// Halves the width of the double-width image created by hxl to produce nice
// smooth edges.
func halveWidth(img image.Image) image.Image {
b := img.Bounds()
o := image.NewRGBA(image.Rect(0, 0, b.Dx()/2, b.Dy()))
for y := 0; y < b.Dy(); y++ {
for x := 0; x < b.Dx()/2; x++ {
l := img.At(x*2, y)
r := img.At(x*2+1, y)
o.Set(x, y, utils.Average(l, r))
}
}
return o
}
func paintAverage(img image.Image, bounds image.Rectangle, dest draw.Image,
c chan int) {
values := make([]color.Color, bounds.Dx()*bounds.Dy())
count := 0
utils.EachColorInRectangle(img, bounds, func(c color.Color) {
values[count] = c
count++
})
avg := utils.Average(values...)
utils.MapColorInRectangle(img, bounds, dest, func(c color.Color) color.Color {
return avg
})
c <- 1
}
// Hxl pixelates the Image into equilateral triangles with the width
// given. These are arranged into hexagonal shapes.
func Hxl(img image.Image, width int) image.Image {
b := img.Bounds()
pixelHeight := width * 2
pixelWidth := width
cols := b.Dx() / pixelWidth
rows := b.Dy() / pixelHeight
o := image.NewRGBA(image.Rect(0, 0, pixelWidth*cols*2, pixelHeight*rows))
// Note: "Top" doesn't mean above the x-axis, it means in the triangle
// pointing towards the x-axis.
inTop := func(x, y float64) bool {
return (x >= 0 && y >= x) || (x <= 0 && y >= -x)
}
// Same for "Bottom" this is the triangle below and pointing towards the
// x-axis.
inBottom := func(x, y float64) bool {
return (x >= 0 && y <= -x) || (x <= 0 && y <= x)
}
for col := 0; col < cols; col++ {
for row := 0; row < rows; row++ {
north := []color.Color{}
south := []color.Color{}
for y := 0; y < pixelHeight; y++ {
for x := 0; x < pixelWidth; x++ {
realY := row*pixelHeight + y
realX := col*pixelWidth + x
pixel := img.At(realX, realY)
yOrigin := float64(y - pixelHeight/2)
xOrigin := float64(x - pixelWidth/2)
if inTop(xOrigin, yOrigin) {
north = append(north, pixel)
} else if inBottom(xOrigin, yOrigin) {
south = append(south, pixel)
}
}
}
top := utils.Average(north...)
bot := utils.Average(south...)
for y := 0; y < pixelHeight; y++ {
for x := 0; x < pixelWidth*2; x++ {
realY := row*pixelHeight + y
realX := col*pixelWidth*2 + x
yOrigin := float64(y - pixelHeight/2)
xOrigin := float64(x - pixelWidth*2/2)
if inTop(xOrigin, yOrigin) {
o.Set(realX, realY, top)
} else if inBottom(xOrigin, yOrigin) {
o.Set(realX, realY, bot)
}
}
}
}
}
// Now for the shifted version
offsetY := pixelHeight / 2
offsetX := pixelWidth / 2
for col := -1; col < cols; col++ {
for row := -1; row < rows; row++ {
north := []color.Color{}
south := []color.Color{}
for y := 0; y < pixelHeight; y++ {
for x := 0; x < pixelWidth; x++ {
realY := row*pixelHeight + y + offsetY
realX := col*pixelWidth + x + offsetX
if realX >= 0 && realX < b.Dx() {
pixel := img.At(realX, realY)
yOrigin := float64(y - pixelHeight/2)
xOrigin := float64(x - pixelWidth/2)
if inTop(xOrigin, yOrigin) {
north = append(north, pixel)
} else if inBottom(xOrigin, yOrigin) {
south = append(south, pixel)
}
}
}
}
top := utils.Average(north...)
bot := utils.Average(south...)
for y := 0; y < pixelHeight; y++ {
for x := 0; x < pixelWidth*2; x++ {
realY := row*pixelHeight + y + offsetY
realX := col*pixelWidth*2 + x + offsetX*2
yOrigin := float64(y - pixelHeight/2)
xOrigin := float64(x - pixelWidth*2/2)
if inTop(xOrigin, yOrigin) {
o.Set(realX, realY, top)
} else if inBottom(xOrigin, yOrigin) {
o.Set(realX, realY, bot)
}
}
}
}
}
return halveWidth(o)
}
func pxlWorker(img image.Image, bounds image.Rectangle, dest draw.Image,
size utils.Dimension, triangle Triangle, aliased bool, c chan int) {
ratio := float64(size.H) / float64(size.W)
inTop := func(x, y float64) bool {
return (y > ratio*x) && (y > ratio*-x)
}
inRight := func(x, y float64) bool {
return (y < ratio*x) && (y > ratio*-x)
}
inBottom := func(x, y float64) bool {
return (y < ratio*x) && (y < ratio*-x)
}
inLeft := func(x, y float64) bool {
return (y > ratio*x) && (y < ratio*-x)
}
to := []color.Color{}
ri := []color.Color{}
bo := []color.Color{}
le := []color.Color{}
for y := 0; y < bounds.Dy(); y++ {
for x := 0; x < bounds.Dx(); x++ {
realY := bounds.Min.Y + y
realX := bounds.Min.X + x
yOrigin := float64(y - size.H/2)
xOrigin := float64(x - size.W/2)
if inTop(xOrigin, yOrigin) {
to = append(to, img.At(realX, realY))
} else if inRight(xOrigin, yOrigin) {
ri = append(ri, img.At(realX, realY))
} else if inBottom(xOrigin, yOrigin) {
bo = append(bo, img.At(realX, realY))
} else if inLeft(xOrigin, yOrigin) {
le = append(le, img.At(realX, realY))
}
}
}
ato := utils.Average(to...)
ari := utils.Average(ri...)
abo := utils.Average(bo...)
ale := utils.Average(le...)
if (triangle != LEFT) && (triangle == RIGHT ||
utils.Closeness(ato, ari) > utils.Closeness(ato, ale)) {
topRight := utils.Average(ato, ari)
bottomLeft := utils.Average(abo, ale)
middle := utils.Average(topRight, bottomLeft)
for y := 0; y < bounds.Dy(); y++ {
for x := 0; x < bounds.Dx(); x++ {
realY := bounds.Min.Y + y
realX := bounds.Min.X + x
yOrigin := float64(y - size.H/2)
xOrigin := float64(x - size.W/2)
if yOrigin > ratio*xOrigin {
dest.Set(realX, realY, topRight)
} else if yOrigin == ratio*xOrigin && !aliased {
dest.Set(realX, realY, middle)
} else {
dest.Set(realX, realY, bottomLeft)
}
}
}
} else {
topLeft := utils.Average(ato, ale)
bottomRight := utils.Average(abo, ari)
middle := utils.Average(topLeft, bottomRight)
for y := 0; y < bounds.Dy(); y++ {
for x := 0; x < bounds.Dx(); x++ {
realY := bounds.Min.Y + y
realX := bounds.Min.X + x
yOrigin := float64(y - size.H/2)
xOrigin := float64(x - size.W/2)
// Do this one opposite to above so that the diagonals line up when
// aliased.
if yOrigin < ratio*-xOrigin {
dest.Set(realX, realY, bottomRight)
} else if yOrigin == ratio*-xOrigin && !aliased {
dest.Set(realX, realY, middle)
} else {
dest.Set(realX, realY, topLeft)
}
}
}
}
c <- 1
}
// Vxl pixelates the Image into isometric cubes. It averages the colours and
// naïvely darkens and lightens the colours to mimic highlight and shade.
func Vxl(img image.Image, height int, flip bool, top, left, right float64) image.Image {
b := img.Bounds()
pixelHeight := height
pixelWidth := int(math.Sqrt(3.0) * float64(pixelHeight) / 2.0)
cols := b.Dx() / pixelWidth
rows := b.Dy() / pixelHeight
// intersection of lines
c := float64(pixelHeight) / 2
// gradient of lines
k := math.Sqrt(3.0) / 3.0
o := image.NewRGBA(image.Rect(0, 0, pixelWidth*cols, pixelHeight*rows))
// See: http://www.flickr.com/photos/hawx-/8466236036/
inTopSquare := func(x, y float64) bool {
if !flip {
y *= -1
}
return y <= -k*x+c && y >= k*x && y >= -k*x && y <= k*x+c
}
inBottomRight := func(x, y float64) bool {
if !flip {
y *= -1
}
return x >= 0 && y <= k*x && y >= k*x-c
}
inBottomLeft := func(x, y float64) bool {
if !flip {
y *= -1
}
return x <= 0 && y <= -k*x && y >= -k*x-c
}
inHexagon := func(x, y float64) bool {
return inTopSquare(x, y) || inBottomRight(x, y) || inBottomLeft(x, y)
}
topL := channel.AdjustC(utils.Multiplier(top), channel.Lightness)
rightL := channel.AdjustC(utils.Multiplier(right), channel.Lightness)
leftL := channel.AdjustC(utils.Multiplier(left), channel.Lightness)
for col := 0; col < cols; col++ {
for row := 0; row < rows; row++ {
seen := []color.Color{}
for y := 0; y < pixelHeight; y++ {
for x := 0; x < pixelWidth; x++ {
realY := row*(pixelHeight+int(c)) + y
realX := col*pixelWidth + x
pixel := img.At(realX, realY)
yOrigin := float64(y - pixelHeight/2)
xOrigin := float64(x - pixelWidth/2)
if inHexagon(xOrigin, yOrigin) {
seen = append(seen, pixel)
}
}
}
average := utils.Average(seen...)
for y := 0; y < pixelHeight; y++ {
for x := 0; x < pixelWidth; x++ {
realY := row*(pixelHeight+int(c)) + y
realX := col*pixelWidth + x
yOrigin := float64(y - pixelHeight/2)
xOrigin := float64(x - pixelWidth/2)
// This stops white bits showing above the top squares. It does mean
// the dimensions aren't perfect, but what did you expect with pixels
// and trig. It is inefficient though, maybe fix that later?
if (!flip && yOrigin < 0) || (flip && yOrigin > 0) {
o.Set(realX, realY, topL(average))
} else {
if xOrigin > 0 {
o.Set(realX, realY, rightL(average))
} else {
o.Set(realX, realY, leftL(average))
}
}
if inTopSquare(xOrigin, yOrigin) {
o.Set(realX, realY, topL(average))
}
if inBottomRight(xOrigin, yOrigin) {
o.Set(realX, realY, rightL(average))
}
if inBottomLeft(xOrigin, yOrigin) {
o.Set(realX, realY, leftL(average))
}
}
}
}
}
offsetY := (pixelHeight + int(c)) / 2.0
offsetX := pixelWidth / 2
for col := -1; col < cols; col++ {
for row := -1; row < rows; row++ {
seen := []color.Color{}
for y := 0; y < pixelHeight; y++ {
for x := 0; x < pixelWidth; x++ {
realY := row*(pixelHeight+int(c)) + y + offsetY
realX := col*pixelWidth + x + offsetX
if image.Pt(realX, realY).In(b) {
pixel := img.At(realX, realY)
yOrigin := float64(y - pixelHeight/2)
xOrigin := float64(x - pixelWidth/2)
if inHexagon(xOrigin, yOrigin) {
seen = append(seen, pixel)
}
}
}
}
if len(seen) <= 0 {
continue
}
average := utils.Average(seen...)
for y := 0; y < pixelHeight; y++ {
for x := 0; x < pixelWidth; x++ {
realY := row*(pixelHeight+int(c)) + y + offsetY
realX := col*pixelWidth + x + offsetX
yOrigin := float64(y - pixelHeight/2)
xOrigin := float64(x - pixelWidth/2)
if inTopSquare(xOrigin, yOrigin) {
o.Set(realX, realY, topL(average))
}
if inBottomRight(xOrigin, yOrigin) {
o.Set(realX, realY, rightL(average))
}
if inBottomLeft(xOrigin, yOrigin) {
o.Set(realX, realY, leftL(average))
}
}
}
}
}
return o
}
