func runChannel(cmd *Command, args []string) {
i := utils.ReadStdin()
var adj utils.Adjuster
if utils.FlagVisited("by", cmd.Flag) {
adj = utils.Adder(channelBy)
} else {
adj = utils.Multiplier(channelRatio)
}
if !(channelRed || channelGreen || channelBlue || channelHue ||
channelSaturation || channelLightness || channelBrightness || channelAlpha) {
channelRed = true
channelGreen = true
channelBlue = true
}
if channelRed {
i = channel.Red(i, adj)
}
if channelGreen {
i = channel.Green(i, adj)
}
if channelBlue {
i = channel.Blue(i, adj)
}
if channelHue {
i = channel.Hue(i, adj)
}
if channelSaturation {
i = channel.Saturation(i, adj)
}
if channelLightness {
i = channel.Lightness(i, adj)
}
if channelBrightness {
i = channel.Brightness(i, adj)
}
if channelAlpha {
i = channel.Alpha(i, adj)
}
utils.WriteStdout(i)
}
// 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.LightnessC(utils.Multiplier(top))
rightL := channel.LightnessC(utils.Multiplier(right))
leftL := channel.LightnessC(utils.Multiplier(left))
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)
y_origin := float64(y - pixelHeight/2)
x_origin := float64(x - pixelWidth/2)
if inHexagon(x_origin, y_origin) {
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
y_origin := float64(y - pixelHeight/2)
x_origin := 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 && y_origin < 0) || (flip && y_origin > 0) {
o.Set(realX, realY, topL(average))
} else {
if x_origin > 0 {
o.Set(realX, realY, rightL(average))
} else {
o.Set(realX, realY, leftL(average))
}
}
if inTopSquare(x_origin, y_origin) {
o.Set(realX, realY, topL(average))
}
if inBottomRight(x_origin, y_origin) {
o.Set(realX, realY, rightL(average))
}
if inBottomLeft(x_origin, y_origin) {
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)
y_origin := float64(y - pixelHeight/2)
x_origin := float64(x - pixelWidth/2)
if inHexagon(x_origin, y_origin) {
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
y_origin := float64(y - pixelHeight/2)
x_origin := float64(x - pixelWidth/2)
if inTopSquare(x_origin, y_origin) {
o.Set(realX, realY, topL(average))
}
if inBottomRight(x_origin, y_origin) {
o.Set(realX, realY, rightL(average))
}
if inBottomLeft(x_origin, y_origin) {
o.Set(realX, realY, leftL(average))
}
}
}
}
}
return o
}