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author | Christopher Speller <crspeller@gmail.com> | 2016-11-16 19:28:52 -0500 |
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committer | GitHub <noreply@github.com> | 2016-11-16 19:28:52 -0500 |
commit | 0135904f7d3e1c0e763adaefe267c736616e3d26 (patch) | |
tree | c27be7588f98eaea62e0bd0c0087f2b348da9738 /vendor/golang.org/x/image/vector/vector.go | |
parent | 0b296dd8c2aefefe89787be5cc627d44cf431150 (diff) | |
download | chat-0135904f7d3e1c0e763adaefe267c736616e3d26.tar.gz chat-0135904f7d3e1c0e763adaefe267c736616e3d26.tar.bz2 chat-0135904f7d3e1c0e763adaefe267c736616e3d26.zip |
Upgrading server dependancies (#4566)
Diffstat (limited to 'vendor/golang.org/x/image/vector/vector.go')
-rw-r--r-- | vendor/golang.org/x/image/vector/vector.go | 396 |
1 files changed, 320 insertions, 76 deletions
diff --git a/vendor/golang.org/x/image/vector/vector.go b/vendor/golang.org/x/image/vector/vector.go index 218e76489..852a4f8b7 100644 --- a/vendor/golang.org/x/image/vector/vector.go +++ b/vendor/golang.org/x/image/vector/vector.go @@ -2,6 +2,11 @@ // 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 +//go:generate asmfmt -w acc_amd64.s + +// asmfmt is https://github.com/klauspost/asmfmt + // Package vector provides a rasterizer for 2-D vector graphics. package vector // import "golang.org/x/image/vector" @@ -18,24 +23,33 @@ package vector // import "golang.org/x/image/vector" import ( "image" + "image/color" "image/draw" "math" - - "golang.org/x/image/math/f32" ) -func midPoint(p, q f32.Vec2) f32.Vec2 { - return f32.Vec2{ - (p[0] + q[0]) * 0.5, - (p[1] + q[1]) * 0.5, - } -} +// floatingPointMathThreshold is the width or height above which the rasterizer +// chooses to used floating point math instead of fixed point math. +// +// Both implementations of line segmentation rasterization (see raster_fixed.go +// and raster_floating.go) implement the same algorithm (in ideal, infinite +// precision math) but they perform differently in practice. The fixed point +// math version is roughtly 1.25x faster (on GOARCH=amd64) on the benchmarks, +// but at sufficiently large scales, the computations will overflow and hence +// show rendering artifacts. The floating point math version has more +// consistent quality over larger scales, but it is significantly slower. +// +// This constant determines when to use the faster implementation and when to +// use the better quality implementation. +// +// The rationale for this particular value is that TestRasterizePolygon in +// vector_test.go checks the rendering quality of polygon edges at various +// angles, inscribed in a circle of diameter 512. It may be that a higher value +// would still produce acceptable quality, but 512 seems to work. +const floatingPointMathThreshold = 512 -func lerp(t float32, p, q f32.Vec2) f32.Vec2 { - return f32.Vec2{ - p[0] + t*(q[0]-p[0]), - p[1] + t*(q[1]-p[1]), - } +func lerp(t, px, py, qx, qy float32) (x, y float32) { + return px + t*(qx-px), py + t*(qy-py) } func clamp(i, width int32) uint { @@ -51,18 +65,40 @@ func clamp(i, width int32) uint { // NewRasterizer returns a new Rasterizer whose rendered mask image is bounded // by the given width and height. func NewRasterizer(w, h int) *Rasterizer { - return &Rasterizer{ - area: make([]float32, w*h), - size: image.Point{w, h}, - } + z := &Rasterizer{} + z.Reset(w, h) + return z } // Raster is a 2-D vector graphics rasterizer. +// +// The zero value is usable, in that it is a Rasterizer whose rendered mask +// image has zero width and zero height. Call Reset to change its bounds. type Rasterizer struct { - area []float32 - size image.Point - first f32.Vec2 - pen f32.Vec2 + // bufXxx are buffers of float32 or uint32 values, holding either the + // individual or cumulative area values. + // + // We don't actually need both values at any given time, and to conserve + // memory, the integration of the individual to the cumulative could modify + // the buffer in place. In other words, we could use a single buffer, say + // of type []uint32, and add some math.Float32bits and math.Float32frombits + // calls to satisfy the compiler's type checking. As of Go 1.7, though, + // there is a performance penalty between: + // bufF32[i] += x + // and + // bufU32[i] = math.Float32bits(x + math.Float32frombits(bufU32[i])) + // + // See golang.org/issue/17220 for some discussion. + bufF32 []float32 + bufU32 []uint32 + + useFloatingPointMath bool + + size image.Point + firstX float32 + firstY float32 + penX float32 + penY float32 // DrawOp is the operator used for the Draw method. // @@ -77,18 +113,39 @@ type Rasterizer struct { // // This includes setting z.DrawOp to draw.Over. func (z *Rasterizer) Reset(w, h int) { - if n := w * h; n > cap(z.area) { - z.area = make([]float32, n) + z.size = image.Point{w, h} + z.firstX = 0 + z.firstY = 0 + z.penX = 0 + z.penY = 0 + z.DrawOp = draw.Over + + z.setUseFloatingPointMath(w > floatingPointMathThreshold || h > floatingPointMathThreshold) +} + +func (z *Rasterizer) setUseFloatingPointMath(b bool) { + z.useFloatingPointMath = b + + // Make z.bufF32 or z.bufU32 large enough to hold width * height samples. + if z.useFloatingPointMath { + if n := z.size.X * z.size.Y; n > cap(z.bufF32) { + z.bufF32 = make([]float32, n) + } else { + z.bufF32 = z.bufF32[:n] + for i := range z.bufF32 { + z.bufF32[i] = 0 + } + } } else { - z.area = z.area[:n] - for i := range z.area { - z.area[i] = 0 + if n := z.size.X * z.size.Y; n > cap(z.bufU32) { + z.bufU32 = make([]uint32, n) + } else { + z.bufU32 = z.bufU32[:n] + for i := range z.bufU32 { + z.bufU32[i] = 0 + } } } - z.size = image.Point{w, h} - z.first = f32.Vec2{} - z.pen = f32.Vec2{} - z.DrawOp = draw.Over } // Size returns the width and height passed to NewRasterizer or Reset. @@ -104,60 +161,66 @@ func (z *Rasterizer) Bounds() image.Rectangle { // Pen returns the location of the path-drawing pen: the last argument to the // most recent XxxTo call. -func (z *Rasterizer) Pen() f32.Vec2 { - return z.pen +func (z *Rasterizer) Pen() (x, y float32) { + return z.penX, z.penY } // ClosePath closes the current path. func (z *Rasterizer) ClosePath() { - z.LineTo(z.first) + z.LineTo(z.firstX, z.firstY) } -// MoveTo starts a new path and moves the pen to a. +// MoveTo starts a new path and moves the pen to (ax, ay). // // The coordinates are allowed to be out of the Rasterizer's bounds. -func (z *Rasterizer) MoveTo(a f32.Vec2) { - z.first = a - z.pen = a +func (z *Rasterizer) MoveTo(ax, ay float32) { + z.firstX = ax + z.firstY = ay + z.penX = ax + z.penY = ay } -// LineTo adds a line segment, from the pen to b, and moves the pen to b. +// LineTo adds a line segment, from the pen to (bx, by), and moves the pen to +// (bx, by). // // The coordinates are allowed to be out of the Rasterizer's bounds. -func (z *Rasterizer) LineTo(b f32.Vec2) { - // TODO: add a fixed point math implementation. - z.floatingLineTo(b) +func (z *Rasterizer) LineTo(bx, by float32) { + if z.useFloatingPointMath { + z.floatingLineTo(bx, by) + } else { + z.fixedLineTo(bx, by) + } } -// QuadTo adds a quadratic Bézier segment, from the pen via b to c, and moves -// the pen to c. +// QuadTo adds a quadratic Bézier segment, from the pen via (bx, by) to (cx, +// cy), and moves the pen to (cx, cy). // // The coordinates are allowed to be out of the Rasterizer's bounds. -func (z *Rasterizer) QuadTo(b, c f32.Vec2) { - a := z.pen - devsq := devSquared(a, b, c) +func (z *Rasterizer) QuadTo(bx, by, cx, cy float32) { + ax, ay := z.penX, z.penY + devsq := devSquared(ax, ay, bx, by, cx, cy) if devsq >= 0.333 { const tol = 3 n := 1 + int(math.Sqrt(math.Sqrt(tol*float64(devsq)))) t, nInv := float32(0), 1/float32(n) for i := 0; i < n-1; i++ { t += nInv - ab := lerp(t, a, b) - bc := lerp(t, b, c) - z.LineTo(lerp(t, ab, bc)) + abx, aby := lerp(t, ax, ay, bx, by) + bcx, bcy := lerp(t, bx, by, cx, cy) + z.LineTo(lerp(t, abx, aby, bcx, bcy)) } } - z.LineTo(c) + z.LineTo(cx, cy) } -// CubeTo adds a cubic Bézier segment, from the pen via b and c to d, and moves -// the pen to d. +// CubeTo adds a cubic Bézier segment, from the pen via (bx, by) and (cx, cy) +// to (dx, dy), and moves the pen to (dx, dy). // // The coordinates are allowed to be out of the Rasterizer's bounds. -func (z *Rasterizer) CubeTo(b, c, d f32.Vec2) { - a := z.pen - devsq := devSquared(a, b, d) - if devsqAlt := devSquared(a, c, d); devsq < devsqAlt { +func (z *Rasterizer) CubeTo(bx, by, cx, cy, dx, dy float32) { + ax, ay := z.penX, z.penY + devsq := devSquared(ax, ay, bx, by, dx, dy) + if devsqAlt := devSquared(ax, ay, cx, cy, dx, dy); devsq < devsqAlt { devsq = devsqAlt } if devsq >= 0.333 { @@ -166,19 +229,20 @@ func (z *Rasterizer) CubeTo(b, c, d f32.Vec2) { t, nInv := float32(0), 1/float32(n) for i := 0; i < n-1; i++ { t += nInv - ab := lerp(t, a, b) - bc := lerp(t, b, c) - cd := lerp(t, c, d) - abc := lerp(t, ab, bc) - bcd := lerp(t, bc, cd) - z.LineTo(lerp(t, abc, bcd)) + abx, aby := lerp(t, ax, ay, bx, by) + bcx, bcy := lerp(t, bx, by, cx, cy) + cdx, cdy := lerp(t, cx, cy, dx, dy) + abcx, abcy := lerp(t, abx, aby, bcx, bcy) + bcdx, bcdy := lerp(t, bcx, bcy, cdx, cdy) + z.LineTo(lerp(t, abcx, abcy, bcdx, bcdy)) } } - z.LineTo(d) + z.LineTo(dx, dy) } -// devSquared returns a measure of how curvy the sequnce a to b to c is. It -// determines how many line segments will approximate a Bézier curve segment. +// devSquared returns a measure of how curvy the sequence (ax, ay) to (bx, by) +// to (cx, cy) is. It determines how many line segments will approximate a +// Bézier curve segment. // // http://lists.nongnu.org/archive/html/freetype-devel/2016-08/msg00080.html // gives the rationale for this evenly spaced heuristic instead of a recursive @@ -190,9 +254,9 @@ func (z *Rasterizer) CubeTo(b, c, d f32.Vec2) { // Taking a circular arc as a simplifying assumption (ie a spherical cow), // where I get n, a recursive approach would get 2^⌈lg n⌉, which, if I haven't // made any horrible mistakes, is expected to be 33% more in the limit. -func devSquared(a, b, c f32.Vec2) float32 { - devx := a[0] - 2*b[0] + c[0] - devy := a[1] - 2*b[1] + c[1] +func devSquared(ax, ay, bx, by, cx, cy float32) float32 { + devx := ax - 2*bx + cx + devy := ay - 2*by + cy return devx*devx + devy*devy } @@ -202,27 +266,207 @@ func devSquared(a, b, c f32.Vec2) float32 { // The vector paths previously added via the XxxTo calls become the mask for // drawing src onto dst. func (z *Rasterizer) Draw(dst draw.Image, r image.Rectangle, src image.Image, sp image.Point) { + // TODO: adjust r and sp (and mp?) if src.Bounds() doesn't contain + // r.Add(sp.Sub(r.Min)). + if src, ok := src.(*image.Uniform); ok { - _, _, _, srcA := src.RGBA() + srcR, srcG, srcB, srcA := src.RGBA() switch dst := dst.(type) { case *image.Alpha: // Fast path for glyph rendering. - if srcA == 0xffff && z.DrawOp == draw.Src { - z.rasterizeDstAlphaSrcOpaqueOpSrc(dst, r) + if srcA == 0xffff { + if z.DrawOp == draw.Over { + z.rasterizeDstAlphaSrcOpaqueOpOver(dst, r) + } else { + z.rasterizeDstAlphaSrcOpaqueOpSrc(dst, r) + } return } + case *image.RGBA: + if z.DrawOp == draw.Over { + z.rasterizeDstRGBASrcUniformOpOver(dst, r, srcR, srcG, srcB, srcA) + } else { + z.rasterizeDstRGBASrcUniformOpSrc(dst, r, srcR, srcG, srcB, srcA) + } + return + } + } + + if z.DrawOp == draw.Over { + z.rasterizeOpOver(dst, r, src, sp) + } else { + z.rasterizeOpSrc(dst, r, src, sp) + } +} + +func (z *Rasterizer) accumulateMask() { + if z.useFloatingPointMath { + if n := z.size.X * z.size.Y; n > cap(z.bufU32) { + z.bufU32 = make([]uint32, n) + } else { + z.bufU32 = z.bufU32[:n] + } + if haveFloatingAccumulateSIMD { + floatingAccumulateMaskSIMD(z.bufU32, z.bufF32) + } else { + floatingAccumulateMask(z.bufU32, z.bufF32) + } + } else { + if haveFixedAccumulateSIMD { + fixedAccumulateMaskSIMD(z.bufU32) + } else { + fixedAccumulateMask(z.bufU32) + } + } +} + +func (z *Rasterizer) rasterizeDstAlphaSrcOpaqueOpOver(dst *image.Alpha, r image.Rectangle) { + // TODO: non-zero vs even-odd winding? + if r == dst.Bounds() && r == z.Bounds() { + // We bypass the z.accumulateMask step and convert straight from + // z.bufF32 or z.bufU32 to dst.Pix. + if z.useFloatingPointMath { + if haveFloatingAccumulateSIMD { + floatingAccumulateOpOverSIMD(dst.Pix, z.bufF32) + } else { + floatingAccumulateOpOver(dst.Pix, z.bufF32) + } + } else { + if haveFixedAccumulateSIMD { + fixedAccumulateOpOverSIMD(dst.Pix, z.bufU32) + } else { + fixedAccumulateOpOver(dst.Pix, z.bufU32) + } + } + return + } + + z.accumulateMask() + pix := dst.Pix[dst.PixOffset(r.Min.X, r.Min.Y):] + for y, y1 := 0, r.Max.Y-r.Min.Y; y < y1; y++ { + for x, x1 := 0, r.Max.X-r.Min.X; x < x1; x++ { + ma := z.bufU32[y*z.size.X+x] + i := y*dst.Stride + x + + // This formula is like rasterizeOpOver's, simplified for the + // concrete dst type and opaque src assumption. + a := 0xffff - ma + pix[i] = uint8((uint32(pix[i])*0x101*a/0xffff + ma) >> 8) } } - println("TODO: the general case") } func (z *Rasterizer) rasterizeDstAlphaSrcOpaqueOpSrc(dst *image.Alpha, r image.Rectangle) { - // TODO: add SIMD implementations. - // TODO: add a fixed point math implementation. // TODO: non-zero vs even-odd winding? if r == dst.Bounds() && r == z.Bounds() { - floatingAccumulate(dst.Pix, z.area) + // We bypass the z.accumulateMask step and convert straight from + // z.bufF32 or z.bufU32 to dst.Pix. + if z.useFloatingPointMath { + if haveFloatingAccumulateSIMD { + floatingAccumulateOpSrcSIMD(dst.Pix, z.bufF32) + } else { + floatingAccumulateOpSrc(dst.Pix, z.bufF32) + } + } else { + if haveFixedAccumulateSIMD { + fixedAccumulateOpSrcSIMD(dst.Pix, z.bufU32) + } else { + fixedAccumulateOpSrc(dst.Pix, z.bufU32) + } + } return } - println("TODO: the general case") + + z.accumulateMask() + pix := dst.Pix[dst.PixOffset(r.Min.X, r.Min.Y):] + for y, y1 := 0, r.Max.Y-r.Min.Y; y < y1; y++ { + for x, x1 := 0, r.Max.X-r.Min.X; x < x1; x++ { + ma := z.bufU32[y*z.size.X+x] + + // This formula is like rasterizeOpSrc's, simplified for the + // concrete dst type and opaque src assumption. + pix[y*dst.Stride+x] = uint8(ma >> 8) + } + } +} + +func (z *Rasterizer) rasterizeDstRGBASrcUniformOpOver(dst *image.RGBA, r image.Rectangle, sr, sg, sb, sa uint32) { + z.accumulateMask() + pix := dst.Pix[dst.PixOffset(r.Min.X, r.Min.Y):] + for y, y1 := 0, r.Max.Y-r.Min.Y; y < y1; y++ { + for x, x1 := 0, r.Max.X-r.Min.X; x < x1; x++ { + ma := z.bufU32[y*z.size.X+x] + + // This formula is like rasterizeOpOver's, simplified for the + // concrete dst type and uniform src assumption. + a := 0xffff - (sa * ma / 0xffff) + i := y*dst.Stride + 4*x + pix[i+0] = uint8(((uint32(pix[i+0])*0x101*a + sr*ma) / 0xffff) >> 8) + pix[i+1] = uint8(((uint32(pix[i+1])*0x101*a + sg*ma) / 0xffff) >> 8) + pix[i+2] = uint8(((uint32(pix[i+2])*0x101*a + sb*ma) / 0xffff) >> 8) + pix[i+3] = uint8(((uint32(pix[i+3])*0x101*a + sa*ma) / 0xffff) >> 8) + } + } +} + +func (z *Rasterizer) rasterizeDstRGBASrcUniformOpSrc(dst *image.RGBA, r image.Rectangle, sr, sg, sb, sa uint32) { + z.accumulateMask() + pix := dst.Pix[dst.PixOffset(r.Min.X, r.Min.Y):] + for y, y1 := 0, r.Max.Y-r.Min.Y; y < y1; y++ { + for x, x1 := 0, r.Max.X-r.Min.X; x < x1; x++ { + ma := z.bufU32[y*z.size.X+x] + + // This formula is like rasterizeOpSrc's, simplified for the + // concrete dst type and uniform src assumption. + i := y*dst.Stride + 4*x + pix[i+0] = uint8((sr * ma / 0xffff) >> 8) + pix[i+1] = uint8((sg * ma / 0xffff) >> 8) + pix[i+2] = uint8((sb * ma / 0xffff) >> 8) + pix[i+3] = uint8((sa * ma / 0xffff) >> 8) + } + } +} + +func (z *Rasterizer) rasterizeOpOver(dst draw.Image, r image.Rectangle, src image.Image, sp image.Point) { + z.accumulateMask() + out := color.RGBA64{} + outc := color.Color(&out) + for y, y1 := 0, r.Max.Y-r.Min.Y; y < y1; y++ { + for x, x1 := 0, r.Max.X-r.Min.X; x < x1; x++ { + sr, sg, sb, sa := src.At(sp.X+x, sp.Y+y).RGBA() + ma := z.bufU32[y*z.size.X+x] + + // This algorithm comes from the standard library's image/draw + // package. + dr, dg, db, da := dst.At(r.Min.X+x, r.Min.Y+y).RGBA() + a := 0xffff - (sa * ma / 0xffff) + out.R = uint16((dr*a + sr*ma) / 0xffff) + out.G = uint16((dg*a + sg*ma) / 0xffff) + out.B = uint16((db*a + sb*ma) / 0xffff) + out.A = uint16((da*a + sa*ma) / 0xffff) + + dst.Set(r.Min.X+x, r.Min.Y+y, outc) + } + } +} + +func (z *Rasterizer) rasterizeOpSrc(dst draw.Image, r image.Rectangle, src image.Image, sp image.Point) { + z.accumulateMask() + out := color.RGBA64{} + outc := color.Color(&out) + for y, y1 := 0, r.Max.Y-r.Min.Y; y < y1; y++ { + for x, x1 := 0, r.Max.X-r.Min.X; x < x1; x++ { + sr, sg, sb, sa := src.At(sp.X+x, sp.Y+y).RGBA() + ma := z.bufU32[y*z.size.X+x] + + // This algorithm comes from the standard library's image/draw + // package. + out.R = uint16(sr * ma / 0xffff) + out.G = uint16(sg * ma / 0xffff) + out.B = uint16(sb * ma / 0xffff) + out.A = uint16(sa * ma / 0xffff) + + dst.Set(r.Min.X+x, r.Min.Y+y, outc) + } + } } |