diff options
Diffstat (limited to 'vendor/github.com/disintegration/imaging/effects.go')
-rw-r--r-- | vendor/github.com/disintegration/imaging/effects.go | 169 |
1 files changed, 0 insertions, 169 deletions
diff --git a/vendor/github.com/disintegration/imaging/effects.go b/vendor/github.com/disintegration/imaging/effects.go deleted file mode 100644 index 47316b70..00000000 --- a/vendor/github.com/disintegration/imaging/effects.go +++ /dev/null @@ -1,169 +0,0 @@ -package imaging - -import ( - "image" - "math" -) - -func gaussianBlurKernel(x, sigma float64) float64 { - return math.Exp(-(x*x)/(2*sigma*sigma)) / (sigma * math.Sqrt(2*math.Pi)) -} - -// Blur produces a blurred version of the image using a Gaussian function. -// Sigma parameter must be positive and indicates how much the image will be blurred. -// -// Example: -// -// dstImage := imaging.Blur(srcImage, 3.5) -// -func Blur(img image.Image, sigma float64) *image.NRGBA { - if sigma <= 0 { - return Clone(img) - } - - radius := int(math.Ceil(sigma * 3.0)) - kernel := make([]float64, radius+1) - - for i := 0; i <= radius; i++ { - kernel[i] = gaussianBlurKernel(float64(i), sigma) - } - - return blurVertical(blurHorizontal(img, kernel), kernel) -} - -func blurHorizontal(img image.Image, kernel []float64) *image.NRGBA { - src := newScanner(img) - dst := image.NewNRGBA(image.Rect(0, 0, src.w, src.h)) - radius := len(kernel) - 1 - - parallel(0, src.h, func(ys <-chan int) { - scanLine := make([]uint8, src.w*4) - scanLineF := make([]float64, len(scanLine)) - for y := range ys { - src.scan(0, y, src.w, y+1, scanLine) - for i, v := range scanLine { - scanLineF[i] = float64(v) - } - for x := 0; x < src.w; x++ { - min := x - radius - if min < 0 { - min = 0 - } - max := x + radius - if max > src.w-1 { - max = src.w - 1 - } - var r, g, b, a, wsum float64 - for ix := min; ix <= max; ix++ { - i := ix * 4 - weight := kernel[absint(x-ix)] - wsum += weight - s := scanLineF[i : i+4 : i+4] - wa := s[3] * weight - r += s[0] * wa - g += s[1] * wa - b += s[2] * wa - a += wa - } - if a != 0 { - aInv := 1 / a - j := y*dst.Stride + x*4 - d := dst.Pix[j : j+4 : j+4] - d[0] = clamp(r * aInv) - d[1] = clamp(g * aInv) - d[2] = clamp(b * aInv) - d[3] = clamp(a / wsum) - } - } - } - }) - - return dst -} - -func blurVertical(img image.Image, kernel []float64) *image.NRGBA { - src := newScanner(img) - dst := image.NewNRGBA(image.Rect(0, 0, src.w, src.h)) - radius := len(kernel) - 1 - - parallel(0, src.w, func(xs <-chan int) { - scanLine := make([]uint8, src.h*4) - scanLineF := make([]float64, len(scanLine)) - for x := range xs { - src.scan(x, 0, x+1, src.h, scanLine) - for i, v := range scanLine { - scanLineF[i] = float64(v) - } - for y := 0; y < src.h; y++ { - min := y - radius - if min < 0 { - min = 0 - } - max := y + radius - if max > src.h-1 { - max = src.h - 1 - } - var r, g, b, a, wsum float64 - for iy := min; iy <= max; iy++ { - i := iy * 4 - weight := kernel[absint(y-iy)] - wsum += weight - s := scanLineF[i : i+4 : i+4] - wa := s[3] * weight - r += s[0] * wa - g += s[1] * wa - b += s[2] * wa - a += wa - } - if a != 0 { - aInv := 1 / a - j := y*dst.Stride + x*4 - d := dst.Pix[j : j+4 : j+4] - d[0] = clamp(r * aInv) - d[1] = clamp(g * aInv) - d[2] = clamp(b * aInv) - d[3] = clamp(a / wsum) - } - } - } - }) - - return dst -} - -// Sharpen produces a sharpened version of the image. -// Sigma parameter must be positive and indicates how much the image will be sharpened. -// -// Example: -// -// dstImage := imaging.Sharpen(srcImage, 3.5) -// -func Sharpen(img image.Image, sigma float64) *image.NRGBA { - if sigma <= 0 { - return Clone(img) - } - - src := newScanner(img) - dst := image.NewNRGBA(image.Rect(0, 0, src.w, src.h)) - blurred := Blur(img, sigma) - - parallel(0, src.h, func(ys <-chan int) { - scanLine := make([]uint8, src.w*4) - for y := range ys { - src.scan(0, y, src.w, y+1, scanLine) - j := y * dst.Stride - for i := 0; i < src.w*4; i++ { - val := int(scanLine[i])<<1 - int(blurred.Pix[j]) - if val < 0 { - val = 0 - } else if val > 0xff { - val = 0xff - } - dst.Pix[j] = uint8(val) - j++ - } - } - }) - - return dst -} |