From dd94a3df5de6cbb4e3351c4731221d3142b60500 Mon Sep 17 00:00:00 2001
From: Jack <jackdeng@gmail.com>
Date: Wed, 23 Sep 2015 20:00:36 -0700
Subject: add imaging

---
 .../github.com/disintegration/imaging/effects.go   | 187 +++++++++++++++++++++
 1 file changed, 187 insertions(+)
 create mode 100644 Godeps/_workspace/src/github.com/disintegration/imaging/effects.go

(limited to 'Godeps/_workspace/src/github.com/disintegration/imaging/effects.go')

diff --git a/Godeps/_workspace/src/github.com/disintegration/imaging/effects.go b/Godeps/_workspace/src/github.com/disintegration/imaging/effects.go
new file mode 100644
index 000000000..fe92e10a2
--- /dev/null
+++ b/Godeps/_workspace/src/github.com/disintegration/imaging/effects.go
@@ -0,0 +1,187 @@
+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.
+//
+// Usage example:
+//
+//		dstImage := imaging.Blur(srcImage, 3.5)
+//
+func Blur(img image.Image, sigma float64) *image.NRGBA {
+	if sigma <= 0 {
+		// sigma parameter must be positive!
+		return Clone(img)
+	}
+
+	src := toNRGBA(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)
+	}
+
+	var dst *image.NRGBA
+	dst = blurHorizontal(src, kernel)
+	dst = blurVertical(dst, kernel)
+
+	return dst
+}
+
+func blurHorizontal(src *image.NRGBA, kernel []float64) *image.NRGBA {
+	radius := len(kernel) - 1
+	width := src.Bounds().Max.X
+	height := src.Bounds().Max.Y
+
+	dst := image.NewNRGBA(image.Rect(0, 0, width, height))
+
+	parallel(width, func(partStart, partEnd int) {
+		for x := partStart; x < partEnd; x++ {
+			start := x - radius
+			if start < 0 {
+				start = 0
+			}
+
+			end := x + radius
+			if end > width-1 {
+				end = width - 1
+			}
+
+			weightSum := 0.0
+			for ix := start; ix <= end; ix++ {
+				weightSum += kernel[absint(x-ix)]
+			}
+
+			for y := 0; y < height; y++ {
+
+				r, g, b, a := 0.0, 0.0, 0.0, 0.0
+				for ix := start; ix <= end; ix++ {
+					weight := kernel[absint(x-ix)]
+					i := y*src.Stride + ix*4
+					r += float64(src.Pix[i+0]) * weight
+					g += float64(src.Pix[i+1]) * weight
+					b += float64(src.Pix[i+2]) * weight
+					a += float64(src.Pix[i+3]) * weight
+				}
+
+				r = math.Min(math.Max(r/weightSum, 0.0), 255.0)
+				g = math.Min(math.Max(g/weightSum, 0.0), 255.0)
+				b = math.Min(math.Max(b/weightSum, 0.0), 255.0)
+				a = math.Min(math.Max(a/weightSum, 0.0), 255.0)
+
+				j := y*dst.Stride + x*4
+				dst.Pix[j+0] = uint8(r + 0.5)
+				dst.Pix[j+1] = uint8(g + 0.5)
+				dst.Pix[j+2] = uint8(b + 0.5)
+				dst.Pix[j+3] = uint8(a + 0.5)
+
+			}
+		}
+	})
+
+	return dst
+}
+
+func blurVertical(src *image.NRGBA, kernel []float64) *image.NRGBA {
+	radius := len(kernel) - 1
+	width := src.Bounds().Max.X
+	height := src.Bounds().Max.Y
+
+	dst := image.NewNRGBA(image.Rect(0, 0, width, height))
+
+	parallel(height, func(partStart, partEnd int) {
+		for y := partStart; y < partEnd; y++ {
+			start := y - radius
+			if start < 0 {
+				start = 0
+			}
+
+			end := y + radius
+			if end > height-1 {
+				end = height - 1
+			}
+
+			weightSum := 0.0
+			for iy := start; iy <= end; iy++ {
+				weightSum += kernel[absint(y-iy)]
+			}
+
+			for x := 0; x < width; x++ {
+
+				r, g, b, a := 0.0, 0.0, 0.0, 0.0
+				for iy := start; iy <= end; iy++ {
+					weight := kernel[absint(y-iy)]
+					i := iy*src.Stride + x*4
+					r += float64(src.Pix[i+0]) * weight
+					g += float64(src.Pix[i+1]) * weight
+					b += float64(src.Pix[i+2]) * weight
+					a += float64(src.Pix[i+3]) * weight
+				}
+
+				r = math.Min(math.Max(r/weightSum, 0.0), 255.0)
+				g = math.Min(math.Max(g/weightSum, 0.0), 255.0)
+				b = math.Min(math.Max(b/weightSum, 0.0), 255.0)
+				a = math.Min(math.Max(a/weightSum, 0.0), 255.0)
+
+				j := y*dst.Stride + x*4
+				dst.Pix[j+0] = uint8(r + 0.5)
+				dst.Pix[j+1] = uint8(g + 0.5)
+				dst.Pix[j+2] = uint8(b + 0.5)
+				dst.Pix[j+3] = uint8(a + 0.5)
+
+			}
+		}
+	})
+
+	return dst
+}
+
+// Sharpen produces a sharpened version of the image.
+// Sigma parameter must be positive and indicates how much the image will be sharpened.
+//
+// Usage example:
+//
+//		dstImage := imaging.Sharpen(srcImage, 3.5)
+//
+func Sharpen(img image.Image, sigma float64) *image.NRGBA {
+	if sigma <= 0 {
+		// sigma parameter must be positive!
+		return Clone(img)
+	}
+
+	src := toNRGBA(img)
+	blurred := Blur(img, sigma)
+
+	width := src.Bounds().Max.X
+	height := src.Bounds().Max.Y
+	dst := image.NewNRGBA(image.Rect(0, 0, width, height))
+
+	parallel(height, func(partStart, partEnd int) {
+		for y := partStart; y < partEnd; y++ {
+			for x := 0; x < width; x++ {
+				i := y*src.Stride + x*4
+				for j := 0; j < 4; j++ {
+					k := i + j
+					val := int(src.Pix[k]) + (int(src.Pix[k]) - int(blurred.Pix[k]))
+					if val < 0 {
+						val = 0
+					} else if val > 255 {
+						val = 255
+					}
+					dst.Pix[k] = uint8(val)
+				}
+			}
+		}
+	})
+
+	return dst
+}
-- 
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