dithering
This commit is contained in:
zuckerberg
parent
bfbd0a63cc
commit
95729c7228
234
server/main.go
234
server/main.go
@ -12,7 +12,6 @@ import (
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"image/color"
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"image/draw"
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_ "image/gif"
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"image/jpeg"
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_ "image/jpeg"
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_ "image/png"
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@ -52,49 +51,18 @@ const (
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)
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type ColorDefinition struct {
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Color color.RGBA
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Color Colorf
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Code EInkColor
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}
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// var Colors = []ColorDefinition{
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// {color.RGBA{0, 0, 0, 255}, EPD_7IN3F_BLACK},
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// {color.RGBA{255, 255, 255, 255}, EPD_7IN3F_WHITE},
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// {color.RGBA{0, 255, 0, 255}, EPD_7IN3F_GREEN},
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// {color.RGBA{0, 0, 255, 255}, EPD_7IN3F_BLUE},
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// {color.RGBA{255, 0, 0, 255}, EPD_7IN3F_RED},
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// {color.RGBA{255, 255, 0, 255}, EPD_7IN3F_YELLOW},
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// {color.RGBA{255, 165, 0, 255}, EPD_7IN3F_ORANGE},
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// }
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var Colors = []ColorDefinition{
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{color.RGBA{0, 0, 0, 255}, EPD_7IN3F_BLACK},
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{color.RGBA{255, 255, 255, 255}, EPD_7IN3F_WHITE},
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{color.RGBA{16, 84, 31, 255}, EPD_7IN3F_GREEN},
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{color.RGBA{16, 38, 86, 255}, EPD_7IN3F_BLUE},
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{color.RGBA{147, 17, 3, 255}, EPD_7IN3F_RED},
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{color.RGBA{251, 193, 2, 255}, EPD_7IN3F_YELLOW},
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{color.RGBA{203, 66, 5, 255}, EPD_7IN3F_ORANGE},
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}
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func ConvertToEInkColor(c color.RGBA) EInkColor {
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minDist := math.MaxFloat64
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minCode := EInkColor(0)
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for _, def := range Colors {
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dist := colorDistance(c, def.Color)
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if dist < minDist {
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minDist = dist
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minCode = def.Code
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}
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}
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return minCode
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}
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func colorDistance(a, b color.RGBA) float64 {
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// r := float64(a.R) - float64(b.R)
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// g := float64(a.G) - float64(b.G)
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// bb := float64(a.B) - float64(b.B)
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// return math.Sqrt(r*r + g*g + bb*bb)
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return ciede2000.Diff(a, b)
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{Colorf{0, 0, 0}, EPD_7IN3F_BLACK},
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{Colorf{1, 1, 1}, EPD_7IN3F_WHITE},
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{Colorf{0.059, 0.329, 0.119}, EPD_7IN3F_GREEN},
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{Colorf{0.061, 0.147, 0.336}, EPD_7IN3F_BLUE},
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{Colorf{0.574, 0.066, 0.010}, EPD_7IN3F_RED},
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{Colorf{0.982, 0.756, 0.004}, EPD_7IN3F_YELLOW},
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{Colorf{0.795, 0.255, 0.018}, EPD_7IN3F_ORANGE},
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}
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func imageToRGBA(src image.Image) *image.RGBA {
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@ -110,20 +78,144 @@ func imageToRGBA(src image.Image) *image.RGBA {
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return dst
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}
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func ConvertToEInkImage(src image.Image) []byte {
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rgbImage := imageToRGBA(src)
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// Colorf represents a color with float64 RGB values.
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type Colorf struct {
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R, G, B float64
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}
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var image []byte
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// Convert an image to a 2D array of Colorf.
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func convertImageToColors(src image.Image) [][]Colorf {
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img := imageToRGBA(src)
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for y := 0; y < src.Bounds().Max.Y; y++ {
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for x := 0; x < src.Bounds().Max.X; x++ {
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image = append(image, byte(ConvertToEInkColor(rgbImage.RGBAAt(x, y))))
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bounds := img.Bounds()
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width, height := bounds.Max.X, bounds.Max.Y
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// Initialize the 2D slice.
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colorfImg := make([][]Colorf, height)
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for i := range colorfImg {
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colorfImg[i] = make([]Colorf, width)
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}
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// Iterate over each pixel.
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for y := 0; y < height; y++ {
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for x := 0; x < width; x++ {
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r, g, b, _ := img.At(x, y).RGBA()
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// Convert the uint32 color values to float64, normalized to [0, 1].
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colorf := Colorf{
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R: float64(r) / 0xffff,
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G: float64(g) / 0xffff,
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B: float64(b) / 0xffff,
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}
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colorfImg[y][x] = colorf
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}
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}
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image = packBytesIntoNibbles(image)
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return colorfImg
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}
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return image
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func convertToRGBA(colorf Colorf) color.RGBA {
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// Convert the float64 color values to uint8, and ignore the alpha channel.
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return color.RGBA{
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R: uint8(colorf.R * 255),
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G: uint8(colorf.G * 255),
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B: uint8(colorf.B * 255),
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A: 255,
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}
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}
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func subtractColorf(c1, c2 Colorf) Colorf {
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return Colorf{
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R: c1.R - c2.R,
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G: c1.G - c2.G,
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B: c1.B - c2.B,
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}
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}
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func addColorf(c1, c2 Colorf) Colorf {
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return Colorf{
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R: c1.R + c2.R,
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G: c1.G + c2.G,
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B: c1.B + c2.B,
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}
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}
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func multColor(c Colorf, m float64) Colorf {
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return Colorf{
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R: c.R * m,
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G: c.G * m,
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B: c.B * m,
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}
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}
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func clampColor(value Colorf, min, max float64) Colorf {
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return Colorf{
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R: clamp(value.R, min, max),
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G: clamp(value.G, min, max),
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B: clamp(value.B, min, max),
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}
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}
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func clamp(value, min, max float64) float64 {
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if value < min {
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return min
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}
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if value > max {
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return max
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}
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return value
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}
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func ditherFloydSteinberg(image [][]Colorf, x int, y int, diff Colorf) {
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height := len(image)
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width := len(image[0])
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if x < 0 || y < 0 || x >= width || y >= height {
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return
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}
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image[y][x] = clampColor(addColorf(image[y][x], diff), 0, 1)
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}
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func ConvertToEInkImage(src image.Image) []byte {
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bounds := src.Bounds()
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width, height := bounds.Max.X, bounds.Max.Y
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image := convertImageToColors(src)
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var einkImage []byte
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for y := 0; y < height; y++ {
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for x := 0; x < width; x++ {
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// find closest color
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minDist := math.MaxFloat64
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bestColorCode := EInkColor(0)
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bestColor := Colorf{0, 0, 0}
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for _, def := range Colors {
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dist := ciede2000.Diff(convertToRGBA(image[y][x]), convertToRGBA(def.Color))
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if dist < minDist {
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minDist = dist
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bestColorCode = def.Code
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bestColor = def.Color
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}
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}
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einkImage = append(einkImage, byte(bestColorCode))
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// dither colors using Floyd-Steinberg to create the illusion of shading
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diff := subtractColorf(image[y][x], bestColor)
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ditherFloydSteinberg(image, x+1, y, multColor(diff, 7.0/16.0))
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ditherFloydSteinberg(image, x-1, y+1, multColor(diff, 3.0/16.0))
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ditherFloydSteinberg(image, x, y+1, multColor(diff, 5.0/16.0))
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ditherFloydSteinberg(image, x+1, y+1, multColor(diff, 1.0/16.0))
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}
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}
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einkImage = packBytesIntoNibbles(einkImage)
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return einkImage
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}
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func packBytesIntoNibbles(input []byte) []byte {
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@ -163,51 +255,7 @@ func getImage(w http.ResponseWriter, r *http.Request) {
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resizedImg := resize.Resize(800, 480, croppedImg, resize.Lanczos3)
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// Now you can save the cropped image
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outFile, err := os.Create("cropped_image.jpg")
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if err != nil {
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fmt.Println("Error: File could not be created")
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os.Exit(1)
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}
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defer outFile.Close()
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err = jpeg.Encode(outFile, resizedImg, nil)
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if err != nil {
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fmt.Println("Error: Image could not be encoded")
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os.Exit(1)
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}
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fmt.Println("Cropped image saved successfully")
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// data := ConvertToEInkImage(resizedImg)
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colors := []EInkColor{
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EPD_7IN3F_BLACK, EPD_7IN3F_BLUE, EPD_7IN3F_GREEN, EPD_7IN3F_ORANGE,
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EPD_7IN3F_RED, EPD_7IN3F_YELLOW, EPD_7IN3F_WHITE, EPD_7IN3F_WHITE,
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}
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var data []byte
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for i := 0; i < 240; i++ {
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for k := 0; k < 4; k++ {
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for j := 0; j < 100; j++ {
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data = append(data, (byte(colors[k]<<4))|byte(colors[k]))
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}
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}
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}
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for i := 0; i < 240; i++ {
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for k := 4; k < 8; k++ {
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for j := 0; j < 100; j++ {
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data = append(data, (byte(colors[k]<<4))|byte(colors[k]))
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}
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}
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}
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// // Fill the array with byte K
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// for i := 0; i < 800*480/2; i++ {
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// data = append(data, (colors[0]<<4)|colors[6])
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// }
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data := ConvertToEInkImage(resizedImg)
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w.Header().Set("Content-Length", strconv.Itoa(len(data)))
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fmt.Printf("Bytes to send: %+v\n", len(data))
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