1 files changed, 68 insertions, 0 deletions
diff --git a/Godeps/_workspace/src/code.google.com/p/graphics-go/graphics/blur.go b/Godeps/_workspace/src/code.google.com/p/graphics-go/graphics/blur.go
new file mode 100644
index 000000000..9a54d5ad5
--- /dev/null
+++ b/Godeps/_workspace/src/code.google.com/p/graphics-go/graphics/blur.go
@@ -0,0 +1,68 @@
+// Copyright 2011 The Graphics-Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package graphics
+
+import (
+	"code.google.com/p/graphics-go/graphics/convolve"
+	"errors"
+	"image"
+	"image/draw"
+	"math"
+)
+
+// DefaultStdDev is the default blurring parameter.
+var DefaultStdDev = 0.5
+
+// BlurOptions are the blurring parameters.
+// StdDev is the standard deviation of the normal, higher is blurrier.
+// Size is the size of the kernel. If zero, it is set to Ceil(6 * StdDev).
+type BlurOptions struct {
+	StdDev float64
+	Size   int
+}
+
+// Blur produces a blurred version of the image, using a Gaussian blur.
+func Blur(dst draw.Image, src image.Image, opt *BlurOptions) error {
+	if dst == nil {
+		return errors.New("graphics: dst is nil")
+	}
+	if src == nil {
+		return errors.New("graphics: src is nil")
+	}
+
+	sd := DefaultStdDev
+	size := 0
+
+	if opt != nil {
+		sd = opt.StdDev
+		size = opt.Size
+	}
+
+	if size < 1 {
+		size = int(math.Ceil(sd * 6))
+	}
+
+	kernel := make([]float64, 2*size+1)
+	for i := 0; i <= size; i++ {
+		x := float64(i) / sd
+		x = math.Pow(1/math.SqrtE, x*x)
+		kernel[size-i] = x
+		kernel[size+i] = x
+	}
+
+	// Normalize the weights to sum to 1.0.
+	kSum := 0.0
+	for _, k := range kernel {
+		kSum += k
+	}
+	for i, k := range kernel {
+		kernel[i] = k / kSum
+	}
+
+	return convolve.Convolve(dst, src, &convolve.SeparableKernel{
+		X: kernel,
+		Y: kernel,
+	})
+}