xffff {
+				return false
+			}
+		}
+		i0 += p.Stride
+		i1 += p.Stride
+	}
+	return true
+}
+
+// NewNRGBA64 returns a new NRGBA64 with the given width and height.
+func NewNRGBA64(w, h int) *NRGBA64 {
+	pix := make([]NRGBA64Color, w*h)
+	return &NRGBA64{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// An Alpha is an in-memory image of AlphaColor values.
+type Alpha struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []AlphaColor
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *Alpha) ColorModel() ColorModel { return AlphaColorModel }
+
+func (p *Alpha) Bounds() Rectangle { return p.Rect }
+
+func (p *Alpha) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return AlphaColor{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *Alpha) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toAlphaColor(c).(AlphaColor)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *Alpha) Opaque() bool {
+	if p.Rect.Empty() {
+		return true
+	}
+	base := p.Rect.Min.Y * p.Stride
+	i0, i1 := base+p.Rect.Min.X, base+p.Rect.Max.X
+	for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
+		for _, c := range p.Pix[i0:i1] {
+			if c.A != 0xff {
+				return false
+			}
+		}
+		i0 += p.Stride
+		i1 += p.Stride
+	}
+	return true
+}
+
+// NewAlpha returns a new Alpha with the given width and height.
+func NewAlpha(w, h int) *Alpha {
+	pix := make([]AlphaColor, w*h)
+	return &Alpha{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// An Alpha16 is an in-memory image of Alpha16Color values.
+type Alpha16 struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []Alpha16Color
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *Alpha16) ColorModel() ColorModel { return Alpha16ColorModel }
+
+func (p *Alpha16) Bounds() Rectangle { return p.Rect }
+
+func (p *Alpha16) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return Alpha16Color{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *Alpha16) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toAlpha16Color(c).(Alpha16Color)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *Alpha16) Opaque() bool {
+	if p.Rect.Empty() {
+		return true
+	}
+	base := p.Rect.Min.Y * p.Stride
+	i0, i1 := base+p.Rect.Min.X, base+p.Rect.Max.X
+	for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
+		for _, c := range p.Pix[i0:i1] {
+			if c.A != 0xffff {
+				return false
+			}
+		}
+		i0 += p.Stride
+		i1 += p.Stride
+	}
+	return true
+}
+
+// NewAlpha16 returns a new Alpha16 with the given width and height.
+func NewAlpha16(w, h int) *Alpha16 {
+	pix := make([]Alpha16Color, w*h)
+	return &Alpha16{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// A Gray is an in-memory image of GrayColor values.
+type Gray struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []GrayColor
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *Gray) ColorModel() ColorModel { return GrayColorModel }
+
+func (p *Gray) Bounds() Rectangle { return p.Rect }
+
+func (p *Gray) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return GrayColor{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *Gray) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toGrayColor(c).(GrayColor)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *Gray) Opaque() bool {
+	return true
+}
+
+// NewGray returns a new Gray with the given width and height.
+func NewGray(w, h int) *Gray {
+	pix := make([]GrayColor, w*h)
+	return &Gray{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// A Gray16 is an in-memory image of Gray16Color values.
+type Gray16 struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []Gray16Color
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *Gray16) ColorModel() ColorModel { return Gray16ColorModel }
+
+func (p *Gray16) Bounds() Rectangle { return p.Rect }
+
+func (p *Gray16) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return Gray16Color{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *Gray16) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toGray16Color(c).(Gray16Color)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *Gray16) Opaque() bool {
+	return true
+}
+
+// NewGray16 returns a new Gray16 with the given width and height.
+func NewGray16(w, h int) *Gray16 {
+	pix := make([]Gray16Color, w*h)
+	return &Gray16{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// A PalettedColorModel represents a fixed palette of colors.
+type PalettedColorModel []Color
+
+func diff(a, b uint32) uint32 {
+	if a > b {
+		return a - b
+	}
+	return b - a
+}
+
+// Convert returns the palette color closest to c in Euclidean R,G,B space.
+func (p PalettedColorModel) Convert(c Color) Color {
+	if len(p) == 0 {
+		return nil
+	}
+	cr, cg, cb, _ := c.RGBA()
+	// Shift by 1 bit to avoid potential uint32 overflow in sum-squared-difference.
+	cr >>= 1
+	cg >>= 1
+	cb >>= 1
+	result := Color(nil)
+	bestSSD := uint32(1<<32 - 1)
+	for _, v := range p {
+		vr, vg, vb, _ := v.RGBA()
+		vr >>= 1
+		vg >>= 1
+		vb >>= 1
+		dr, dg, db := diff(cr, vr), diff(cg, vg), diff(cb, vb)
+		ssd := (dr * dr) + (dg * dg) + (db * db)
+		if ssd < bestSSD {
+			bestSSD = ssd
+			result = v
+		}
+	}
+	return result
+}
+
+// A Paletted is an in-memory image backed by a 2-D slice of uint8 values and a PalettedColorModel.
+type Paletted struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []uint8
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+	// Palette is the image's palette.
+	Palette PalettedColorModel
+}
+
+func (p *Paletted) ColorModel() ColorModel { return p.Palette }
+
+func (p *Paletted) Bounds() Rectangle { return p.Rect }
+
+func (p *Paletted) At(x, y int) Color {
+	if len(p.Palette) == 0 {
+		return nil
+	}
+	if !p.Rect.Contains(Point{x, y}) {
+		return p.Palette[0]
+	}
+	return p.Palette[p.Pix[y*p.Stride+x]]
+}
+
+func (p *Paletted) ColorIndexAt(x, y int) uint8 {
+	if !p.Rect.Contains(Point{x, y}) {
+		return 0
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *Paletted) SetColorIndex(x, y int, index uint8) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = index
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *Paletted) Opaque() bool {
+	for _, c := range p.Palette {
+		_, _, _, a := c.RGBA()
+		if a != 0xffff {
+			return false
+		}
+	}
+	return true
+}
+
+// NewPaletted returns a new Paletted with the given width, height and palette.
+func NewPaletted(w, h int, m PalettedColorModel) *Paletted {
+	pix := make([]uint8, w*h)
+	return &Paletted{pix, w, Rectangle{ZP, Point{w, h}}, m}
+}