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Diffstat (limited to 'vendor/github.com/disintegration/imaging/adjust.go')
| -rw-r--r-- | vendor/github.com/disintegration/imaging/adjust.go | 222 |
1 files changed, 0 insertions, 222 deletions
diff --git a/vendor/github.com/disintegration/imaging/adjust.go b/vendor/github.com/disintegration/imaging/adjust.go deleted file mode 100644 index fb3a9ce..0000000 --- a/vendor/github.com/disintegration/imaging/adjust.go +++ /dev/null @@ -1,222 +0,0 @@ -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++ { - r := dst.Pix[i+0] - g := dst.Pix[i+1] - b := dst.Pix[i+2] - f := 0.299*float64(r) + 0.587*float64(g) + 0.114*float64(b) - y := uint8(f + 0.5) - dst.Pix[i+0] = y - dst.Pix[i+1] = y - dst.Pix[i+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++ { - dst.Pix[i+0] = 255 - dst.Pix[i+0] - dst.Pix[i+1] = 255 - dst.Pix[i+1] - dst.Pix[i+2] = 255 - dst.Pix[i+2] - i += 4 - } - } - }) - return dst -} - -// 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++ { - if 0 <= v && v <= 1 { - lut[i] = clamp((0.5 + (float64(i)/255.0-0.5)*v) * 255.0) - } else if 1 < v && v < 2 { - lut[i] = clamp((0.5 + (float64(i)/255.0-0.5)*(1/(2.0-v))) * 255.0) - } else { - 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)) - 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++ { - dst.Pix[i+0] = lut[dst.Pix[i+0]] - dst.Pix[i+1] = lut[dst.Pix[i+1]] - dst.Pix[i+2] = lut[dst.Pix[i+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++ { - r := dst.Pix[i+0] - g := dst.Pix[i+1] - b := dst.Pix[i+2] - a := dst.Pix[i+3] - c := fn(color.NRGBA{r, g, b, a}) - dst.Pix[i+0] = c.R - dst.Pix[i+1] = c.G - dst.Pix[i+2] = c.B - dst.Pix[i+3] = c.A - i += 4 - } - } - }) - return dst -} |