clone project

.gitignore

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+.idea

AUTHORS

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+# This is the official list of Graphics-Go authors for copyright purposes.
+# This file is distinct from the CONTRIBUTORS files.
+# See the latter for an explanation.
+
+# Names should be added to this file as
+#	Name or Organization <email address>
+# The email address is not required for organizations.
+
+# Please keep the list sorted.
+
+Google Inc.

CONTRIBUTORS

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+# This is the official list of people who can contribute
+# (and typically have contributed) code to the Graphics-Go repository.
+# The AUTHORS file lists the copyright holders; this file
+# lists people.  For example, Google employees are listed here
+# but not in AUTHORS, because Google holds the copyright.
+#
+# The submission process automatically checks to make sure
+# that people submitting code are listed in this file (by email address).
+#
+# Names should be added to this file only after verifying that
+# the individual or the individual's organization has agreed to
+# the appropriate Contributor License Agreement, found here:
+#
+#     http://code.google.com/legal/individual-cla-v1.0.html
+#     http://code.google.com/legal/corporate-cla-v1.0.html
+#
+# The agreement for individuals can be filled out on the web.
+#
+# When adding J Random Contributor's name to this file,
+# either J's name or J's organization's name should be
+# added to the AUTHORS file, depending on whether the
+# individual or corporate CLA was used.
+
+# Names should be added to this file like so:
+#     Name <email address>
+
+# Please keep the list sorted.
+
+David Crawshaw <[email protected]>
+Johan Euphrosine <[email protected]>
+Nigel Tao <[email protected]>

LICENSE

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+Copyright (c) 2011 The Graphics-Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Makefile

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+# 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.
+
+include $(GOROOT)/src/Make.inc
+
+all: install
+
+# The order matters: earlier packages may not depend on later ones.
+DIRS=\
+	graphics
+
+test:
+	cd graphics; GOMAXPROCS=2 gomake test
+
+bench:
+	cd graphics; GOMAXPROCS=2 gomake bench
+
+install clean nuke:
+	for dir in $(DIRS); do \
+		$(MAKE) -C $$dir $@ || exit 1; \
+	done

README

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+This is a Graphics library for the Go programming language.
+
+Unless otherwise noted, the graphics-go source files are distributed
+under the BSD-style license found in the LICENSE file.
+
+Contributions should follow the same procedure as for the Go project:
+http://golang.org/doc/contribute.html

go.mod

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+module code.google.com/p/graphics-go
+
+go 1.16

graphics/Makefile

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+# 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.
+
+include $(GOROOT)/src/Make.inc
+
+TARG=code.google.com/p/graphics-go/graphics
+GOFILES=\
+	affine.go\
+	blur.go\
+	rotate.go\
+	scale.go\
+	thumbnail.go\
+
+include $(GOROOT)/src/Make.pkg

graphics/affine.go

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+// 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/interp"
+	"errors"
+	"image"
+	"image/draw"
+	"math"
+)
+
+// I is the identity Affine transform matrix.
+var I = Affine{
+	1, 0, 0,
+	0, 1, 0,
+	0, 0, 1,
+}
+
+// Affine is a 3x3 2D affine transform matrix.
+// M(i,j) is Affine[i*3+j].
+type Affine [9]float64
+
+// Mul returns the multiplication of two affine transform matrices.
+func (a Affine) Mul(b Affine) Affine {
+	return Affine{
+		a[0]*b[0] + a[1]*b[3] + a[2]*b[6],
+		a[0]*b[1] + a[1]*b[4] + a[2]*b[7],
+		a[0]*b[2] + a[1]*b[5] + a[2]*b[8],
+		a[3]*b[0] + a[4]*b[3] + a[5]*b[6],
+		a[3]*b[1] + a[4]*b[4] + a[5]*b[7],
+		a[3]*b[2] + a[4]*b[5] + a[5]*b[8],
+		a[6]*b[0] + a[7]*b[3] + a[8]*b[6],
+		a[6]*b[1] + a[7]*b[4] + a[8]*b[7],
+		a[6]*b[2] + a[7]*b[5] + a[8]*b[8],
+	}
+}
+
+func (a Affine) transformRGBA(dst *image.RGBA, src *image.RGBA, i interp.RGBA) error {
+	srcb := src.Bounds()
+	b := dst.Bounds()
+	for y := b.Min.Y; y < b.Max.Y; y++ {
+		for x := b.Min.X; x < b.Max.X; x++ {
+			sx, sy := a.pt(x, y)
+			if inBounds(srcb, sx, sy) {
+				c := i.RGBA(src, sx, sy)
+				off := (y-dst.Rect.Min.Y)*dst.Stride + (x-dst.Rect.Min.X)*4
+				dst.Pix[off+0] = c.R
+				dst.Pix[off+1] = c.G
+				dst.Pix[off+2] = c.B
+				dst.Pix[off+3] = c.A
+			}
+		}
+	}
+	return nil
+}
+
+// Transform applies the affine transform to src and produces dst.
+func (a Affine) Transform(dst draw.Image, src image.Image, i interp.Interp) error {
+	if dst == nil {
+		return errors.New("graphics: dst is nil")
+	}
+	if src == nil {
+		return errors.New("graphics: src is nil")
+	}
+
+	// RGBA fast path.
+	dstRGBA, dstOk := dst.(*image.RGBA)
+	srcRGBA, srcOk := src.(*image.RGBA)
+	interpRGBA, interpOk := i.(interp.RGBA)
+	if dstOk && srcOk && interpOk {
+		return a.transformRGBA(dstRGBA, srcRGBA, interpRGBA)
+	}
+
+	srcb := src.Bounds()
+	b := dst.Bounds()
+	for y := b.Min.Y; y < b.Max.Y; y++ {
+		for x := b.Min.X; x < b.Max.X; x++ {
+			sx, sy := a.pt(x, y)
+			if inBounds(srcb, sx, sy) {
+				dst.Set(x, y, i.Interp(src, sx, sy))
+			}
+		}
+	}
+	return nil
+}
+
+func inBounds(b image.Rectangle, x, y float64) bool {
+	if x < float64(b.Min.X) || x >= float64(b.Max.X) {
+		return false
+	}
+	if y < float64(b.Min.Y) || y >= float64(b.Max.Y) {
+		return false
+	}
+	return true
+}
+
+func (a Affine) pt(x0, y0 int) (x1, y1 float64) {
+	fx := float64(x0) + 0.5
+	fy := float64(y0) + 0.5
+	x1 = fx*a[0] + fy*a[1] + a[2]
+	y1 = fx*a[3] + fy*a[4] + a[5]
+	return x1, y1
+}
+
+// TransformCenter applies the affine transform to src and produces dst.
+// Equivalent to
+//   a.CenterFit(dst, src).Transform(dst, src, i).
+func (a Affine) TransformCenter(dst draw.Image, src image.Image, i interp.Interp) error {
+	if dst == nil {
+		return errors.New("graphics: dst is nil")
+	}
+	if src == nil {
+		return errors.New("graphics: src is nil")
+	}
+
+	return a.CenterFit(dst.Bounds(), src.Bounds()).Transform(dst, src, i)
+}
+
+// Scale produces a scaling transform of factors x and y.
+func (a Affine) Scale(x, y float64) Affine {
+	return a.Mul(Affine{
+		1 / x, 0, 0,
+		0, 1 / y, 0,
+		0, 0, 1,
+	})
+}
+
+// Rotate produces a clockwise rotation transform of angle, in radians.
+func (a Affine) Rotate(angle float64) Affine {
+	s, c := math.Sincos(angle)
+	return a.Mul(Affine{
+		+c, +s, +0,
+		-s, +c, +0,
+		+0, +0, +1,
+	})
+}
+
+// Shear produces a shear transform by the slopes x and y.
+func (a Affine) Shear(x, y float64) Affine {
+	d := 1 - x*y
+	return a.Mul(Affine{
+		+1 / d, -x / d, 0,
+		-y / d, +1 / d, 0,
+		0, 0, 1,
+	})
+}
+
+// Translate produces a translation transform with pixel distances x and y.
+func (a Affine) Translate(x, y float64) Affine {
+	return a.Mul(Affine{
+		1, 0, -x,
+		0, 1, -y,
+		0, 0, +1,
+	})
+}
+
+// Center produces the affine transform, centered around the provided point.
+func (a Affine) Center(x, y float64) Affine {
+	return I.Translate(-x, -y).Mul(a).Translate(x, y)
+}
+
+// CenterFit produces the affine transform, centered around the rectangles.
+// It is equivalent to
+//   I.Translate(-<center of src>).Mul(a).Translate(<center of dst>)
+func (a Affine) CenterFit(dst, src image.Rectangle) Affine {
+	dx := float64(dst.Min.X) + float64(dst.Dx())/2
+	dy := float64(dst.Min.Y) + float64(dst.Dy())/2
+	sx := float64(src.Min.X) + float64(src.Dx())/2
+	sy := float64(src.Min.Y) + float64(src.Dy())/2
+	return I.Translate(-sx, -sy).Mul(a).Translate(dx, dy)
+}

graphics/blur.go

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+// 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,
+	})
+}