// decodeP6 reads a binary pixmap
func decodeP6(r *bufio.Reader, img draw.Image, width, height uint) {
var x, y, pix int
mask := byte(readU(r))
mul := 255 / mask
data := make([]byte, width*height*3)
space(r)
_, err := r.Read(data)
check(err)
for y = 0; y < int(height); y++ {
for x = 0; x < int(width); x++ {
img.Set(x, y, color.RGBA{
(data[pix] & mask) * mul,
(data[pix+1] & mask) * mul,
(data[pix+2] & mask) * mul,
0xff,
})
pix += 3
}
}
}
func line(img draw.Image, a, b image.Point, c color.Color) {
minx, maxx := minmax(a.X, b.X)
miny, maxy := minmax(a.Y, b.Y)
Δx := float64(b.X - a.X)
Δy := float64(b.Y - a.Y)
if maxx-minx > maxy-miny {
d := 1
if a.X > b.X {
d = -1
}
for x := 0; x != b.X-a.X+d; x += d {
y := int(float64(x) * Δy / Δx)
img.Set(a.X+x, a.Y+y, c)
}
} else {
d := 1
if a.Y > b.Y {
d = -1
}
for y := 0; y != b.Y-a.Y+d; y += d {
x := int(float64(y) * Δx / Δy)
img.Set(a.X+x, a.Y+y, c)
}
}
}
func warm(out, in draw.Image, opacity uint8, colors []color.Color) {
bounds := in.Bounds()
collen := float64(len(colors))
wg := sync.WaitGroup{}
wg.Add(bounds.Dx())
for x := bounds.Min.X; x < bounds.Max.X; x++ {
go func(x int) {
defer wg.Done()
for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
col := in.At(x, y)
_, _, _, alpha := col.RGBA()
percent := float64(alpha) / float64(0xffff)
var outcol color.Color
if percent == 0 {
outcol = color.Transparent
} else {
template := colors[int((collen-1)*(1.0-percent))]
tr, tg, tb, ta := template.RGBA()
ta /= 256
outalpha := uint8(float64(ta) *
(float64(opacity) / 256.0))
outcol = color.NRGBA{
uint8(tr / 256),
uint8(tg / 256),
uint8(tb / 256),
uint8(outalpha)}
}
out.Set(x, y, outcol)
}
}(x)
}
wg.Wait()
}
// http://en.wikipedia.org/wiki/Bresenham's_line_algorithm#Simplification
func line(x0, y0, x1, y1 int, c color.Color, img draw.Image) {
var dx = abs(x1 - x0)
var dy = abs(y1 - y0)
var err = dx - dy
var sx, sy = 1, 1
if x0 > x1 {
sx = -1
}
if y0 > y1 {
sy = -1
}
img.Set(x0, y0, c)
for x0 != x1 || y0 != y1 {
var e2 = 2 * err
if e2 > -dy {
err -= dy
x0 += sx
}
if e2 < dx {
err += dx
y0 += sy
}
img.Set(x0, y0, c)
}
}
// Transform applies the affine transform to src and produces dst.
func (a Affine) Transform(dst draw.Image, src image.Image, i interp.Interp) error {
if dst == nil {
return errors.New("graphics: dst is nil")
}
if src == nil {
return errors.New("graphics: src is nil")
}
// RGBA fast path.
dstRGBA, dstOk := dst.(*image.RGBA)
srcRGBA, srcOk := src.(*image.RGBA)
interpRGBA, interpOk := i.(interp.RGBA)
if dstOk && srcOk && interpOk {
return a.transformRGBA(dstRGBA, srcRGBA, interpRGBA)
}
srcb := src.Bounds()
b := dst.Bounds()
for y := b.Min.Y; y < b.Max.Y; y++ {
for x := b.Min.X; x < b.Max.X; x++ {
sx, sy := a.pt(x, y)
if inBounds(srcb, sx, sy) {
dst.Set(x, y, i.Interp(src, sx, sy))
}
}
}
return nil
}
func warm(out, in draw.Image, opacity uint8, colors []color.Color) {
draw.Draw(out, out.Bounds(), image.Transparent, image.ZP, draw.Src)
bounds := in.Bounds()
collen := float64(len(colors))
wg := &sync.WaitGroup{}
for x := bounds.Min.X; x < bounds.Max.X; x++ {
wg.Add(1)
go func(x int) {
defer wg.Done()
for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
col := in.At(x, y)
_, _, _, alpha := col.RGBA()
if alpha > 0 {
percent := float64(alpha) / float64(0xffff)
template := colors[int((collen-1)*(1.0-percent))]
tr, tg, tb, ta := template.RGBA()
ta /= 256
outalpha := uint8(float64(ta) *
(float64(opacity) / 256.0))
outcol := color.NRGBA{
uint8(tr / 256),
uint8(tg / 256),
uint8(tb / 256),
uint8(outalpha)}
out.Set(x, y, outcol)
}
}
}(x)
}
wg.Wait()
}
func Bresenham(img draw.Image, color color.Color, x0, y0, x1, y1 int) {
dx := abs(x1 - x0)
dy := abs(y1 - y0)
var sx, sy int
if x0 < x1 {
sx = 1
} else {
sx = -1
}
if y0 < y1 {
sy = 1
} else {
sy = -1
}
err := dx - dy
var e2 int
for {
img.Set(x0, y0, color)
if x0 == x1 && y0 == y1 {
return
}
e2 = 2 * err
if e2 > -dy {
err = err - dy
x0 = x0 + sx
}
if e2 < dx {
err = err + dx
y0 = y0 + sy
}
}
}
// 翻转函数，要求两个图像大小契合，act&1 == 0则左右翻转，否则垂直翻转。
func Overturn(dst draw.Image, src image.Image, act int) error {
var to func(int, int) (int, int)
sr := src.Bounds()
dr := dst.Bounds()
W := dr.Max.X - dr.Min.X
H := dr.Max.Y - dr.Min.Y
if H <= 0 || W <= 0 {
return errors.New("target image is empty or noncanonical")
}
if sr.Min.X >= sr.Max.X || sr.Min.Y >= sr.Max.Y {
return errors.New("source image is empty or noncanonical")
}
if sr.Max.X-sr.Min.X != W || sr.Max.Y-sr.Min.Y != H {
return errors.New("target and source must be same size!")
}
if act&1 == 0 {
to = func(x, y int) (int, int) {
return W - 1 - x, y
}
} else {
to = func(x, y int) (int, int) {
return x, H - 1 - y
}
}
for i := 0; i < W; i++ {
for j := 0; j < H; j++ {
x, y := to(i, j)
dst.Set(dr.Min.X+x, dr.Min.Y+y, src.At(sr.Min.X+i, sr.Min.Y+j))
}
}
return nil
}
// decodeP4 reads a binary bitmap
func decodeP4(r *bufio.Reader, img draw.Image, width, height uint) {
var x, y, bit int
bytes := int(math.Ceil((float64(width) / 8)))
bits := newBitset(uint(bytes) * height * 8)
pad := (bytes * 8) - int(width)
space(r)
_, err := r.Read(bits)
check(err)
for y = 0; y < int(height); y++ {
for x = 0; x < int(width); x++ {
if bits.Test(bit) {
img.Set(x, y, color.Alpha{0xff})
} else {
img.Set(x, y, color.Alpha{0x00})
}
bit++
}
bit += pad
}
}
func gennoise(screen draw.Image) {
for y := 0; y < 240; y++ {
for x := 0; x < 320; x++ {
screen.Set(x, y, <-randcol)
}
}
}
func testDrawRandom(p draw.Image) {
bd := p.Bounds()
for y, yEnd := bd.Min.Y, bd.Max.Y; y < yEnd; y++ {
for x, xEnd := bd.Min.X, bd.Max.X; x < xEnd; x++ {
p.Set(x, y, testRandomColor())
}
}
}
func imageConvert(src image.Image, dest draw.Image) draw.Image {
w, h := src.Bounds().Dx(), src.Bounds().Dy()
for y := 0; y < h; y += 1 {
for x := 0; x < w; x += 1 {
dest.Set(x, y, dest.ColorModel().Convert(src.At(x, y)))
}
}
return dest
}
// Apply the given color mapping to the specified image buffers.
func Apply(from, to *Rule, src, dst draw.Image) {
var x, y int
var r, g, b, a uint32
var sc color.Color
var dc color.RGBA
var pix pixel
rect := src.Bounds()
for y = 0; y < rect.Dy(); y++ {
for x = 0; x < rect.Dx(); x++ {
sc = src.At(x, y)
r, g, b, a = sc.RGBA()
pix.r = uint8(r >> 8)
pix.g = uint8(g >> 8)
pix.b = uint8(b >> 8)
pix.a = uint8(a >> 8)
// Check if the pixel matches the filter rule.
if !(match(pix.r, from.R) && match(pix.g, from.G) && match(pix.b, from.B) && match(pix.a, from.A)) {
dst.Set(x, y, sc)
continue
}
// Compute three different types of grayscale conversion.
// These can be applied by named references.
pix.average = uint8(((r + g + b) / 3) >> 8)
pix.lightness = uint8(((min(min(r, g), b) + max(max(r, g), b)) / 2) >> 8)
// For luminosity it is necessary to apply an inverse of the gamma
// function for the color space before calculating the inner product.
// Then you apply the gamma function to the reduced value. Failure to
// incorporate the gamma function can result in errors of up to 20%.
//
// For typical computer stuff, the color space is sRGB. The right
// numbers for sRGB are approx. 0.21, 0.72, 0.07. Gamma for sRGB
// is a composite function that approximates exponentiation by 1/2.2
//
// This is a rather expensive operation, but gives a much more accurate
// and satisfactory result than the average and lightness versions.
pix.luminosity = gammaSRGB(
0.212655*invGammaSRGB(pix.r) +
0.715158*invGammaSRGB(pix.g) +
0.072187*invGammaSRGB(pix.b))
// Transform color.
dc.R = transform(&pix, pix.r, to.R)
dc.G = transform(&pix, pix.g, to.G)
dc.B = transform(&pix, pix.b, to.B)
dc.A = transform(&pix, pix.a, to.A)
// Set new pixel.
dst.Set(x, y, dc)
}
}
}
// MapColorInRectangle is a helper function for working on part of an image. It
// takes the original image, a function to use, a image to write to, and the
// bounds of the original (and therefore the final image) to act upon.
func MapColorInRectangle(img image.Image, bounds image.Rectangle, dest draw.Image,
f Composable) {
for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
for x := bounds.Min.X; x < bounds.Max.X; x++ {
dest.Set(x, y, f(img.At(x, y)))
}
}
}
// decodeP1 reads an ASCII bitmap
func decodeP1(r *bufio.Reader, img draw.Image, width, height uint) {
var x, y int
for y = 0; y < int(height); y++ {
for x = 0; x < int(width); x++ {
img.Set(x, y, color.Alpha{uint8(readU(r)) * 0xff})
}
}
}
func newSetFuncDefault(p draw.Image) SetFunc {
return func(x, y int, r, g, b, a uint32) {
p.Set(x, y, color.RGBA64{
R: uint16(r),
G: uint16(g),
B: uint16(b),
A: uint16(a),
})
}
}
// Blends src image (top layer) into dst image (bottom layer) using
// the BlendFunc provided by mode. BlendFunc is applied to each pixel
// where the src image overlaps the dst image and the result is stored
// in the original dst image, src image is unmutable.
func BlendImage(dst draw.Image, src image.Image, mode BlendFunc) {
// Obtain the intersection of both images.
inter := dst.Bounds().Intersect(src.Bounds())
// Apply BlendFuc to each pixel in the intersection.
for y := inter.Min.Y; y < inter.Max.Y; y++ {
for x := inter.Min.X; x < inter.Max.X; x++ {
dst.Set(x, y, mode(dst.At(x, y), src.At(x, y)))
}
}
}
// DrawLinear draws a linear gradient to dst. If the gradient vector (as
// defined by x0, y0, x1, and y1) is found to be purely horizontal or purely
// vertical, the appropriate optimized functions will be called.
func DrawLinear(dst draw.Image, x0, y0, x1, y1 float64, stops []Stop) {
if y0 == y1 && x0 != x1 {
drawHLinear(dst, x0, x1, stops)
return
}
if x0 == x1 && y0 != y1 {
drawVLinear(dst, y0, y1, stops)
return
}
if len(stops) == 0 {
return
}
if y0 > y1 {
panic(fmt.Sprintf("invalid bounds y0(%f)>y1(%f)", y0, y1))
}
if x0 > x1 {
panic(fmt.Sprintf("invalid bounds x0(%f)>x1(%f)", x0, x1))
}
bb := dst.Bounds()
width, height := bb.Dx(), bb.Dy()
x0, y0 = x0*float64(width), y0*float64(height)
x1, y1 = x1*float64(width), y1*float64(height)
dx, dy := x1-x0, y1-y0
px0, py0 := x0-dy, y0+dx
mag := math.Hypot(dx, dy)
var col color.Color
for y := 0; y < width; y++ {
fy := float64(y)
for x := 0; x < width; x++ {
fx := float64(x)
// is the pixel before the start of the gradient?
s0 := (px0-x0)*(fy-y0) - (py0-y0)*(fx-x0)
if s0 > 0 {
col = stops[0].Col
} else {
// calculate the distance of the pixel from the first stop line
u := ((fx-x0)*(px0-x0) + (fy-y0)*(py0-y0)) /
(mag * mag)
x2, y2 := x0+u*(px0-x0), y0+u*(py0-y0)
d := math.Hypot(fx-x2, fy-y2) / mag
col = getColour(d, stops)
}
dst.Set(x+bb.Min.X, y+bb.Min.Y, col)
}
}
}
func brush(img draw.Image, id int) func(x, y int) {
colors := [][]uint8{
{0, 0, 0xff},
{0xff, 0, 0},
{0xff, 0xff, 0xff},
}
c := colors[id%len(colors)]
return func(x, y int) {
img.Set(x, y, &color.NRGBA{R: c[0], G: c[1], B: c[2], A: 0xff})
}
}
func (burkes) Draw(dst draw.Image, r image.Rectangle, src image.Image, sp image.Point) {
quantError0 := make([][3]int32, r.Dx()+4)
quantError1 := make([][3]int32, r.Dx()+4)
out := color.RGBA64{A: 0xffff}
for y := 0; y != r.Dy(); y++ {
for x := 0; x != r.Dx(); x++ {
sr, sg, sb, _ := src.At(sp.X+x, sp.Y+y).RGBA()
er, eg, eb := int32(sr), int32(sg), int32(sb)
er = clamp(er + quantError0[x+2][0]/32)
eg = clamp(eg + quantError0[x+2][1]/32)
eb = clamp(eb + quantError0[x+2][2]/32)
out.R = uint16(er)
out.G = uint16(eg)
out.B = uint16(eb)
dst.Set(r.Min.X+x, r.Min.Y+y, &out)
sr, sg, sb, _ = dst.At(r.Min.X+x, r.Min.Y+y).RGBA()
er -= int32(sr)
eg -= int32(sg)
eb -= int32(sb)
quantError0[x+3][0] += er * 8
quantError0[x+3][1] += eg * 8
quantError0[x+3][2] += eb * 8
quantError0[x+4][0] += er * 4
quantError0[x+4][1] += eg * 4
quantError0[x+4][2] += eb * 4
quantError1[x+0][0] += er * 2
quantError1[x+0][1] += eg * 2
quantError1[x+0][2] += eb * 2
quantError1[x+1][0] += er * 4
quantError1[x+1][1] += eg * 4
quantError1[x+1][2] += eb * 4
quantError1[x+2][0] += er * 8
quantError1[x+2][1] += eg * 8
quantError1[x+2][2] += eb * 8
quantError1[x+3][0] += er * 4
quantError1[x+3][1] += eg * 4
quantError1[x+3][2] += eb * 4
quantError1[x+4][0] += er * 2
quantError1[x+4][1] += eg * 2
quantError1[x+4][2] += eb * 2
}
// Recycle the quantization error buffers.
quantError0, quantError1 = quantError1, quantError0
for i := range quantError1 {
quantError1[i] = [3]int32{}
}
}
}
func (hs *AutoSlicer) drawRegion(img draw.Image, r Region) {
var (
c color.Color
x, y int
)
c = color.RGBA{0xFF, 0, 0, 0xFF}
for x = r.Min.X + 1; x < r.Max.X; x++ {
for y = r.Min.Y + 1; y < r.Max.Y; y++ {
img.Set(x, y, c)
}
}
}
// decodeP2 reads an ASCII graymap
func decodeP2(r *bufio.Reader, img draw.Image, width, height uint) {
var x, y int
mask := readU(r)
mul := 255 / mask
for y = 0; y < int(height); y++ {
for x = 0; x < int(width); x++ {
img.Set(x, y, color.Gray{uint8((readU(r) & mask) * mul)})
}
}
}
func noise(src draw.Image) {
orig := src.Bounds()
numToMod := (orig.Max.X * orig.Max.Y) / 2
for i := 0; i < numToMod; i++ {
x := rand.Intn(orig.Max.X)
y := rand.Intn(orig.Max.Y)
origColor := src.At(x, y).(color.RGBA)
origColor.R += 30
origColor.B += 30
origColor.G += 30
src.Set(x, y, origColor)
}
}
func DrawDigit(dest draw.Image, dig digitmap, sx int, sy int) {
c := 0
for y, h := sy, 0; h < 7; y, h = y+1, h+1 {
for x, w := sx, 0; w < 4; x, w = x+1, w+1 {
if dig[c] > 0 {
dest.Set(x, y, color.White)
} else {
dest.Set(x, y, color.Black)
}
c += 1
}
}
}
// 旋转，每单位1代表左旋90度。注意采用的是向右向上的直角坐标系，和图像的向右向下不同。
// 本包的函数都是采用向右向上的直角坐标系。因此在图像显示上，每单位1右旋90度。
func Rotate(dst draw.Image, src image.Image, act int) error {
var to func(int, int) (int, int)
sr := src.Bounds()
dr := dst.Bounds()
W := dr.Max.X - dr.Min.X
H := dr.Max.Y - dr.Min.Y
if H <= 0 || W <= 0 {
return errors.New("target image is empty or noncanonical")
}
if sr.Min.X >= sr.Max.X || sr.Min.Y >= sr.Max.Y {
return errors.New("source image is empty or noncanonical")
}
switch act %= 4; act {
case 2, -2:
if sr.Max.X-sr.Min.X != W || sr.Max.Y-sr.Min.Y != H {
return errors.New("target and source must be same size!")
}
to = func(x, y int) (int, int) {
return W - 1 - x, H - 1 - y
}
case 1, -3:
if sr.Max.X-sr.Min.X != H || sr.Max.Y-sr.Min.Y != W {
return errors.New("target and source must be same size!")
}
to = func(x, y int) (int, int) {
return H - 1 - y, x
}
case -1, 3:
if sr.Max.X-sr.Min.X != H || sr.Max.Y-sr.Min.Y != W {
return errors.New("target and source must be same size!")
}
to = func(x, y int) (int, int) {
return y, W - 1 - x
}
case 0:
if sr.Max.X-sr.Min.X != W || sr.Max.Y-sr.Min.Y != H {
return errors.New("target and source must be same size!")
}
to = func(x, y int) (int, int) {
return x, y
}
}
for i := 0; i < W; i++ {
for j := 0; j < H; j++ {
x, y := to(i, j)
dst.Set(dr.Min.X+x, dr.Min.Y+y, src.At(sr.Min.X+i, sr.Min.Y+j))
}
}
return nil
}
func digit(im draw.Image, col color.Color, x, y, size, digit int) {
n := hexdigits[digit]
for _, s := range segments {
if n&1 != 0 {
xx, yy := x+s.sx*size, y+s.sy*size
for i := 0; i <= size; i++ {
im.Set(xx, yy, col)
xx += s.dx
yy += s.dy
}
}
n >>= 1
}
}
/* Line drawing - Bresenhams algorithm in it's simplest form.*/
func DrawLine(screen draw.Image, a image.Point, b image.Point, color color.Color) {
dx := b.X - a.X
dy := b.Y - a.Y
error := 0.0
derr := math.Abs(float64(dy) / float64(dx))
y := a.Y
for x := a.X; x < b.X; x++ {
screen.Set(x, y, color)
error += derr
if error >= 0.5 {
y++
error -= 1.0
}
}
}
func DrawColon(dest draw.Image, sx int, sy int) {
c := 0
for y, h := sy, 0; h < 7; y, h = y+1, h+1 {
for x, w := sx, 0; w < 2; x, w = x+1, w+1 {
if colonslice[c] > 0 {
dest.Set(x, y, color.White)
} else {
dest.Set(x, y, color.Black)
}
c += 1
}
}
}
func FillArc(horizontal, vertical int, imagem draw.Image, cor color.Color) {
var passo int
if vertical > 0 {
passo = 1
} else {
passo = -1
}
for indice := 0; indice != vertical; indice += passo {
imagem.Set(horizontal, indice, cor)
imagem.Set(indice, horizontal, cor)
}
imagem.Set(horizontal, vertical, cor)
imagem.Set(vertical, horizontal, cor)
}
func DrawImage(src image.Image, dest draw.Image, tr MatrixTransform, op draw.Op, filter ImageFilter) {
bounds := src.Bounds()
x0, y0, x1, y1 := float64(bounds.Min.X), float64(bounds.Min.Y), float64(bounds.Max.X), float64(bounds.Max.Y)
tr.TransformRectangle(&x0, &y0, &x1, &y1)
var x, y, u, v float64
var c1, c2, cr color.Color
var r, g, b, a, ia, r1, g1, b1, a1, r2, g2, b2, a2 uint32
var color color.RGBA
for x = x0; x < x1; x++ {
for y = y0; y < y1; y++ {
u = x
v = y
tr.InverseTransform(&u, &v)
if bounds.Min.X <= int(u) && bounds.Max.X > int(u) && bounds.Min.Y <= int(v) && bounds.Max.Y > int(v) {
c1 = dest.At(int(x), int(y))
switch filter {
case LinearFilter:
c2 = src.At(int(u), int(v))
case BilinearFilter:
c2 = getColorBilinear(src, u, v)
case BicubicFilter:
c2 = getColorBicubic(src, u, v)
}
switch op {
case draw.Over:
r1, g1, b1, a1 = c1.RGBA()
r2, g2, b2, a2 = c2.RGBA()
ia = M - a2
r = ((r1 * ia) / M) + r2
g = ((g1 * ia) / M) + g2
b = ((b1 * ia) / M) + b2
a = ((a1 * ia) / M) + a2
color.R = uint8(r >> 8)
color.G = uint8(g >> 8)
color.B = uint8(b >> 8)
color.A = uint8(a >> 8)
cr = color
default:
cr = c2
}
dest.Set(int(x), int(y), cr)
}
}
}
}