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Diffstat (limited to 'vendor/golang.org/x/image/draw/scale.go')
-rw-r--r--vendor/golang.org/x/image/draw/scale.go527
1 files changed, 0 insertions, 527 deletions
diff --git a/vendor/golang.org/x/image/draw/scale.go b/vendor/golang.org/x/image/draw/scale.go
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index 98ab404..0000000
--- a/vendor/golang.org/x/image/draw/scale.go
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@@ -1,527 +0,0 @@
-// Copyright 2015 The 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.
-
-//go:generate go run gen.go
-
-package draw
-
-import (
- "image"
- "image/color"
- "math"
- "sync"
-
- "golang.org/x/image/math/f64"
-)
-
-// Copy copies the part of the source image defined by src and sr and writes
-// the result of a Porter-Duff composition to the part of the destination image
-// defined by dst and the translation of sr so that sr.Min translates to dp.
-func Copy(dst Image, dp image.Point, src image.Image, sr image.Rectangle, op Op, opts *Options) {
- var o Options
- if opts != nil {
- o = *opts
- }
- dr := sr.Add(dp.Sub(sr.Min))
- if o.DstMask == nil {
- DrawMask(dst, dr, src, sr.Min, o.SrcMask, o.SrcMaskP.Add(sr.Min), op)
- } else {
- NearestNeighbor.Scale(dst, dr, src, sr, op, opts)
- }
-}
-
-// Scaler scales the part of the source image defined by src and sr and writes
-// the result of a Porter-Duff composition to the part of the destination image
-// defined by dst and dr.
-//
-// A Scaler is safe to use concurrently.
-type Scaler interface {
- Scale(dst Image, dr image.Rectangle, src image.Image, sr image.Rectangle, op Op, opts *Options)
-}
-
-// Transformer transforms the part of the source image defined by src and sr
-// and writes the result of a Porter-Duff composition to the part of the
-// destination image defined by dst and the affine transform m applied to sr.
-//
-// For example, if m is the matrix
-//
-// m00 m01 m02
-// m10 m11 m12
-//
-// then the src-space point (sx, sy) maps to the dst-space point
-// (m00*sx + m01*sy + m02, m10*sx + m11*sy + m12).
-//
-// A Transformer is safe to use concurrently.
-type Transformer interface {
- Transform(dst Image, m f64.Aff3, src image.Image, sr image.Rectangle, op Op, opts *Options)
-}
-
-// Options are optional parameters to Copy, Scale and Transform.
-//
-// A nil *Options means to use the default (zero) values of each field.
-type Options struct {
- // Masks limit what parts of the dst image are drawn to and what parts of
- // the src image are drawn from.
- //
- // A dst or src mask image having a zero alpha (transparent) pixel value in
- // the respective coordinate space means that that dst pixel is entirely
- // unaffected or that src pixel is considered transparent black. A full
- // alpha (opaque) value means that the dst pixel is maximally affected or
- // the src pixel contributes maximally. The default values, nil, are
- // equivalent to fully opaque, infinitely large mask images.
- //
- // The DstMask is otherwise known as a clip mask, and its pixels map 1:1 to
- // the dst image's pixels. DstMaskP in DstMask space corresponds to
- // image.Point{X:0, Y:0} in dst space. For example, when limiting
- // repainting to a 'dirty rectangle', use that image.Rectangle and a zero
- // image.Point as the DstMask and DstMaskP.
- //
- // The SrcMask's pixels map 1:1 to the src image's pixels. SrcMaskP in
- // SrcMask space corresponds to image.Point{X:0, Y:0} in src space. For
- // example, when drawing font glyphs in a uniform color, use an
- // *image.Uniform as the src, and use the glyph atlas image and the
- // per-glyph offset as SrcMask and SrcMaskP:
- // Copy(dst, dp, image.NewUniform(color), image.Rect(0, 0, glyphWidth, glyphHeight), &Options{
- // SrcMask: glyphAtlas,
- // SrcMaskP: glyphOffset,
- // })
- DstMask image.Image
- DstMaskP image.Point
- SrcMask image.Image
- SrcMaskP image.Point
-
- // TODO: a smooth vs sharp edges option, for arbitrary rotations?
-}
-
-// Interpolator is an interpolation algorithm, when dst and src pixels don't
-// have a 1:1 correspondence.
-//
-// Of the interpolators provided by this package:
-// - NearestNeighbor is fast but usually looks worst.
-// - CatmullRom is slow but usually looks best.
-// - ApproxBiLinear has reasonable speed and quality.
-//
-// The time taken depends on the size of dr. For kernel interpolators, the
-// speed also depends on the size of sr, and so are often slower than
-// non-kernel interpolators, especially when scaling down.
-type Interpolator interface {
- Scaler
- Transformer
-}
-
-// Kernel is an interpolator that blends source pixels weighted by a symmetric
-// kernel function.
-type Kernel struct {
- // Support is the kernel support and must be >= 0. At(t) is assumed to be
- // zero when t >= Support.
- Support float64
- // At is the kernel function. It will only be called with t in the
- // range [0, Support).
- At func(t float64) float64
-}
-
-// Scale implements the Scaler interface.
-func (q *Kernel) Scale(dst Image, dr image.Rectangle, src image.Image, sr image.Rectangle, op Op, opts *Options) {
- q.newScaler(dr.Dx(), dr.Dy(), sr.Dx(), sr.Dy(), false).Scale(dst, dr, src, sr, op, opts)
-}
-
-// NewScaler returns a Scaler that is optimized for scaling multiple times with
-// the same fixed destination and source width and height.
-func (q *Kernel) NewScaler(dw, dh, sw, sh int) Scaler {
- return q.newScaler(dw, dh, sw, sh, true)
-}
-
-func (q *Kernel) newScaler(dw, dh, sw, sh int, usePool bool) Scaler {
- z := &kernelScaler{
- kernel: q,
- dw: int32(dw),
- dh: int32(dh),
- sw: int32(sw),
- sh: int32(sh),
- horizontal: newDistrib(q, int32(dw), int32(sw)),
- vertical: newDistrib(q, int32(dh), int32(sh)),
- }
- if usePool {
- z.pool.New = func() interface{} {
- tmp := z.makeTmpBuf()
- return &tmp
- }
- }
- return z
-}
-
-var (
- // NearestNeighbor is the nearest neighbor interpolator. It is very fast,
- // but usually gives very low quality results. When scaling up, the result
- // will look 'blocky'.
- NearestNeighbor = Interpolator(nnInterpolator{})
-
- // ApproxBiLinear is a mixture of the nearest neighbor and bi-linear
- // interpolators. It is fast, but usually gives medium quality results.
- //
- // It implements bi-linear interpolation when upscaling and a bi-linear
- // blend of the 4 nearest neighbor pixels when downscaling. This yields
- // nicer quality than nearest neighbor interpolation when upscaling, but
- // the time taken is independent of the number of source pixels, unlike the
- // bi-linear interpolator. When downscaling a large image, the performance
- // difference can be significant.
- ApproxBiLinear = Interpolator(ablInterpolator{})
-
- // BiLinear is the tent kernel. It is slow, but usually gives high quality
- // results.
- BiLinear = &Kernel{1, func(t float64) float64 {
- return 1 - t
- }}
-
- // CatmullRom is the Catmull-Rom kernel. It is very slow, but usually gives
- // very high quality results.
- //
- // It is an instance of the more general cubic BC-spline kernel with parameters
- // B=0 and C=0.5. See Mitchell and Netravali, "Reconstruction Filters in
- // Computer Graphics", Computer Graphics, Vol. 22, No. 4, pp. 221-228.
- CatmullRom = &Kernel{2, func(t float64) float64 {
- if t < 1 {
- return (1.5*t-2.5)*t*t + 1
- }
- return ((-0.5*t+2.5)*t-4)*t + 2
- }}
-
- // TODO: a Kaiser-Bessel kernel?
-)
-
-type nnInterpolator struct{}
-
-type ablInterpolator struct{}
-
-type kernelScaler struct {
- kernel *Kernel
- dw, dh, sw, sh int32
- horizontal, vertical distrib
- pool sync.Pool
-}
-
-func (z *kernelScaler) makeTmpBuf() [][4]float64 {
- return make([][4]float64, z.dw*z.sh)
-}
-
-// source is a range of contribs, their inverse total weight, and that ITW
-// divided by 0xffff.
-type source struct {
- i, j int32
- invTotalWeight float64
- invTotalWeightFFFF float64
-}
-
-// contrib is the weight of a column or row.
-type contrib struct {
- coord int32
- weight float64
-}
-
-// distrib measures how source pixels are distributed over destination pixels.
-type distrib struct {
- // sources are what contribs each column or row in the source image owns,
- // and the total weight of those contribs.
- sources []source
- // contribs are the contributions indexed by sources[s].i and sources[s].j.
- contribs []contrib
-}
-
-// newDistrib returns a distrib that distributes sw source columns (or rows)
-// over dw destination columns (or rows).
-func newDistrib(q *Kernel, dw, sw int32) distrib {
- scale := float64(sw) / float64(dw)
- halfWidth, kernelArgScale := q.Support, 1.0
- // When shrinking, broaden the effective kernel support so that we still
- // visit every source pixel.
- if scale > 1 {
- halfWidth *= scale
- kernelArgScale = 1 / scale
- }
-
- // Make the sources slice, one source for each column or row, and temporarily
- // appropriate its elements' fields so that invTotalWeight is the scaled
- // coordinate of the source column or row, and i and j are the lower and
- // upper bounds of the range of destination columns or rows affected by the
- // source column or row.
- n, sources := int32(0), make([]source, dw)
- for x := range sources {
- center := (float64(x)+0.5)*scale - 0.5
- i := int32(math.Floor(center - halfWidth))
- if i < 0 {
- i = 0
- }
- j := int32(math.Ceil(center + halfWidth))
- if j > sw {
- j = sw
- if j < i {
- j = i
- }
- }
- sources[x] = source{i: i, j: j, invTotalWeight: center}
- n += j - i
- }
-
- contribs := make([]contrib, 0, n)
- for k, b := range sources {
- totalWeight := 0.0
- l := int32(len(contribs))
- for coord := b.i; coord < b.j; coord++ {
- t := abs((b.invTotalWeight - float64(coord)) * kernelArgScale)
- if t >= q.Support {
- continue
- }
- weight := q.At(t)
- if weight == 0 {
- continue
- }
- totalWeight += weight
- contribs = append(contribs, contrib{coord, weight})
- }
- totalWeight = 1 / totalWeight
- sources[k] = source{
- i: l,
- j: int32(len(contribs)),
- invTotalWeight: totalWeight,
- invTotalWeightFFFF: totalWeight / 0xffff,
- }
- }
-
- return distrib{sources, contribs}
-}
-
-// abs is like math.Abs, but it doesn't care about negative zero, infinities or
-// NaNs.
-func abs(f float64) float64 {
- if f < 0 {
- f = -f
- }
- return f
-}
-
-// ftou converts the range [0.0, 1.0] to [0, 0xffff].
-func ftou(f float64) uint16 {
- i := int32(0xffff*f + 0.5)
- if i > 0xffff {
- return 0xffff
- }
- if i > 0 {
- return uint16(i)
- }
- return 0
-}
-
-// fffftou converts the range [0.0, 65535.0] to [0, 0xffff].
-func fffftou(f float64) uint16 {
- i := int32(f + 0.5)
- if i > 0xffff {
- return 0xffff
- }
- if i > 0 {
- return uint16(i)
- }
- return 0
-}
-
-// invert returns the inverse of m.
-//
-// TODO: move this into the f64 package, once we work out the convention for
-// matrix methods in that package: do they modify the receiver, take a dst
-// pointer argument, or return a new value?
-func invert(m *f64.Aff3) f64.Aff3 {
- m00 := +m[3*1+1]
- m01 := -m[3*0+1]
- m02 := +m[3*1+2]*m[3*0+1] - m[3*1+1]*m[3*0+2]
- m10 := -m[3*1+0]
- m11 := +m[3*0+0]
- m12 := +m[3*1+0]*m[3*0+2] - m[3*1+2]*m[3*0+0]
-
- det := m00*m11 - m10*m01
-
- return f64.Aff3{
- m00 / det,
- m01 / det,
- m02 / det,
- m10 / det,
- m11 / det,
- m12 / det,
- }
-}
-
-func matMul(p, q *f64.Aff3) f64.Aff3 {
- return f64.Aff3{
- p[3*0+0]*q[3*0+0] + p[3*0+1]*q[3*1+0],
- p[3*0+0]*q[3*0+1] + p[3*0+1]*q[3*1+1],
- p[3*0+0]*q[3*0+2] + p[3*0+1]*q[3*1+2] + p[3*0+2],
- p[3*1+0]*q[3*0+0] + p[3*1+1]*q[3*1+0],
- p[3*1+0]*q[3*0+1] + p[3*1+1]*q[3*1+1],
- p[3*1+0]*q[3*0+2] + p[3*1+1]*q[3*1+2] + p[3*1+2],
- }
-}
-
-// transformRect returns a rectangle dr that contains sr transformed by s2d.
-func transformRect(s2d *f64.Aff3, sr *image.Rectangle) (dr image.Rectangle) {
- ps := [...]image.Point{
- {sr.Min.X, sr.Min.Y},
- {sr.Max.X, sr.Min.Y},
- {sr.Min.X, sr.Max.Y},
- {sr.Max.X, sr.Max.Y},
- }
- for i, p := range ps {
- sxf := float64(p.X)
- syf := float64(p.Y)
- dx := int(math.Floor(s2d[0]*sxf + s2d[1]*syf + s2d[2]))
- dy := int(math.Floor(s2d[3]*sxf + s2d[4]*syf + s2d[5]))
-
- // The +1 adjustments below are because an image.Rectangle is inclusive
- // on the low end but exclusive on the high end.
-
- if i == 0 {
- dr = image.Rectangle{
- Min: image.Point{dx + 0, dy + 0},
- Max: image.Point{dx + 1, dy + 1},
- }
- continue
- }
-
- if dr.Min.X > dx {
- dr.Min.X = dx
- }
- dx++
- if dr.Max.X < dx {
- dr.Max.X = dx
- }
-
- if dr.Min.Y > dy {
- dr.Min.Y = dy
- }
- dy++
- if dr.Max.Y < dy {
- dr.Max.Y = dy
- }
- }
- return dr
-}
-
-func clipAffectedDestRect(adr image.Rectangle, dstMask image.Image, dstMaskP image.Point) (image.Rectangle, image.Image) {
- if dstMask == nil {
- return adr, nil
- }
- // TODO: enable this fast path once Go 1.5 is released, where an
- // image.Rectangle implements image.Image.
- // if r, ok := dstMask.(image.Rectangle); ok {
- // return adr.Intersect(r.Sub(dstMaskP)), nil
- // }
- // TODO: clip to dstMask.Bounds() if the color model implies that out-of-bounds means 0 alpha?
- return adr, dstMask
-}
-
-func transform_Uniform(dst Image, dr, adr image.Rectangle, d2s *f64.Aff3, src *image.Uniform, sr image.Rectangle, bias image.Point, op Op) {
- switch op {
- case Over:
- switch dst := dst.(type) {
- case *image.RGBA:
- pr, pg, pb, pa := src.C.RGBA()
- pa1 := (0xffff - pa) * 0x101
-
- for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
- dyf := float64(dr.Min.Y+int(dy)) + 0.5
- d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
- for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx, d = dx+1, d+4 {
- dxf := float64(dr.Min.X+int(dx)) + 0.5
- sx0 := int(d2s[0]*dxf+d2s[1]*dyf+d2s[2]) + bias.X
- sy0 := int(d2s[3]*dxf+d2s[4]*dyf+d2s[5]) + bias.Y
- if !(image.Point{sx0, sy0}).In(sr) {
- continue
- }
- dst.Pix[d+0] = uint8((uint32(dst.Pix[d+0])*pa1/0xffff + pr) >> 8)
- dst.Pix[d+1] = uint8((uint32(dst.Pix[d+1])*pa1/0xffff + pg) >> 8)
- dst.Pix[d+2] = uint8((uint32(dst.Pix[d+2])*pa1/0xffff + pb) >> 8)
- dst.Pix[d+3] = uint8((uint32(dst.Pix[d+3])*pa1/0xffff + pa) >> 8)
- }
- }
-
- default:
- pr, pg, pb, pa := src.C.RGBA()
- pa1 := 0xffff - pa
- dstColorRGBA64 := &color.RGBA64{}
- dstColor := color.Color(dstColorRGBA64)
-
- for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
- dyf := float64(dr.Min.Y+int(dy)) + 0.5
- for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
- dxf := float64(dr.Min.X+int(dx)) + 0.5
- sx0 := int(d2s[0]*dxf+d2s[1]*dyf+d2s[2]) + bias.X
- sy0 := int(d2s[3]*dxf+d2s[4]*dyf+d2s[5]) + bias.Y
- if !(image.Point{sx0, sy0}).In(sr) {
- continue
- }
- qr, qg, qb, qa := dst.At(dr.Min.X+int(dx), dr.Min.Y+int(dy)).RGBA()
- dstColorRGBA64.R = uint16(qr*pa1/0xffff + pr)
- dstColorRGBA64.G = uint16(qg*pa1/0xffff + pg)
- dstColorRGBA64.B = uint16(qb*pa1/0xffff + pb)
- dstColorRGBA64.A = uint16(qa*pa1/0xffff + pa)
- dst.Set(dr.Min.X+int(dx), dr.Min.Y+int(dy), dstColor)
- }
- }
- }
-
- case Src:
- switch dst := dst.(type) {
- case *image.RGBA:
- pr, pg, pb, pa := src.C.RGBA()
- pr8 := uint8(pr >> 8)
- pg8 := uint8(pg >> 8)
- pb8 := uint8(pb >> 8)
- pa8 := uint8(pa >> 8)
-
- for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
- dyf := float64(dr.Min.Y+int(dy)) + 0.5
- d := dst.PixOffset(dr.Min.X+adr.Min.X, dr.Min.Y+int(dy))
- for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx, d = dx+1, d+4 {
- dxf := float64(dr.Min.X+int(dx)) + 0.5
- sx0 := int(d2s[0]*dxf+d2s[1]*dyf+d2s[2]) + bias.X
- sy0 := int(d2s[3]*dxf+d2s[4]*dyf+d2s[5]) + bias.Y
- if !(image.Point{sx0, sy0}).In(sr) {
- continue
- }
- dst.Pix[d+0] = pr8
- dst.Pix[d+1] = pg8
- dst.Pix[d+2] = pb8
- dst.Pix[d+3] = pa8
- }
- }
-
- default:
- pr, pg, pb, pa := src.C.RGBA()
- dstColorRGBA64 := &color.RGBA64{
- uint16(pr),
- uint16(pg),
- uint16(pb),
- uint16(pa),
- }
- dstColor := color.Color(dstColorRGBA64)
-
- for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
- dyf := float64(dr.Min.Y+int(dy)) + 0.5
- for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx++ {
- dxf := float64(dr.Min.X+int(dx)) + 0.5
- sx0 := int(d2s[0]*dxf+d2s[1]*dyf+d2s[2]) + bias.X
- sy0 := int(d2s[3]*dxf+d2s[4]*dyf+d2s[5]) + bias.Y
- if !(image.Point{sx0, sy0}).In(sr) {
- continue
- }
- dst.Set(dr.Min.X+int(dx), dr.Min.Y+int(dy), dstColor)
- }
- }
- }
- }
-}
-
-func opaque(m image.Image) bool {
- o, ok := m.(interface {
- Opaque() bool
- })
- return ok && o.Opaque()
-}