diff options
Diffstat (limited to 'Godeps/_workspace/src/code.google.com/p/freetype-go/freetype/raster/paint.go')
-rw-r--r-- | Godeps/_workspace/src/code.google.com/p/freetype-go/freetype/raster/paint.go | 292 |
1 files changed, 0 insertions, 292 deletions
diff --git a/Godeps/_workspace/src/code.google.com/p/freetype-go/freetype/raster/paint.go b/Godeps/_workspace/src/code.google.com/p/freetype-go/freetype/raster/paint.go deleted file mode 100644 index 13cccc192..000000000 --- a/Godeps/_workspace/src/code.google.com/p/freetype-go/freetype/raster/paint.go +++ /dev/null @@ -1,292 +0,0 @@ -// Copyright 2010 The Freetype-Go Authors. All rights reserved. -// Use of this source code is governed by your choice of either the -// FreeType License or the GNU General Public License version 2 (or -// any later version), both of which can be found in the LICENSE file. - -package raster - -import ( - "image" - "image/color" - "image/draw" - "math" -) - -// A Span is a horizontal segment of pixels with constant alpha. X0 is an -// inclusive bound and X1 is exclusive, the same as for slices. A fully -// opaque Span has A == 1<<32 - 1. -type Span struct { - Y, X0, X1 int - A uint32 -} - -// A Painter knows how to paint a batch of Spans. Rasterization may involve -// Painting multiple batches, and done will be true for the final batch. -// The Spans' Y values are monotonically increasing during a rasterization. -// Paint may use all of ss as scratch space during the call. -type Painter interface { - Paint(ss []Span, done bool) -} - -// The PainterFunc type adapts an ordinary function to the Painter interface. -type PainterFunc func(ss []Span, done bool) - -// Paint just delegates the call to f. -func (f PainterFunc) Paint(ss []Span, done bool) { f(ss, done) } - -// An AlphaOverPainter is a Painter that paints Spans onto an image.Alpha -// using the Over Porter-Duff composition operator. -type AlphaOverPainter struct { - Image *image.Alpha -} - -// Paint satisfies the Painter interface by painting ss onto an image.Alpha. -func (r AlphaOverPainter) Paint(ss []Span, done bool) { - b := r.Image.Bounds() - for _, s := range ss { - if s.Y < b.Min.Y { - continue - } - if s.Y >= b.Max.Y { - return - } - if s.X0 < b.Min.X { - s.X0 = b.Min.X - } - if s.X1 > b.Max.X { - s.X1 = b.Max.X - } - if s.X0 >= s.X1 { - continue - } - base := (s.Y-r.Image.Rect.Min.Y)*r.Image.Stride - r.Image.Rect.Min.X - p := r.Image.Pix[base+s.X0 : base+s.X1] - a := int(s.A >> 24) - for i, c := range p { - v := int(c) - p[i] = uint8((v*255 + (255-v)*a) / 255) - } - } -} - -// NewAlphaOverPainter creates a new AlphaOverPainter for the given image. -func NewAlphaOverPainter(m *image.Alpha) AlphaOverPainter { - return AlphaOverPainter{m} -} - -// An AlphaSrcPainter is a Painter that paints Spans onto an image.Alpha -// using the Src Porter-Duff composition operator. -type AlphaSrcPainter struct { - Image *image.Alpha -} - -// Paint satisfies the Painter interface by painting ss onto an image.Alpha. -func (r AlphaSrcPainter) Paint(ss []Span, done bool) { - b := r.Image.Bounds() - for _, s := range ss { - if s.Y < b.Min.Y { - continue - } - if s.Y >= b.Max.Y { - return - } - if s.X0 < b.Min.X { - s.X0 = b.Min.X - } - if s.X1 > b.Max.X { - s.X1 = b.Max.X - } - if s.X0 >= s.X1 { - continue - } - base := (s.Y-r.Image.Rect.Min.Y)*r.Image.Stride - r.Image.Rect.Min.X - p := r.Image.Pix[base+s.X0 : base+s.X1] - color := uint8(s.A >> 24) - for i := range p { - p[i] = color - } - } -} - -// NewAlphaSrcPainter creates a new AlphaSrcPainter for the given image. -func NewAlphaSrcPainter(m *image.Alpha) AlphaSrcPainter { - return AlphaSrcPainter{m} -} - -type RGBAPainter struct { - // The image to compose onto. - Image *image.RGBA - // The Porter-Duff composition operator. - Op draw.Op - // The 16-bit color to paint the spans. - cr, cg, cb, ca uint32 -} - -// Paint satisfies the Painter interface by painting ss onto an image.RGBA. -func (r *RGBAPainter) Paint(ss []Span, done bool) { - b := r.Image.Bounds() - for _, s := range ss { - if s.Y < b.Min.Y { - continue - } - if s.Y >= b.Max.Y { - return - } - if s.X0 < b.Min.X { - s.X0 = b.Min.X - } - if s.X1 > b.Max.X { - s.X1 = b.Max.X - } - if s.X0 >= s.X1 { - continue - } - // This code is similar to drawGlyphOver in $GOROOT/src/pkg/image/draw/draw.go. - ma := s.A >> 16 - const m = 1<<16 - 1 - i0 := (s.Y-r.Image.Rect.Min.Y)*r.Image.Stride + (s.X0-r.Image.Rect.Min.X)*4 - i1 := i0 + (s.X1-s.X0)*4 - if r.Op == draw.Over { - for i := i0; i < i1; i += 4 { - dr := uint32(r.Image.Pix[i+0]) - dg := uint32(r.Image.Pix[i+1]) - db := uint32(r.Image.Pix[i+2]) - da := uint32(r.Image.Pix[i+3]) - a := (m - (r.ca * ma / m)) * 0x101 - r.Image.Pix[i+0] = uint8((dr*a + r.cr*ma) / m >> 8) - r.Image.Pix[i+1] = uint8((dg*a + r.cg*ma) / m >> 8) - r.Image.Pix[i+2] = uint8((db*a + r.cb*ma) / m >> 8) - r.Image.Pix[i+3] = uint8((da*a + r.ca*ma) / m >> 8) - } - } else { - for i := i0; i < i1; i += 4 { - r.Image.Pix[i+0] = uint8(r.cr * ma / m >> 8) - r.Image.Pix[i+1] = uint8(r.cg * ma / m >> 8) - r.Image.Pix[i+2] = uint8(r.cb * ma / m >> 8) - r.Image.Pix[i+3] = uint8(r.ca * ma / m >> 8) - } - } - } -} - -// SetColor sets the color to paint the spans. -func (r *RGBAPainter) SetColor(c color.Color) { - r.cr, r.cg, r.cb, r.ca = c.RGBA() -} - -// NewRGBAPainter creates a new RGBAPainter for the given image. -func NewRGBAPainter(m *image.RGBA) *RGBAPainter { - return &RGBAPainter{Image: m} -} - -// A MonochromePainter wraps another Painter, quantizing each Span's alpha to -// be either fully opaque or fully transparent. -type MonochromePainter struct { - Painter Painter - y, x0, x1 int -} - -// Paint delegates to the wrapped Painter after quantizing each Span's alpha -// value and merging adjacent fully opaque Spans. -func (m *MonochromePainter) Paint(ss []Span, done bool) { - // We compact the ss slice, discarding any Spans whose alpha quantizes to zero. - j := 0 - for _, s := range ss { - if s.A >= 1<<31 { - if m.y == s.Y && m.x1 == s.X0 { - m.x1 = s.X1 - } else { - ss[j] = Span{m.y, m.x0, m.x1, 1<<32 - 1} - j++ - m.y, m.x0, m.x1 = s.Y, s.X0, s.X1 - } - } - } - if done { - // Flush the accumulated Span. - finalSpan := Span{m.y, m.x0, m.x1, 1<<32 - 1} - if j < len(ss) { - ss[j] = finalSpan - j++ - m.Painter.Paint(ss[:j], true) - } else if j == len(ss) { - m.Painter.Paint(ss, false) - if cap(ss) > 0 { - ss = ss[:1] - } else { - ss = make([]Span, 1) - } - ss[0] = finalSpan - m.Painter.Paint(ss, true) - } else { - panic("unreachable") - } - // Reset the accumulator, so that this Painter can be re-used. - m.y, m.x0, m.x1 = 0, 0, 0 - } else { - m.Painter.Paint(ss[:j], false) - } -} - -// NewMonochromePainter creates a new MonochromePainter that wraps the given -// Painter. -func NewMonochromePainter(p Painter) *MonochromePainter { - return &MonochromePainter{Painter: p} -} - -// A GammaCorrectionPainter wraps another Painter, performing gamma-correction -// on each Span's alpha value. -type GammaCorrectionPainter struct { - // The wrapped Painter. - Painter Painter - // Precomputed alpha values for linear interpolation, with fully opaque == 1<<16-1. - a [256]uint16 - // Whether gamma correction is a no-op. - gammaIsOne bool -} - -// Paint delegates to the wrapped Painter after performing gamma-correction -// on each Span. -func (g *GammaCorrectionPainter) Paint(ss []Span, done bool) { - if !g.gammaIsOne { - const ( - M = 0x1010101 // 255*M == 1<<32-1 - N = 0x8080 // N = M>>9, and N < 1<<16-1 - ) - for i, s := range ss { - if s.A == 0 || s.A == 1<<32-1 { - continue - } - p, q := s.A/M, (s.A%M)>>9 - // The resultant alpha is a linear interpolation of g.a[p] and g.a[p+1]. - a := uint32(g.a[p])*(N-q) + uint32(g.a[p+1])*q - a = (a + N/2) / N - // Convert the alpha from 16-bit (which is g.a's range) to 32-bit. - a |= a << 16 - ss[i].A = a - } - } - g.Painter.Paint(ss, done) -} - -// SetGamma sets the gamma value. -func (g *GammaCorrectionPainter) SetGamma(gamma float64) { - if gamma == 1.0 { - g.gammaIsOne = true - return - } - g.gammaIsOne = false - for i := 0; i < 256; i++ { - a := float64(i) / 0xff - a = math.Pow(a, gamma) - g.a[i] = uint16(0xffff * a) - } -} - -// NewGammaCorrectionPainter creates a new GammaCorrectionPainter that wraps -// the given Painter. -func NewGammaCorrectionPainter(p Painter, gamma float64) *GammaCorrectionPainter { - g := &GammaCorrectionPainter{Painter: p} - g.SetGamma(gamma) - return g -} |