func palettedToRGBA(last *image.RGBA, in *image.Paletted) *image.RGBA {
out := image.NewRGBA(image.Rect(0, 0, 16, 16))
draw.Draw(out, out.Bounds(), last, last.Rect.Min, draw.Src)
draw.Draw(out, in.Bounds(), in, in.Rect.Min, draw.Over)
return out
}
func pixel_is_light(img *image.Paletted, x int, y int) bool {
r, g, b, _ := img.At(x, y).RGBA()
sum := r + g + b
return (sum > 0x18000) && (sum < 0x2e000)
}
// 全填充正方形
//
// --------
// |######|
// |######|
// |######|
// --------
func b1(img *image.Paletted, x, y, size float64, angle int) {
isize := int(size)
ix := int(x)
iy := int(y)
for i := ix + 1; i < ix+isize; i++ {
for j := iy + 1; j < iy+isize; j++ {
img.SetColorIndex(i, j, 1)
}
}
}
func newSetFuncPaletted(p *image.Paletted) SetFunc {
return func(x, y int, r, g, b, a uint32) {
i := p.PixOffset(x, y)
p.Pix[i] = uint8(p.Palette.Index(color.RGBA64{
R: uint16(r),
G: uint16(g),
B: uint16(b),
A: uint16(a),
}))
}
}
// 中间小方块
// ----------
// | |
// | #### |
// | #### |
// | |
// ----------
func b2(img *image.Paletted, x, y, size float64, angle int) {
l := size / 4
x = x + l
y = y + l
for i := x; i < x+2*l; i++ {
for j := y; j < y+2*l; j++ {
img.SetColorIndex(int(i), int(j), 1)
}
}
}
func toPaletted(o *ora.ORA, name string, palette color.Palette) (*image.Paletted, error) {
var p *image.Paletted
if l := o.Layer(name); l != nil {
p = image.NewPaletted(o.Bounds(), palette)
i, err := l.Image()
if err != nil {
return nil, err
}
draw.Draw(p, image.Rect(0, 0, p.Bounds().Max.X, p.Bounds().Max.Y), i, image.Point{}, draw.Src)
}
return p, nil
}
func (s *Simulation) DrawAll(initialImage *image.Paletted, frameCount int) []*image.Paletted {
bounds := initialImage.Bounds()
images := make([]*image.Paletted, frameCount)
s.Draw(initialImage)
images[0] = initialImage
for f := 1; f < frameCount; f++ {
newSimulation := s.Step()
img := image.NewPaletted(bounds, initialImage.Palette)
newSimulation.DiffDraw(s, img)
images[f] = img
s = newSimulation
}
return images
}
// Write a text inside the image
func WriteText(text string, f *truetype.Font, img *image.Paletted) {
// Initialize the context.
fg := image.Black
c := freetype.NewContext()
c.SetDPI(72)
c.SetFont(f)
c.SetFontSize(64)
c.SetClip(img.Bounds())
c.SetDst(img)
c.SetSrc(fg)
// Draw the text.
pt := freetype.Pt(40, 120)
c.DrawString(text, pt)
}
// 将多边形points旋转angle个角度，然后输出到img上，起点为x,y坐标
func drawBlock(img *image.Paletted, x, y, size float64, angle int, points []float64) {
if angle > 0 { // 0角度不需要转换
// 中心坐标与x,y的距离，方便下面指定中心坐标(x+m,y+m)，
// 0.5的偏移值不能少，否则坐靠右，非正中央
m := size/2 - 0.5
rotate(points, x+m, y+m, angle)
}
for i := x; i < x+size; i++ {
for j := y; j < y+size; j++ {
if pointInPolygon(i, j, points) {
img.SetColorIndex(int(i), int(j), 1)
}
}
}
}
// uninterlace rearranges the pixels in m to account for interlaced input.
func uninterlace(m *image.Paletted) {
var nPix []uint8
dx := m.Bounds().Dx()
dy := m.Bounds().Dy()
nPix = make([]uint8, dx*dy)
offset := 0 // steps through the input by sequential scan lines.
for _, pass := range interlacing {
nOffset := pass.start * dx // steps through the output as defined by pass.
for y := pass.start; y < dy; y += pass.skip {
copy(nPix[nOffset:nOffset+dx], m.Pix[offset:offset+dx])
offset += dx
nOffset += dx * pass.skip
}
}
m.Pix = nPix
}
func modeTerrain(p *image.Paletted, l int) uint8 {
b := p.Bounds()
modeMap := make([]uint8, l)
var most, mode uint8
for i := b.Min.X; i < b.Max.X; i++ {
for j := b.Min.Y; j < b.Max.Y; j++ {
pos := p.ColorIndexAt(i, j)
modeMap[pos]++
if m := modeMap[pos]; m > most {
most = m
mode = pos
}
}
}
return mode
}
func untile(m *image.Paletted, data []byte) {
w, h := m.Rect.Dx(), m.Rect.Dy()
for i, x := 0, 0; x < w; x += 8 {
for y := 0; y < h; y += 8 {
for ty := 0; ty < 8; ty++ {
pix := mingle(uint16(data[i]), uint16(data[i+1]))
for tx := 7; tx >= 0; tx-- {
i := m.PixOffset(x+tx, y+ty)
m.Pix[i] = uint8(pix & 3)
pix >>= 2
}
i += 2
}
}
}
}
func ripShinyPokemonBack(rip *sprites.Ripper, number int, form string, outname string) error {
var m *image.Paletted
var err error
if number == 201 && form != "" {
m, err = rip.UnownBack(form)
} else {
m, err = rip.PokemonBack(number)
}
if err != nil {
return err
}
m.Palette = rip.ShinyPalette(number)
if m.Palette == nil {
return errors.New("couldn't get palette")
}
return write(m, outname)
}
func debarf_frame(frame *image.Paletted) error {
xmin := frame.Rect.Min.X
ymin := frame.Rect.Min.Y
xmax := frame.Rect.Max.X
ymax := frame.Rect.Max.Y
for y := ymin; y < ymax; y++ {
for x := xmin; x < xmax; x++ {
c := frame.At(x, y)
r, g, b, a := c.RGBA()
if pixel_is_transparent(frame, x, y) {
fmt.Printf("...")
frame.Set(x, y, color.RGBA64{uint16(r), uint16(g), uint16(b), 0xffff})
} else if should_turn_pixel_transparent(frame, x, y) {
fmt.Printf("xxx")
frame.Set(x, y, color.RGBA64{0, 0, 0, 0xffff})
} else {
r /= 0x1000
g /= 0x1000
b /= 0x1000
if a != 0xffff {
fmt.Printf("barf")
}
fmt.Printf("%x%x%x", r, g, b)
}
}
fmt.Printf("\n")
}
return nil
}
func (q *MedianCutQuantizer) Quantize(dst *image.Paletted, r image.Rectangle, src image.Image, sp image.Point) {
clip(dst, &r, src, &sp)
if r.Empty() {
return
}
points := make([]point, r.Dx()*r.Dy())
colorSet := make(map[uint32]color.Color, q.NumColor)
i := 0
for y := r.Min.Y; y < r.Max.Y; y++ {
for x := r.Min.X; x < r.Max.X; x++ {
c := src.At(x, y)
r, g, b, _ := c.RGBA()
colorSet[(r>>8)<<16|(g>>8)<<8|b>>8] = c
points[i][0] = int(r)
points[i][1] = int(g)
points[i][2] = int(b)
i++
}
}
if len(colorSet) <= q.NumColor {
// No need to quantize since the total number of colors
// fits within the palette.
dst.Palette = make(color.Palette, len(colorSet))
i := 0
for _, c := range colorSet {
dst.Palette[i] = c
i++
}
} else {
dst.Palette = q.medianCut(points)
}
for y := 0; y < r.Dy(); y++ {
for x := 0; x < r.Dx(); x++ {
// TODO: this should be done more efficiently.
dst.Set(sp.X+x, sp.Y+y, src.At(r.Min.X+x, r.Min.Y+y))
}
}
}
// Merge les deux images de telle sorte qu'après l'opération les pixels de img1 :
// - soient inchangés là où l'index dans img2 est 0
// - prennent la valeur de img2 ailleurs
// Les deux images doivent être de mêmes dimensions exactement
// La palette de img1 est enrichie si nécessaire
func Fusionne(img1 *image.Paletted, img2 *image.Paletted) error {
r1 := img1.Bounds()
r2 := img2.Bounds()
if r1.Min.X != r2.Min.X || r1.Max.X != r2.Max.X || r1.Min.Y != r2.Min.Y || r1.Max.Y != r2.Max.Y {
return errors.New("image dimensions not compatible")
}
p1 := img1.Palette
p2 := img2.Palette
n1 := len(p1)
n2 := len(p2)
op := make([]uint8, n2) // tableau donnant l'index dans la palette de img1 d'une couleur de la palette de img2
for i2 := 0; i2 < n2; i2++ {
c := p2[i2].(color.RGBA)
if i2 < n1 && couleursEgales(c, p1[i2].(color.RGBA)) {
op[i2] = uint8(i2)
} else {
found := false
for i1 := 0; i1 < n1; i1++ {
if couleursEgales(c, p1[i1].(color.RGBA)) {
op[i2] = uint8(i1)
found = true
break
}
}
if !found {
op[i2] = uint8(len(p1))
p1 = append(p1, c)
img1.Palette = p1
}
}
}
l2 := len(img2.Pix)
for x := 0; x < l2; x++ {
if img2.Pix[x] != 0 {
img1.Pix[x] = op[img2.Pix[x]]
}
}
return nil
}
func (d *decoder) uninterlace(m *image.Paletted) {
if d.imageFields&ifInterlace == 0 {
return
}
var nPix []uint8
dx := d.width
dy := d.height
nPix = make([]uint8, dx*dy)
offset := 0 // steps through the input by sequentical scan lines.
for _, pass := range interlacing {
nOffset := pass.start * dx // steps through the output as defined by pass.
for y := pass.start; y < dy; y += pass.skip {
copy(nPix[nOffset:nOffset+dx], m.Pix[offset:offset+dx])
offset += dx
nOffset += dx * pass.skip
}
}
m.Pix = nPix
}
func encodeImageBlock(w io.Writer, img *image.Paletted) error {
// start image
litWidth := int(paletteBits(img.Palette))
if litWidth < 2 {
litWidth = 2
}
bounds := img.Bounds()
if err := writeData(w,
byte(0x2C),
uint16(bounds.Min.X), uint16(bounds.Min.Y), uint16(bounds.Dx()), uint16(bounds.Dy()),
byte(0),
byte(litWidth),
); err != nil {
return err
}
// start compression
blocks := &blockWriter{w: w}
compress := lzw.NewWriter(blocks, lzw.LSB, litWidth)
// write each scan line (might not be contiguous)
startX := img.Rect.Min.X
stopX := img.Rect.Max.X
stopY := img.Rect.Max.Y
for y := img.Rect.Min.Y; y < stopY; y++ {
start := img.PixOffset(startX, y)
stop := img.PixOffset(stopX, y)
if _, err := compress.Write(img.Pix[start:stop]); err != nil {
return err
}
}
if err := compress.Close(); err != nil {
return err
}
return blocks.Close()
}
func (g *generator) buildTerrain(mpath minecraft.Path, level *level, terrain, biomes, plants *image.Paletted, height, water *image.Gray, c chan paint) error {
b := terrain.Bounds()
proceed := make(chan uint8, 10)
errChan := make(chan error, 1)
go func() {
defer close(proceed)
cc := newCache(g.Terrain.Blocks)
for j := 0; j < b.Max.Y; j += 16 {
chunkZ := int32(j >> 4)
for i := 0; i < b.Max.X; i += 16 {
chunkX := int32(i >> 4)
h := int32(meanHeight(height.SubImage(image.Rect(i, j, i+16, j+16)).(*image.Gray)))
wh := int32(meanHeight(water.SubImage(image.Rect(i, j, i+16, j+16)).(*image.Gray)))
var t uint8
if wh >= h<<1 { // more water than land...
c <- paint{
color.RGBA{0, 0, 255, 255},
chunkX, chunkZ,
}
t = uint8(len(g.Terrain.Blocks) - 1)
h = wh
} else {
t = modeTerrain(terrain.SubImage(image.Rect(i, j, i+16, j+16)).(*image.Paletted), len(g.Terrain.Palette))
c <- paint{
g.Terrain.Palette[t],
chunkX, chunkZ,
}
}
if err := mpath.SetChunk(cc.getFromCache(chunkX, chunkZ, t, h)); err != nil {
errChan <- err
return
}
proceed <- t
}
}
}()
ts := make([]uint8, 0, 1024)
for i := 0; i < (b.Max.X>>4)+2; i++ {
ts = append(ts, <-proceed) // get far enough ahead so all chunks are surrounded before shaping, to get correct lighting
}
select {
case err := <-errChan:
return err
default:
}
for j := int32(0); j < int32(b.Max.Y); j += 16 {
chunkZ := j >> 4
for i := int32(0); i < int32(b.Max.X); i += 16 {
chunkX := i >> 4
var totalHeight int32
ot := ts[0]
ts = ts[1:]
oy, _ := level.GetHeight(i, j)
for x := i; x < i+16; x++ {
for z := j; z < j+16; z++ {
if biomes != nil {
level.SetBiome(x, z, g.Biomes.Values[biomes.ColorIndexAt(int(x), int(z))])
}
h := int32(height.GrayAt(int(x), int(z)).Y)
totalHeight += h
wl := int32(water.GrayAt(int(x), int(z)).Y)
y := oy
if h > y {
y = h
}
if wl > y {
y = wl
}
for ; y > h && y > wl; y-- {
level.SetBlock(x, y, z, minecraft.Block{})
}
if plants != nil {
p := g.Plants.Blocks[plants.ColorIndexAt(int(x), int(z))]
py := int32(1)
for ; py <= int32(p.Level); py++ {
level.SetBlock(x, y+py, z, p.Base)
}
level.SetBlock(x, y+py, z, p.Top)
}
for ; y > h; y-- {
level.SetBlock(x, y, z, minecraft.Block{ID: 9})
}
t := terrain.ColorIndexAt(int(x), int(z))
tb := g.Terrain.Blocks[t]
for ; y > h-int32(tb.Level); y-- {
level.SetBlock(x, y, z, tb.Top)
}
if t != ot {
h = 0
} else {
h = oy
}
for ; y >= h; y-- {
level.SetBlock(x, y, z, tb.Base)
}
}
}
c <- paint{
color.Alpha{uint8(totalHeight >> 8)},
chunkX, chunkZ,
}
select {
case p, ok := <-proceed:
if ok {
ts = append(ts, p)
}
case err := <-errChan:
return err
}
}
}
return nil
}
func (e *encoder) writeImageBlock(pm *image.Paletted, delay int, disposal byte) {
if e.err != nil {
return
}
if len(pm.Palette) == 0 {
e.err = errors.New("gif: cannot encode image block with empty palette")
return
}
b := pm.Bounds()
if b.Min.X < 0 || b.Max.X >= 1<<16 || b.Min.Y < 0 || b.Max.Y >= 1<<16 {
e.err = errors.New("gif: image block is too large to encode")
return
}
if !b.In(image.Rectangle{Max: image.Point{e.g.Config.Width, e.g.Config.Height}}) {
e.err = errors.New("gif: image block is out of bounds")
return
}
transparentIndex := -1
for i, c := range pm.Palette {
if _, _, _, a := c.RGBA(); a == 0 {
transparentIndex = i
break
}
}
if delay > 0 || disposal != 0 || transparentIndex != -1 {
e.buf[0] = sExtension // Extension Introducer.
e.buf[1] = gcLabel // Graphic Control Label.
e.buf[2] = gcBlockSize // Block Size.
if transparentIndex != -1 {
e.buf[3] = 0x01 | disposal<<2
} else {
e.buf[3] = 0x00 | disposal<<2
}
writeUint16(e.buf[4:6], uint16(delay)) // Delay Time (1/100ths of a second)
// Transparent color index.
if transparentIndex != -1 {
e.buf[6] = uint8(transparentIndex)
} else {
e.buf[6] = 0x00
}
e.buf[7] = 0x00 // Block Terminator.
e.write(e.buf[:8])
}
e.buf[0] = sImageDescriptor
writeUint16(e.buf[1:3], uint16(b.Min.X))
writeUint16(e.buf[3:5], uint16(b.Min.Y))
writeUint16(e.buf[5:7], uint16(b.Dx()))
writeUint16(e.buf[7:9], uint16(b.Dy()))
e.write(e.buf[:9])
paddedSize := log2(len(pm.Palette)) // Size of Local Color Table: 2^(1+n).
ct := encodeColorTable(e.localColorTable[:], pm.Palette, paddedSize)
if ct != e.globalCT || !bytes.Equal(e.globalColorTable[:ct], e.localColorTable[:ct]) {
// Use a local color table.
e.writeByte(fColorTable | uint8(paddedSize))
e.write(e.localColorTable[:ct])
} else {
// Use the global color table.
e.writeByte(0)
}
litWidth := paddedSize + 1
if litWidth < 2 {
litWidth = 2
}
e.writeByte(uint8(litWidth)) // LZW Minimum Code Size.
lzww := lzw.NewWriter(blockWriter{e: e}, lzw.LSB, litWidth)
if dx := b.Dx(); dx == pm.Stride {
_, e.err = lzww.Write(pm.Pix)
if e.err != nil {
lzww.Close()
return
}
} else {
for i, y := 0, b.Min.Y; y < b.Max.Y; i, y = i+pm.Stride, y+1 {
_, e.err = lzww.Write(pm.Pix[i : i+dx])
if e.err != nil {
lzww.Close()
return
}
}
}
lzww.Close()
e.writeByte(0x00) // Block Terminator.
}
func writeImage(w io.Writer, m image.Image, ct uint8) os.Error {
zw, err := zlib.NewDeflater(w)
if err != nil {
return err
}
defer zw.Close()
bpp := 0 // Bytes per pixel.
var paletted *image.Paletted
switch ct {
case ctTrueColor:
bpp = 3
case ctPaletted:
bpp = 1
paletted = m.(*image.Paletted)
case ctTrueColorAlpha:
bpp = 4
}
// cr[*] and pr are the bytes for the current and previous row.
// cr[0] is unfiltered (or equivalently, filtered with the ftNone filter).
// cr[ft], for non-zero filter types ft, are buffers for transforming cr[0] under the
// other PNG filter types. These buffers are allocated once and re-used for each row.
// The +1 is for the per-row filter type, which is at cr[*][0].
var cr [nFilter][]uint8
for i := 0; i < len(cr); i++ {
cr[i] = make([]uint8, 1+bpp*m.Width())
cr[i][0] = uint8(i)
}
pr := make([]uint8, 1+bpp*m.Width())
for y := 0; y < m.Height(); y++ {
// Convert from colors to bytes.
switch ct {
case ctTrueColor:
for x := 0; x < m.Width(); x++ {
// We have previously verified that the alpha value is fully opaque.
r, g, b, _ := m.At(x, y).RGBA()
cr[0][3*x+1] = uint8(r >> 24)
cr[0][3*x+2] = uint8(g >> 24)
cr[0][3*x+3] = uint8(b >> 24)
}
case ctPaletted:
for x := 0; x < m.Width(); x++ {
cr[0][x+1] = paletted.ColorIndexAt(x, y)
}
case ctTrueColorAlpha:
// Convert from image.Image (which is alpha-premultiplied) to PNG's non-alpha-premultiplied.
for x := 0; x < m.Width(); x++ {
c := image.NRGBAColorModel.Convert(m.At(x, y)).(image.NRGBAColor)
cr[0][4*x+1] = c.R
cr[0][4*x+2] = c.G
cr[0][4*x+3] = c.B
cr[0][4*x+4] = c.A
}
}
// Apply the filter.
f := filter(cr[0:nFilter], pr, bpp)
// Write the compressed bytes.
_, err = zw.Write(cr[f])
if err != nil {
return err
}
// The current row for y is the previous row for y+1.
pr, cr[0] = cr[0], pr
}
return nil
}
func (d *decoder) idatReader(idat io.Reader) os.Error {
r, err := zlib.NewInflater(idat)
if err != nil {
return err
}
defer r.Close()
bpp := 0 // Bytes per pixel.
maxPalette := uint8(0)
var (
rgba *image.RGBA
nrgba *image.NRGBA
paletted *image.Paletted
)
switch d.colorType {
case ctTrueColor:
bpp = 3
rgba = d.image.(*image.RGBA)
case ctPaletted:
bpp = 1
paletted = d.image.(*image.Paletted)
maxPalette = uint8(len(paletted.Palette) - 1)
case ctTrueColorAlpha:
bpp = 4
nrgba = d.image.(*image.NRGBA)
}
// cr and pr are the bytes for the current and previous row.
// The +1 is for the per-row filter type, which is at cr[0].
cr := make([]uint8, 1+bpp*d.width)
pr := make([]uint8, 1+bpp*d.width)
for y := 0; y < d.height; y++ {
// Read the decompressed bytes.
_, err := io.ReadFull(r, cr)
if err != nil {
return err
}
// Apply the filter.
cdat := cr[1:]
pdat := pr[1:]
switch cr[0] {
case ftNone:
// No-op.
case ftSub:
for i := bpp; i < len(cdat); i++ {
cdat[i] += cdat[i-bpp]
}
case ftUp:
for i := 0; i < len(cdat); i++ {
cdat[i] += pdat[i]
}
case ftAverage:
for i := 0; i < bpp; i++ {
cdat[i] += pdat[i] / 2
}
for i := bpp; i < len(cdat); i++ {
cdat[i] += uint8((int(cdat[i-bpp]) + int(pdat[i])) / 2)
}
case ftPaeth:
for i := 0; i < bpp; i++ {
cdat[i] += paeth(0, pdat[i], 0)
}
for i := bpp; i < len(cdat); i++ {
cdat[i] += paeth(cdat[i-bpp], pdat[i], pdat[i-bpp])
}
default:
return FormatError("bad filter type")
}
// Convert from bytes to colors.
switch d.colorType {
case ctTrueColor:
for x := 0; x < d.width; x++ {
rgba.Set(x, y, image.RGBAColor{cdat[3*x+0], cdat[3*x+1], cdat[3*x+2], 0xff})
}
case ctPaletted:
for x := 0; x < d.width; x++ {
if cdat[x] > maxPalette {
return FormatError("palette index out of range")
}
paletted.SetColorIndex(x, y, cdat[x])
}
case ctTrueColorAlpha:
for x := 0; x < d.width; x++ {
nrgba.Set(x, y, image.NRGBAColor{cdat[4*x+0], cdat[4*x+1], cdat[4*x+2], cdat[4*x+3]})
}
}
// The current row for y is the previous row for y+1.
pr, cr = cr, pr
}
return nil
}
// readImagePass reads a single image pass, sized according to the pass number.
func (d *decoder) readImagePass(r io.Reader, pass int, allocateOnly bool) (image.Image, error) {
var bitsPerPixel int = 0
pixOffset := 0
var (
gray *image.Gray
rgba *image.RGBA
paletted *image.Paletted
nrgba *image.NRGBA
gray16 *image.Gray16
rgba64 *image.RGBA64
nrgba64 *image.NRGBA64
img image.Image
)
width, height := d.width, d.height
if d.interlace == itAdam7 && !allocateOnly {
p := interlacing[pass]
// Add the multiplication factor and subtract one, effectively rounding up.
width = (width - p.xOffset + p.xFactor - 1) / p.xFactor
height = (height - p.yOffset + p.yFactor - 1) / p.yFactor
// A PNG image can't have zero width or height, but for an interlaced
// image, an individual pass might have zero width or height. If so, we
// shouldn't even read a per-row filter type byte, so return early.
if width == 0 || height == 0 {
return nil, nil
}
}
switch d.cb {
case cbG1, cbG2, cbG4, cbG8:
bitsPerPixel = d.depth
gray = image.NewGray(image.Rect(0, 0, width, height))
img = gray
case cbGA8:
bitsPerPixel = 16
nrgba = image.NewNRGBA(image.Rect(0, 0, width, height))
img = nrgba
case cbTC8:
bitsPerPixel = 24
rgba = image.NewRGBA(image.Rect(0, 0, width, height))
img = rgba
case cbP1, cbP2, cbP4, cbP8:
bitsPerPixel = d.depth
paletted = image.NewPaletted(image.Rect(0, 0, width, height), d.palette)
img = paletted
case cbTCA8:
bitsPerPixel = 32
nrgba = image.NewNRGBA(image.Rect(0, 0, width, height))
img = nrgba
case cbG16:
bitsPerPixel = 16
gray16 = image.NewGray16(image.Rect(0, 0, width, height))
img = gray16
case cbGA16:
bitsPerPixel = 32
nrgba64 = image.NewNRGBA64(image.Rect(0, 0, width, height))
img = nrgba64
case cbTC16:
bitsPerPixel = 48
rgba64 = image.NewRGBA64(image.Rect(0, 0, width, height))
img = rgba64
case cbTCA16:
bitsPerPixel = 64
nrgba64 = image.NewNRGBA64(image.Rect(0, 0, width, height))
img = nrgba64
}
if allocateOnly {
return img, nil
}
bytesPerPixel := (bitsPerPixel + 7) / 8
// The +1 is for the per-row filter type, which is at cr[0].
rowSize := 1 + (bitsPerPixel*width+7)/8
// cr and pr are the bytes for the current and previous row.
cr := make([]uint8, rowSize)
pr := make([]uint8, rowSize)
for y := 0; y < height; y++ {
// Read the decompressed bytes.
_, err := io.ReadFull(r, cr)
if err != nil {
if err == io.EOF || err == io.ErrUnexpectedEOF {
return nil, FormatError("not enough pixel data")
}
return nil, err
}
// Apply the filter.
cdat := cr[1:]
pdat := pr[1:]
switch cr[0] {
case ftNone:
// No-op.
case ftSub:
for i := bytesPerPixel; i < len(cdat); i++ {
cdat[i] += cdat[i-bytesPerPixel]
}
case ftUp:
for i, p := range pdat {
cdat[i] += p
}
case ftAverage:
// The first column has no column to the left of it, so it is a
// special case. We know that the first column exists because we
// check above that width != 0, and so len(cdat) != 0.
for i := 0; i < bytesPerPixel; i++ {
cdat[i] += pdat[i] / 2
}
for i := bytesPerPixel; i < len(cdat); i++ {
cdat[i] += uint8((int(cdat[i-bytesPerPixel]) + int(pdat[i])) / 2)
}
case ftPaeth:
filterPaeth(cdat, pdat, bytesPerPixel)
default:
return nil, FormatError("bad filter type")
}
// Convert from bytes to colors.
switch d.cb {
case cbG1:
for x := 0; x < width; x += 8 {
b := cdat[x/8]
for x2 := 0; x2 < 8 && x+x2 < width; x2++ {
gray.SetGray(x+x2, y, color.Gray{(b >> 7) * 0xff})
b <<= 1
}
}
case cbG2:
for x := 0; x < width; x += 4 {
b := cdat[x/4]
for x2 := 0; x2 < 4 && x+x2 < width; x2++ {
gray.SetGray(x+x2, y, color.Gray{(b >> 6) * 0x55})
b <<= 2
}
}
case cbG4:
for x := 0; x < width; x += 2 {
b := cdat[x/2]
for x2 := 0; x2 < 2 && x+x2 < width; x2++ {
gray.SetGray(x+x2, y, color.Gray{(b >> 4) * 0x11})
b <<= 4
}
}
case cbG8:
copy(gray.Pix[pixOffset:], cdat)
pixOffset += gray.Stride
case cbGA8:
for x := 0; x < width; x++ {
ycol := cdat[2*x+0]
nrgba.SetNRGBA(x, y, color.NRGBA{ycol, ycol, ycol, cdat[2*x+1]})
}
case cbTC8:
pix, i, j := rgba.Pix, pixOffset, 0
for x := 0; x < width; x++ {
pix[i+0] = cdat[j+0]
pix[i+1] = cdat[j+1]
pix[i+2] = cdat[j+2]
pix[i+3] = 0xff
i += 4
j += 3
}
pixOffset += rgba.Stride
case cbP1:
for x := 0; x < width; x += 8 {
b := cdat[x/8]
for x2 := 0; x2 < 8 && x+x2 < width; x2++ {
idx := b >> 7
if len(paletted.Palette) <= int(idx) {
paletted.Palette = paletted.Palette[:int(idx)+1]
}
paletted.SetColorIndex(x+x2, y, idx)
b <<= 1
}
}
case cbP2:
for x := 0; x < width; x += 4 {
b := cdat[x/4]
for x2 := 0; x2 < 4 && x+x2 < width; x2++ {
idx := b >> 6
if len(paletted.Palette) <= int(idx) {
paletted.Palette = paletted.Palette[:int(idx)+1]
}
paletted.SetColorIndex(x+x2, y, idx)
b <<= 2
}
}
case cbP4:
for x := 0; x < width; x += 2 {
b := cdat[x/2]
for x2 := 0; x2 < 2 && x+x2 < width; x2++ {
idx := b >> 4
if len(paletted.Palette) <= int(idx) {
paletted.Palette = paletted.Palette[:int(idx)+1]
}
paletted.SetColorIndex(x+x2, y, idx)
b <<= 4
}
}
case cbP8:
if len(paletted.Palette) != 255 {
for x := 0; x < width; x++ {
if len(paletted.Palette) <= int(cdat[x]) {
paletted.Palette = paletted.Palette[:int(cdat[x])+1]
}
}
}
copy(paletted.Pix[pixOffset:], cdat)
pixOffset += paletted.Stride
case cbTCA8:
copy(nrgba.Pix[pixOffset:], cdat)
pixOffset += nrgba.Stride
case cbG16:
for x := 0; x < width; x++ {
ycol := uint16(cdat[2*x+0])<<8 | uint16(cdat[2*x+1])
gray16.SetGray16(x, y, color.Gray16{ycol})
}
case cbGA16:
for x := 0; x < width; x++ {
ycol := uint16(cdat[4*x+0])<<8 | uint16(cdat[4*x+1])
acol := uint16(cdat[4*x+2])<<8 | uint16(cdat[4*x+3])
nrgba64.SetNRGBA64(x, y, color.NRGBA64{ycol, ycol, ycol, acol})
}
case cbTC16:
for x := 0; x < width; x++ {
rcol := uint16(cdat[6*x+0])<<8 | uint16(cdat[6*x+1])
gcol := uint16(cdat[6*x+2])<<8 | uint16(cdat[6*x+3])
bcol := uint16(cdat[6*x+4])<<8 | uint16(cdat[6*x+5])
rgba64.SetRGBA64(x, y, color.RGBA64{rcol, gcol, bcol, 0xffff})
}
case cbTCA16:
for x := 0; x < width; x++ {
rcol := uint16(cdat[8*x+0])<<8 | uint16(cdat[8*x+1])
gcol := uint16(cdat[8*x+2])<<8 | uint16(cdat[8*x+3])
bcol := uint16(cdat[8*x+4])<<8 | uint16(cdat[8*x+5])
acol := uint16(cdat[8*x+6])<<8 | uint16(cdat[8*x+7])
nrgba64.SetNRGBA64(x, y, color.NRGBA64{rcol, gcol, bcol, acol})
}
}
// The current row for y is the previous row for y+1.
pr, cr = cr, pr
}
return img, nil
}
func (w *wire) draw(img *image.Paletted, colorIndex uint8) {
for _, pixel := range w.pixels {
img.SetColorIndex(pixel.X, pixel.Y, colorIndex)
}
}
// An approximation of the sng command-line tool.
func sng(w io.WriteCloser, filename string, png image.Image) {
defer w.Close()
bounds := png.Bounds()
cm := png.ColorModel()
var bitdepth int
switch cm {
case color.RGBAModel, color.NRGBAModel, color.AlphaModel, color.GrayModel:
bitdepth = 8
default:
bitdepth = 16
}
cpm, _ := cm.(color.Palette)
var paletted *image.Paletted
if cpm != nil {
switch {
case len(cpm) <= 2:
bitdepth = 1
case len(cpm) <= 4:
bitdepth = 2
case len(cpm) <= 16:
bitdepth = 4
default:
bitdepth = 8
}
paletted = png.(*image.Paletted)
}
// Write the filename and IHDR.
io.WriteString(w, "#SNG: from "+filename+".png\nIHDR {\n")
fmt.Fprintf(w, " width: %d; height: %d; bitdepth: %d;\n", bounds.Dx(), bounds.Dy(), bitdepth)
switch {
case cm == color.RGBAModel, cm == color.RGBA64Model:
io.WriteString(w, " using color;\n")
case cm == color.NRGBAModel, cm == color.NRGBA64Model:
io.WriteString(w, " using color alpha;\n")
case cm == color.GrayModel, cm == color.Gray16Model:
io.WriteString(w, " using grayscale;\n")
case cpm != nil:
io.WriteString(w, " using color palette;\n")
default:
io.WriteString(w, "unknown PNG decoder color model\n")
}
io.WriteString(w, "}\n")
// We fake a gAMA output. The test files have a gAMA chunk but the go PNG parser ignores it
// (the PNG spec section 11.3 says "Ancillary chunks may be ignored by a decoder").
io.WriteString(w, "gAMA {1.0000}\n")
// Write the PLTE and tRNS (if applicable).
if cpm != nil {
lastAlpha := -1
io.WriteString(w, "PLTE {\n")
for i, c := range cpm {
r, g, b, a := c.RGBA()
if a != 0xffff {
lastAlpha = i
}
r >>= 8
g >>= 8
b >>= 8
fmt.Fprintf(w, " (%3d,%3d,%3d) # rgb = (0x%02x,0x%02x,0x%02x)\n", r, g, b, r, g, b)
}
io.WriteString(w, "}\n")
if lastAlpha != -1 {
io.WriteString(w, "tRNS {\n")
for i := 0; i <= lastAlpha; i++ {
_, _, _, a := cpm[i].RGBA()
a >>= 8
fmt.Fprintf(w, " %d", a)
}
io.WriteString(w, "}\n")
}
}
// Write the IMAGE.
io.WriteString(w, "IMAGE {\n pixels hex\n")
for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
switch {
case cm == color.GrayModel:
for x := bounds.Min.X; x < bounds.Max.X; x++ {
gray := png.At(x, y).(color.Gray)
fmt.Fprintf(w, "%02x", gray.Y)
}
case cm == color.Gray16Model:
for x := bounds.Min.X; x < bounds.Max.X; x++ {
gray16 := png.At(x, y).(color.Gray16)
fmt.Fprintf(w, "%04x ", gray16.Y)
}
case cm == color.RGBAModel:
for x := bounds.Min.X; x < bounds.Max.X; x++ {
rgba := png.At(x, y).(color.RGBA)
fmt.Fprintf(w, "%02x%02x%02x ", rgba.R, rgba.G, rgba.B)
}
case cm == color.RGBA64Model:
for x := bounds.Min.X; x < bounds.Max.X; x++ {
rgba64 := png.At(x, y).(color.RGBA64)
fmt.Fprintf(w, "%04x%04x%04x ", rgba64.R, rgba64.G, rgba64.B)
}
case cm == color.NRGBAModel:
for x := bounds.Min.X; x < bounds.Max.X; x++ {
nrgba := png.At(x, y).(color.NRGBA)
fmt.Fprintf(w, "%02x%02x%02x%02x ", nrgba.R, nrgba.G, nrgba.B, nrgba.A)
}
case cm == color.NRGBA64Model:
for x := bounds.Min.X; x < bounds.Max.X; x++ {
nrgba64 := png.At(x, y).(color.NRGBA64)
fmt.Fprintf(w, "%04x%04x%04x%04x ", nrgba64.R, nrgba64.G, nrgba64.B, nrgba64.A)
}
case cpm != nil:
var b, c int
for x := bounds.Min.X; x < bounds.Max.X; x++ {
b = b<<uint(bitdepth) | int(paletted.ColorIndexAt(x, y))
c++
if c == 8/bitdepth {
fmt.Fprintf(w, "%02x", b)
b = 0
c = 0
}
}
}
io.WriteString(w, "\n")
}
io.WriteString(w, "}\n")
}
func NewSimulation(img *image.Paletted) *Simulation {
size := img.Bounds().Size()
groups := make(map[*group]struct{}, 0)
matrix := newBucketMatrix(size.X, size.Y)
for y := 0; y < size.Y; y++ {
for x := 0; x < size.X; x++ {
c := img.ColorIndexAt(x, y)
if c > 0 && c <= maxCharge+1 {
topLeftBucket := matrix.get(x-1, y-1)
topBucket := matrix.get(x, y-1)
leftBucket := matrix.get(x-1, y)
var currentBucket *bucket
switch {
case nil == topBucket && nil == leftBucket:
currentBucket = newBucket()
groups[currentBucket.group] = struct{}{}
case nil == topBucket && nil != leftBucket:
currentBucket = leftBucket
case (nil != topBucket && nil == leftBucket) ||
topBucket == leftBucket ||
topBucket.group == leftBucket.group:
currentBucket = topBucket
default:
currentBucket = topBucket
delete(groups, topBucket.group)
topBucket.group.moveBucketsTo(leftBucket.group)
}
if nil != topLeftBucket && nil != topBucket && nil != leftBucket {
currentBucket.group.wire.isPowerSource = true
}
matrix.set(x, y, currentBucket)
currentBucket.addPixel(image.Point{x, y})
}
}
}
for y := 0; y < size.Y; y++ {
for x := 0; x < size.X; x++ {
if nil != matrix.get(x, y) {
continue
}
topBucket := matrix.get(x, y-1)
topRightBucket := matrix.get(x+1, y-1)
rightBucket := matrix.get(x+1, y)
bottomRightBucket := matrix.get(x+1, y+1)
bottomBucket := matrix.get(x, y+1)
bottomLeftBucket := matrix.get(x-1, y+1)
leftBucket := matrix.get(x-1, y)
topLeftBucket := matrix.get(x-1, y-1)
if nil == topLeftBucket && nil == topRightBucket && nil == bottomLeftBucket && nil == bottomRightBucket &&
nil != topBucket && nil != rightBucket && nil != bottomBucket && nil != leftBucket {
delete(groups, topBucket.group)
topBucket.group.moveBucketsTo(bottomBucket.group)
delete(groups, leftBucket.group)
leftBucket.group.moveBucketsTo(rightBucket.group)
}
}
}
transistors := make([]*transistor, 0)
for y := 0; y < size.Y; y++ {
for x := 0; x < size.X; x++ {
if nil != matrix.get(x, y) {
continue
}
topBucket := matrix.get(x, y-1)
topRightBucket := matrix.get(x+1, y-1)
rightBucket := matrix.get(x+1, y)
bottomRightBucket := matrix.get(x+1, y+1)
bottomBucket := matrix.get(x, y+1)
bottomLeftBucket := matrix.get(x-1, y+1)
leftBucket := matrix.get(x-1, y)
topLeftBucket := matrix.get(x-1, y-1)
switch {
case nil == bottomLeftBucket && nil == bottomRightBucket &&
nil == topBucket && nil != rightBucket && nil != bottomBucket && nil != leftBucket:
transistors = append(transistors,
newTransistor(image.Point{x, y}, bottomBucket.group.wire, rightBucket.group.wire, leftBucket.group.wire))
case nil == bottomLeftBucket && nil == topLeftBucket &&
nil != topBucket && nil == rightBucket && nil != bottomBucket && nil != leftBucket:
transistors = append(transistors,
newTransistor(image.Point{x, y}, leftBucket.group.wire, topBucket.group.wire, bottomBucket.group.wire))
case nil == topLeftBucket && nil == topRightBucket &&
nil != topBucket && nil != rightBucket && nil == bottomBucket && nil != leftBucket:
transistors = append(transistors,
newTransistor(image.Point{x, y}, topBucket.group.wire, rightBucket.group.wire, leftBucket.group.wire))
case nil == bottomRightBucket && nil == topRightBucket &&
nil != topBucket && nil != rightBucket && nil != bottomBucket && nil == leftBucket:
transistors = append(transistors,
newTransistor(image.Point{x, y}, rightBucket.group.wire, topBucket.group.wire, bottomBucket.group.wire))
}
}
}
wires := make([]*wire, len(groups))
wireStates := make([]wireState, len(groups))
i := 0
for k := range groups {
k.wire.index = i
wires[i] = k.wire
var charge uint8
if k.wire.isPowerSource {
charge = maxCharge
} else {
charge = 0
}
wireStates[i] = wireState{charge, k.wire}
i++
}
return &Simulation{&circuit{wires: wires, transistors: transistors}, wireStates}
}
// decode reads a GIF image from r and stores the result in d.
func (d *decoder) decode(r io.Reader, configOnly bool) error {
// Add buffering if r does not provide ReadByte.
if rr, ok := r.(reader); ok {
d.r = rr
} else {
d.r = bufio.NewReader(r)
}
err := d.readHeaderAndScreenDescriptor()
if err != nil {
return err
}
if configOnly {
return nil
}
if d.headerFields&fColorMapFollows != 0 {
if d.globalColorMap, err = d.readColorMap(); err != nil {
return err
}
}
Loop:
for err == nil {
var c byte
c, err = d.r.ReadByte()
if err == io.EOF {
break
}
switch c {
case sExtension:
err = d.readExtension()
case sImageDescriptor:
var m *image.Paletted
m, err = d.newImageFromDescriptor()
if err != nil {
break
}
if d.imageFields&fColorMapFollows != 0 {
m.Palette, err = d.readColorMap()
if err != nil {
break
}
// TODO: do we set transparency in this map too? That would be
// d.setTransparency(m.Palette)
} else {
m.Palette = d.globalColorMap
}
var litWidth uint8
litWidth, err = d.r.ReadByte()
if err != nil {
return err
}
if litWidth < 2 || litWidth > 8 {
return fmt.Errorf("gif: pixel size in decode out of range: %d", litWidth)
}
// A wonderfully Go-like piece of magic.
lzwr := lzw.NewReader(&blockReader{r: d.r}, lzw.LSB, int(litWidth))
if _, err = io.ReadFull(lzwr, m.Pix); err != nil {
break
}
// There should be a "0" block remaining; drain that.
c, err = d.r.ReadByte()
if err != nil {
return err
}
if c != 0 {
return errors.New("gif: extra data after image")
}
// Undo the interlacing if necessary.
if d.imageFields&ifInterlace != 0 {
uninterlace(m)
}
d.image = append(d.image, m)
d.delay = append(d.delay, d.delayTime)
d.delayTime = 0 // TODO: is this correct, or should we hold on to the value?
case sTrailer:
break Loop
default:
err = fmt.Errorf("gif: unknown block type: 0x%.2x", c)
}
}
if err != nil {
return err
}
if len(d.image) == 0 {
return io.ErrUnexpectedEOF
}
return nil
}
// An approximation of the sng command-line tool.
func sng(w io.WriteCloser, filename string, png image.Image) {
defer w.Close()
bounds := png.Bounds()
cm := png.ColorModel()
var bitdepth int
switch cm {
case color.RGBAModel, color.NRGBAModel, color.AlphaModel, color.GrayModel:
bitdepth = 8
default:
bitdepth = 16
}
cpm, _ := cm.(color.Palette)
var paletted *image.Paletted
if cpm != nil {
switch {
case len(cpm) <= 2:
bitdepth = 1
case len(cpm) <= 4:
bitdepth = 2
case len(cpm) <= 16:
bitdepth = 4
default:
bitdepth = 8
}
paletted = png.(*image.Paletted)
}
// Write the filename and IHDR.
io.WriteString(w, "#SNG: from "+filename+".png\nIHDR {\n")
fmt.Fprintf(w, " width: %d; height: %d; bitdepth: %d;\n", bounds.Dx(), bounds.Dy(), bitdepth)
if s, ok := fakeIHDRUsings[filename]; ok {
io.WriteString(w, s)
} else {
switch {
case cm == color.RGBAModel, cm == color.RGBA64Model:
io.WriteString(w, " using color;\n")
case cm == color.NRGBAModel, cm == color.NRGBA64Model:
io.WriteString(w, " using color alpha;\n")
case cm == color.GrayModel, cm == color.Gray16Model:
io.WriteString(w, " using grayscale;\n")
case cpm != nil:
io.WriteString(w, " using color palette;\n")
default:
io.WriteString(w, "unknown PNG decoder color model\n")
}
}
io.WriteString(w, "}\n")
// We fake a gAMA chunk. The test files have a gAMA chunk but the go PNG
// parser ignores it (the PNG spec section 11.3 says "Ancillary chunks may
// be ignored by a decoder").
if s, ok := fakegAMAs[filename]; ok {
io.WriteString(w, s)
} else {
io.WriteString(w, "gAMA {1.0000}\n")
}
// Write the PLTE and tRNS (if applicable).
useTransparent := false
if cpm != nil {
lastAlpha := -1
io.WriteString(w, "PLTE {\n")
for i, c := range cpm {
var r, g, b, a uint8
switch c := c.(type) {
case color.RGBA:
r, g, b, a = c.R, c.G, c.B, 0xff
case color.NRGBA:
r, g, b, a = c.R, c.G, c.B, c.A
default:
panic("unknown palette color type")
}
if a != 0xff {
lastAlpha = i
}
fmt.Fprintf(w, " (%3d,%3d,%3d) # rgb = (0x%02x,0x%02x,0x%02x)\n", r, g, b, r, g, b)
}
io.WriteString(w, "}\n")
if s, ok := fakebKGDs[filename]; ok {
io.WriteString(w, s)
}
if lastAlpha != -1 {
io.WriteString(w, "tRNS {\n")
for i := 0; i <= lastAlpha; i++ {
_, _, _, a := cpm[i].RGBA()
a >>= 8
fmt.Fprintf(w, " %d", a)
}
io.WriteString(w, "}\n")
}
} else if strings.HasPrefix(filename, "ft") {
if s, ok := fakebKGDs[filename]; ok {
io.WriteString(w, s)
}
// We fake a tRNS chunk. The test files' grayscale and truecolor
// transparent images all have their top left corner transparent.
switch c := png.At(0, 0).(type) {
case color.NRGBA:
if c.A == 0 {
useTransparent = true
io.WriteString(w, "tRNS {\n")
switch filename {
case "ftbbn0g01", "ftbbn0g02", "ftbbn0g04":
// The standard image package doesn't have a "gray with
// alpha" type. Instead, we use an image.NRGBA.
fmt.Fprintf(w, " gray: %d;\n", c.R)
default:
fmt.Fprintf(w, " red: %d; green: %d; blue: %d;\n", c.R, c.G, c.B)
}
io.WriteString(w, "}\n")
}
case color.NRGBA64:
if c.A == 0 {
useTransparent = true
io.WriteString(w, "tRNS {\n")
switch filename {
case "ftbwn0g16":
// The standard image package doesn't have a "gray16 with
// alpha" type. Instead, we use an image.NRGBA64.
fmt.Fprintf(w, " gray: %d;\n", c.R)
default:
fmt.Fprintf(w, " red: %d; green: %d; blue: %d;\n", c.R, c.G, c.B)
}
io.WriteString(w, "}\n")
}
}
}
// Write the IMAGE.
io.WriteString(w, "IMAGE {\n pixels hex\n")
for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
switch {
case cm == color.GrayModel:
for x := bounds.Min.X; x < bounds.Max.X; x++ {
gray := png.At(x, y).(color.Gray)
fmt.Fprintf(w, "%02x", gray.Y)
}
case cm == color.Gray16Model:
for x := bounds.Min.X; x < bounds.Max.X; x++ {
gray16 := png.At(x, y).(color.Gray16)
fmt.Fprintf(w, "%04x ", gray16.Y)
}
case cm == color.RGBAModel:
for x := bounds.Min.X; x < bounds.Max.X; x++ {
rgba := png.At(x, y).(color.RGBA)
fmt.Fprintf(w, "%02x%02x%02x ", rgba.R, rgba.G, rgba.B)
}
case cm == color.RGBA64Model:
for x := bounds.Min.X; x < bounds.Max.X; x++ {
rgba64 := png.At(x, y).(color.RGBA64)
fmt.Fprintf(w, "%04x%04x%04x ", rgba64.R, rgba64.G, rgba64.B)
}
case cm == color.NRGBAModel:
for x := bounds.Min.X; x < bounds.Max.X; x++ {
nrgba := png.At(x, y).(color.NRGBA)
switch filename {
case "ftbbn0g01", "ftbbn0g02", "ftbbn0g04":
fmt.Fprintf(w, "%02x", nrgba.R)
default:
if useTransparent {
fmt.Fprintf(w, "%02x%02x%02x ", nrgba.R, nrgba.G, nrgba.B)
} else {
fmt.Fprintf(w, "%02x%02x%02x%02x ", nrgba.R, nrgba.G, nrgba.B, nrgba.A)
}
}
}
case cm == color.NRGBA64Model:
for x := bounds.Min.X; x < bounds.Max.X; x++ {
nrgba64 := png.At(x, y).(color.NRGBA64)
switch filename {
case "ftbwn0g16":
fmt.Fprintf(w, "%04x ", nrgba64.R)
default:
if useTransparent {
fmt.Fprintf(w, "%04x%04x%04x ", nrgba64.R, nrgba64.G, nrgba64.B)
} else {
fmt.Fprintf(w, "%04x%04x%04x%04x ", nrgba64.R, nrgba64.G, nrgba64.B, nrgba64.A)
}
}
}
case cpm != nil:
var b, c int
for x := bounds.Min.X; x < bounds.Max.X; x++ {
b = b<<uint(bitdepth) | int(paletted.ColorIndexAt(x, y))
c++
if c == 8/bitdepth {
fmt.Fprintf(w, "%02x", b)
b = 0
c = 0
}
}
if c != 0 {
for c != 8/bitdepth {
b = b << uint(bitdepth)
c++
}
fmt.Fprintf(w, "%02x", b)
}
}
io.WriteString(w, "\n")
}
io.WriteString(w, "}\n")
}
// decode decodes the IDAT data into an image.
func (d *decoder) decode() (image.Image, error) {
r, err := zlib.NewReader(d)
if err != nil {
return nil, err
}
defer r.Close()
bitsPerPixel := 0
pixOffset := 0
var (
gray *image.Gray
rgba *image.RGBA
paletted *image.Paletted
nrgba *image.NRGBA
gray16 *image.Gray16
rgba64 *image.RGBA64
nrgba64 *image.NRGBA64
img image.Image
)
switch d.cb {
case cbG1, cbG2, cbG4, cbG8:
bitsPerPixel = d.depth
gray = image.NewGray(image.Rect(0, 0, d.width, d.height))
img = gray
case cbGA8:
bitsPerPixel = 16
nrgba = image.NewNRGBA(image.Rect(0, 0, d.width, d.height))
img = nrgba
case cbTC8:
bitsPerPixel = 24
rgba = image.NewRGBA(image.Rect(0, 0, d.width, d.height))
img = rgba
case cbP1, cbP2, cbP4, cbP8:
bitsPerPixel = d.depth
paletted = image.NewPaletted(image.Rect(0, 0, d.width, d.height), d.palette)
img = paletted
case cbTCA8:
bitsPerPixel = 32
nrgba = image.NewNRGBA(image.Rect(0, 0, d.width, d.height))
img = nrgba
case cbG16:
bitsPerPixel = 16
gray16 = image.NewGray16(image.Rect(0, 0, d.width, d.height))
img = gray16
case cbGA16:
bitsPerPixel = 32
nrgba64 = image.NewNRGBA64(image.Rect(0, 0, d.width, d.height))
img = nrgba64
case cbTC16:
bitsPerPixel = 48
rgba64 = image.NewRGBA64(image.Rect(0, 0, d.width, d.height))
img = rgba64
case cbTCA16:
bitsPerPixel = 64
nrgba64 = image.NewNRGBA64(image.Rect(0, 0, d.width, d.height))
img = nrgba64
}
bytesPerPixel := (bitsPerPixel + 7) / 8
// cr and pr are the bytes for the current and previous row.
// The +1 is for the per-row filter type, which is at cr[0].
cr := make([]uint8, 1+(bitsPerPixel*d.width+7)/8)
pr := make([]uint8, 1+(bitsPerPixel*d.width+7)/8)
for y := 0; y < d.height; y++ {
// Read the decompressed bytes.
_, err := io.ReadFull(r, cr)
if err != nil {
return nil, err
}
// Apply the filter.
cdat := cr[1:]
pdat := pr[1:]
switch cr[0] {
case ftNone:
// No-op.
case ftSub:
for i := bytesPerPixel; i < len(cdat); i++ {
cdat[i] += cdat[i-bytesPerPixel]
}
case ftUp:
for i, p := range pdat {
cdat[i] += p
}
case ftAverage:
for i := 0; i < bytesPerPixel; i++ {
cdat[i] += pdat[i] / 2
}
for i := bytesPerPixel; i < len(cdat); i++ {
cdat[i] += uint8((int(cdat[i-bytesPerPixel]) + int(pdat[i])) / 2)
}
case ftPaeth:
filterPaeth(cdat, pdat, bytesPerPixel)
default:
return nil, FormatError("bad filter type")
}
// Convert from bytes to colors.
switch d.cb {
case cbG1:
for x := 0; x < d.width; x += 8 {
b := cdat[x/8]
for x2 := 0; x2 < 8 && x+x2 < d.width; x2++ {
gray.SetGray(x+x2, y, color.Gray{(b >> 7) * 0xff})
b <<= 1
}
}
case cbG2:
for x := 0; x < d.width; x += 4 {
b := cdat[x/4]
for x2 := 0; x2 < 4 && x+x2 < d.width; x2++ {
gray.SetGray(x+x2, y, color.Gray{(b >> 6) * 0x55})
b <<= 2
}
}
case cbG4:
for x := 0; x < d.width; x += 2 {
b := cdat[x/2]
for x2 := 0; x2 < 2 && x+x2 < d.width; x2++ {
gray.SetGray(x+x2, y, color.Gray{(b >> 4) * 0x11})
b <<= 4
}
}
case cbG8:
copy(gray.Pix[pixOffset:], cdat)
pixOffset += gray.Stride
case cbGA8:
for x := 0; x < d.width; x++ {
ycol := cdat[2*x+0]
nrgba.SetNRGBA(x, y, color.NRGBA{ycol, ycol, ycol, cdat[2*x+1]})
}
case cbTC8:
pix, i, j := rgba.Pix, pixOffset, 0
for x := 0; x < d.width; x++ {
pix[i+0] = cdat[j+0]
pix[i+1] = cdat[j+1]
pix[i+2] = cdat[j+2]
pix[i+3] = 0xff
i += 4
j += 3
}
pixOffset += rgba.Stride
case cbP1:
for x := 0; x < d.width; x += 8 {
b := cdat[x/8]
for x2 := 0; x2 < 8 && x+x2 < d.width; x2++ {
idx := b >> 7
if len(paletted.Palette) <= int(idx) {
paletted.Palette = paletted.Palette[:int(idx)+1]
}
paletted.SetColorIndex(x+x2, y, idx)
b <<= 1
}
}
case cbP2:
for x := 0; x < d.width; x += 4 {
b := cdat[x/4]
for x2 := 0; x2 < 4 && x+x2 < d.width; x2++ {
idx := b >> 6
if len(paletted.Palette) <= int(idx) {
paletted.Palette = paletted.Palette[:int(idx)+1]
}
paletted.SetColorIndex(x+x2, y, idx)
b <<= 2
}
}
case cbP4:
for x := 0; x < d.width; x += 2 {
b := cdat[x/2]
for x2 := 0; x2 < 2 && x+x2 < d.width; x2++ {
idx := b >> 4
if len(paletted.Palette) <= int(idx) {
paletted.Palette = paletted.Palette[:int(idx)+1]
}
paletted.SetColorIndex(x+x2, y, idx)
b <<= 4
}
}
case cbP8:
if len(paletted.Palette) != 255 {
for x := 0; x < d.width; x++ {
if len(paletted.Palette) <= int(cdat[x]) {
paletted.Palette = paletted.Palette[:int(cdat[x])+1]
}
}
}
copy(paletted.Pix[pixOffset:], cdat)
pixOffset += paletted.Stride
case cbTCA8:
copy(nrgba.Pix[pixOffset:], cdat)
pixOffset += nrgba.Stride
case cbG16:
for x := 0; x < d.width; x++ {
ycol := uint16(cdat[2*x+0])<<8 | uint16(cdat[2*x+1])
gray16.SetGray16(x, y, color.Gray16{ycol})
}
case cbGA16:
for x := 0; x < d.width; x++ {
ycol := uint16(cdat[4*x+0])<<8 | uint16(cdat[4*x+1])
acol := uint16(cdat[4*x+2])<<8 | uint16(cdat[4*x+3])
nrgba64.SetNRGBA64(x, y, color.NRGBA64{ycol, ycol, ycol, acol})
}
case cbTC16:
for x := 0; x < d.width; x++ {
rcol := uint16(cdat[6*x+0])<<8 | uint16(cdat[6*x+1])
gcol := uint16(cdat[6*x+2])<<8 | uint16(cdat[6*x+3])
bcol := uint16(cdat[6*x+4])<<8 | uint16(cdat[6*x+5])
rgba64.SetRGBA64(x, y, color.RGBA64{rcol, gcol, bcol, 0xffff})
}
case cbTCA16:
for x := 0; x < d.width; x++ {
rcol := uint16(cdat[8*x+0])<<8 | uint16(cdat[8*x+1])
gcol := uint16(cdat[8*x+2])<<8 | uint16(cdat[8*x+3])
bcol := uint16(cdat[8*x+4])<<8 | uint16(cdat[8*x+5])
acol := uint16(cdat[8*x+6])<<8 | uint16(cdat[8*x+7])
nrgba64.SetNRGBA64(x, y, color.NRGBA64{rcol, gcol, bcol, acol})
}
}
// The current row for y is the previous row for y+1.
pr, cr = cr, pr
}
// Check for EOF, to verify the zlib checksum.
n, err := r.Read(pr[:1])
if err != io.EOF {
return nil, FormatError(err.Error())
}
if n != 0 || d.idatLength != 0 {
return nil, FormatError("too much pixel data")
}
return img, nil
}
func (e *encoder) writeImageBlock(pm *image.Paletted, delay, transparentIndex int) {
if e.err != nil {
return
}
if len(pm.Palette) == 0 {
e.err = errors.New("gif: cannot encode image block with empty palette")
return
}
b := pm.Bounds()
if b.Dx() >= 1<<16 || b.Dy() >= 1<<16 || b.Min.X < 0 || b.Min.X >= 1<<16 || b.Min.Y < 0 || b.Min.Y >= 1<<16 {
e.err = errors.New("gif: image block is too large to encode")
return
}
// -1 means unknown transparent index; -2 means definitely no transparent index.
if transparentIndex == -1 {
for i, c := range pm.Palette {
if _, _, _, a := c.RGBA(); a == 0 {
transparentIndex = i
break
}
}
transparentIndex = -2
}
if delay > 0 || transparentIndex >= 0 {
e.buf[0] = sExtension // Extension Introducer.
e.buf[1] = gcLabel // Graphic Control Label.
e.buf[2] = gcBlockSize // Block Size.
if transparentIndex >= 0 {
e.buf[3] = 0x01
} else {
e.buf[3] = 0x00
}
writeUint16(e.buf[4:6], uint16(delay)) // Delay Time (1/100ths of a second)
// Transparent color index.
if transparentIndex >= 0 {
e.buf[6] = uint8(transparentIndex)
} else {
e.buf[6] = 0x00
}
e.buf[7] = 0x00 // Block Terminator.
e.write(e.buf[:8])
}
e.buf[0] = sImageDescriptor
writeUint16(e.buf[1:3], uint16(b.Min.X))
writeUint16(e.buf[3:5], uint16(b.Min.Y))
writeUint16(e.buf[5:7], uint16(b.Dx()))
writeUint16(e.buf[7:9], uint16(b.Dy()))
e.write(e.buf[:9])
paddedSize := log2(len(pm.Palette)) // Size of Local Color Table: 2^(1+n).
// Interlacing is not supported.
e.writeByte(0x80 | uint8(paddedSize))
// Local Color Table.
e.writeColorTable(pm.Palette, paddedSize)
litWidth := paddedSize + 1
if litWidth < 2 {
litWidth = 2
}
e.writeByte(uint8(litWidth)) // LZW Minimum Code Size.
lzww := lzw.NewWriter(blockWriter{e: e}, lzw.LSB, litWidth)
_, e.err = lzww.Write(pm.Pix)
if e.err != nil {
lzww.Close()
return
}
lzww.Close()
e.writeByte(0x00) // Block Terminator.
}
