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authorWim <wim@42.be>2020-12-31 14:48:12 +0100
committerGitHub <noreply@github.com>2020-12-31 14:48:12 +0100
commit4f20ebead36876a88391bf033d1de3e4cf0228da (patch)
tree70b6fd79c6a5e00c958c29a7bd3926f074e76ba6 /vendor/github.com/disintegration/imaging/adjust.go
parenta9f89dbc645aafc68daa9fc8d589f55104b535c7 (diff)
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Update vendor for next release (#1343)
Diffstat (limited to 'vendor/github.com/disintegration/imaging/adjust.go')
-rw-r--r--vendor/github.com/disintegration/imaging/adjust.go253
1 files changed, 253 insertions, 0 deletions
diff --git a/vendor/github.com/disintegration/imaging/adjust.go b/vendor/github.com/disintegration/imaging/adjust.go
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--- /dev/null
+++ b/vendor/github.com/disintegration/imaging/adjust.go
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+package imaging
+
+import (
+ "image"
+ "image/color"
+ "math"
+)
+
+// Grayscale produces a grayscale version of the image.
+func Grayscale(img image.Image) *image.NRGBA {
+ src := newScanner(img)
+ dst := image.NewNRGBA(image.Rect(0, 0, src.w, src.h))
+ parallel(0, src.h, func(ys <-chan int) {
+ for y := range ys {
+ i := y * dst.Stride
+ src.scan(0, y, src.w, y+1, dst.Pix[i:i+src.w*4])
+ for x := 0; x < src.w; x++ {
+ d := dst.Pix[i : i+3 : i+3]
+ r := d[0]
+ g := d[1]
+ b := d[2]
+ f := 0.299*float64(r) + 0.587*float64(g) + 0.114*float64(b)
+ y := uint8(f + 0.5)
+ d[0] = y
+ d[1] = y
+ d[2] = y
+ i += 4
+ }
+ }
+ })
+ return dst
+}
+
+// Invert produces an inverted (negated) version of the image.
+func Invert(img image.Image) *image.NRGBA {
+ src := newScanner(img)
+ dst := image.NewNRGBA(image.Rect(0, 0, src.w, src.h))
+ parallel(0, src.h, func(ys <-chan int) {
+ for y := range ys {
+ i := y * dst.Stride
+ src.scan(0, y, src.w, y+1, dst.Pix[i:i+src.w*4])
+ for x := 0; x < src.w; x++ {
+ d := dst.Pix[i : i+3 : i+3]
+ d[0] = 255 - d[0]
+ d[1] = 255 - d[1]
+ d[2] = 255 - d[2]
+ i += 4
+ }
+ }
+ })
+ return dst
+}
+
+// AdjustSaturation changes the saturation of the image using the percentage parameter and returns the adjusted image.
+// The percentage must be in the range (-100, 100).
+// The percentage = 0 gives the original image.
+// The percentage = 100 gives the image with the saturation value doubled for each pixel.
+// The percentage = -100 gives the image with the saturation value zeroed for each pixel (grayscale).
+//
+// Examples:
+// dstImage = imaging.AdjustSaturation(srcImage, 25) // Increase image saturation by 25%.
+// dstImage = imaging.AdjustSaturation(srcImage, -10) // Decrease image saturation by 10%.
+//
+func AdjustSaturation(img image.Image, percentage float64) *image.NRGBA {
+ percentage = math.Min(math.Max(percentage, -100), 100)
+ multiplier := 1 + percentage/100
+
+ return AdjustFunc(img, func(c color.NRGBA) color.NRGBA {
+ h, s, l := rgbToHSL(c.R, c.G, c.B)
+ s *= multiplier
+ if s > 1 {
+ s = 1
+ }
+ r, g, b := hslToRGB(h, s, l)
+ return color.NRGBA{r, g, b, c.A}
+ })
+}
+
+// AdjustContrast changes the contrast of the image using the percentage parameter and returns the adjusted image.
+// The percentage must be in range (-100, 100). The percentage = 0 gives the original image.
+// The percentage = -100 gives solid gray image.
+//
+// Examples:
+//
+// dstImage = imaging.AdjustContrast(srcImage, -10) // Decrease image contrast by 10%.
+// dstImage = imaging.AdjustContrast(srcImage, 20) // Increase image contrast by 20%.
+//
+func AdjustContrast(img image.Image, percentage float64) *image.NRGBA {
+ percentage = math.Min(math.Max(percentage, -100.0), 100.0)
+ lut := make([]uint8, 256)
+
+ v := (100.0 + percentage) / 100.0
+ for i := 0; i < 256; i++ {
+ switch {
+ case 0 <= v && v <= 1:
+ lut[i] = clamp((0.5 + (float64(i)/255.0-0.5)*v) * 255.0)
+ case 1 < v && v < 2:
+ lut[i] = clamp((0.5 + (float64(i)/255.0-0.5)*(1/(2.0-v))) * 255.0)
+ default:
+ lut[i] = uint8(float64(i)/255.0+0.5) * 255
+ }
+ }
+
+ return adjustLUT(img, lut)
+}
+
+// AdjustBrightness changes the brightness of the image using the percentage parameter and returns the adjusted image.
+// The percentage must be in range (-100, 100). The percentage = 0 gives the original image.
+// The percentage = -100 gives solid black image. The percentage = 100 gives solid white image.
+//
+// Examples:
+//
+// dstImage = imaging.AdjustBrightness(srcImage, -15) // Decrease image brightness by 15%.
+// dstImage = imaging.AdjustBrightness(srcImage, 10) // Increase image brightness by 10%.
+//
+func AdjustBrightness(img image.Image, percentage float64) *image.NRGBA {
+ percentage = math.Min(math.Max(percentage, -100.0), 100.0)
+ lut := make([]uint8, 256)
+
+ shift := 255.0 * percentage / 100.0
+ for i := 0; i < 256; i++ {
+ lut[i] = clamp(float64(i) + shift)
+ }
+
+ return adjustLUT(img, lut)
+}
+
+// AdjustGamma performs a gamma correction on the image and returns the adjusted image.
+// Gamma parameter must be positive. Gamma = 1.0 gives the original image.
+// Gamma less than 1.0 darkens the image and gamma greater than 1.0 lightens it.
+//
+// Example:
+//
+// dstImage = imaging.AdjustGamma(srcImage, 0.7)
+//
+func AdjustGamma(img image.Image, gamma float64) *image.NRGBA {
+ e := 1.0 / math.Max(gamma, 0.0001)
+ lut := make([]uint8, 256)
+
+ for i := 0; i < 256; i++ {
+ lut[i] = clamp(math.Pow(float64(i)/255.0, e) * 255.0)
+ }
+
+ return adjustLUT(img, lut)
+}
+
+// AdjustSigmoid changes the contrast of the image using a sigmoidal function and returns the adjusted image.
+// It's a non-linear contrast change useful for photo adjustments as it preserves highlight and shadow detail.
+// The midpoint parameter is the midpoint of contrast that must be between 0 and 1, typically 0.5.
+// The factor parameter indicates how much to increase or decrease the contrast, typically in range (-10, 10).
+// If the factor parameter is positive the image contrast is increased otherwise the contrast is decreased.
+//
+// Examples:
+//
+// dstImage = imaging.AdjustSigmoid(srcImage, 0.5, 3.0) // Increase the contrast.
+// dstImage = imaging.AdjustSigmoid(srcImage, 0.5, -3.0) // Decrease the contrast.
+//
+func AdjustSigmoid(img image.Image, midpoint, factor float64) *image.NRGBA {
+ if factor == 0 {
+ return Clone(img)
+ }
+
+ lut := make([]uint8, 256)
+ a := math.Min(math.Max(midpoint, 0.0), 1.0)
+ b := math.Abs(factor)
+ sig0 := sigmoid(a, b, 0)
+ sig1 := sigmoid(a, b, 1)
+ e := 1.0e-6
+
+ if factor > 0 {
+ for i := 0; i < 256; i++ {
+ x := float64(i) / 255.0
+ sigX := sigmoid(a, b, x)
+ f := (sigX - sig0) / (sig1 - sig0)
+ lut[i] = clamp(f * 255.0)
+ }
+ } else {
+ for i := 0; i < 256; i++ {
+ x := float64(i) / 255.0
+ arg := math.Min(math.Max((sig1-sig0)*x+sig0, e), 1.0-e)
+ f := a - math.Log(1.0/arg-1.0)/b
+ lut[i] = clamp(f * 255.0)
+ }
+ }
+
+ return adjustLUT(img, lut)
+}
+
+func sigmoid(a, b, x float64) float64 {
+ return 1 / (1 + math.Exp(b*(a-x)))
+}
+
+// adjustLUT applies the given lookup table to the colors of the image.
+func adjustLUT(img image.Image, lut []uint8) *image.NRGBA {
+ src := newScanner(img)
+ dst := image.NewNRGBA(image.Rect(0, 0, src.w, src.h))
+ lut = lut[0:256]
+ parallel(0, src.h, func(ys <-chan int) {
+ for y := range ys {
+ i := y * dst.Stride
+ src.scan(0, y, src.w, y+1, dst.Pix[i:i+src.w*4])
+ for x := 0; x < src.w; x++ {
+ d := dst.Pix[i : i+3 : i+3]
+ d[0] = lut[d[0]]
+ d[1] = lut[d[1]]
+ d[2] = lut[d[2]]
+ i += 4
+ }
+ }
+ })
+ return dst
+}
+
+// AdjustFunc applies the fn function to each pixel of the img image and returns the adjusted image.
+//
+// Example:
+//
+// dstImage = imaging.AdjustFunc(
+// srcImage,
+// func(c color.NRGBA) color.NRGBA {
+// // Shift the red channel by 16.
+// r := int(c.R) + 16
+// if r > 255 {
+// r = 255
+// }
+// return color.NRGBA{uint8(r), c.G, c.B, c.A}
+// }
+// )
+//
+func AdjustFunc(img image.Image, fn func(c color.NRGBA) color.NRGBA) *image.NRGBA {
+ src := newScanner(img)
+ dst := image.NewNRGBA(image.Rect(0, 0, src.w, src.h))
+ parallel(0, src.h, func(ys <-chan int) {
+ for y := range ys {
+ i := y * dst.Stride
+ src.scan(0, y, src.w, y+1, dst.Pix[i:i+src.w*4])
+ for x := 0; x < src.w; x++ {
+ d := dst.Pix[i : i+4 : i+4]
+ r := d[0]
+ g := d[1]
+ b := d[2]
+ a := d[3]
+ c := fn(color.NRGBA{r, g, b, a})
+ d[0] = c.R
+ d[1] = c.G
+ d[2] = c.B
+ d[3] = c.A
+ i += 4
+ }
+ }
+ })
+ return dst
+}