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path: root/src/pkg/exp/draw/draw.go
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Diffstat (limited to 'src/pkg/exp/draw/draw.go')
-rw-r--r--src/pkg/exp/draw/draw.go363
1 files changed, 0 insertions, 363 deletions
diff --git a/src/pkg/exp/draw/draw.go b/src/pkg/exp/draw/draw.go
deleted file mode 100644
index 1d0729d92..000000000
--- a/src/pkg/exp/draw/draw.go
+++ /dev/null
@@ -1,363 +0,0 @@
-// Copyright 2009 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.
-
-// Package draw provides basic graphics and drawing primitives,
-// in the style of the Plan 9 graphics library
-// (see http://plan9.bell-labs.com/magic/man2html/2/draw)
-// and the X Render extension.
-package draw
-
-import "image"
-
-// m is the maximum color value returned by image.Color.RGBA.
-const m = 1<<16 - 1
-
-// A Porter-Duff compositing operator.
-type Op int
-
-const (
- // Over specifies ``(src in mask) over dst''.
- Over Op = iota
- // Src specifies ``src in mask''.
- Src
-)
-
-var zeroColor image.Color = image.AlphaColor{0}
-
-// A draw.Image is an image.Image with a Set method to change a single pixel.
-type Image interface {
- image.Image
- Set(x, y int, c image.Color)
-}
-
-// Draw calls DrawMask with a nil mask and an Over op.
-func Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point) {
- DrawMask(dst, r, src, sp, nil, image.ZP, Over)
-}
-
-// DrawMask aligns r.Min in dst with sp in src and mp in mask and then replaces the rectangle r
-// in dst with the result of a Porter-Duff composition. A nil mask is treated as opaque.
-func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mask image.Image, mp image.Point, op Op) {
- sb := src.Bounds()
- dx, dy := sb.Max.X-sp.X, sb.Max.Y-sp.Y
- if mask != nil {
- mb := mask.Bounds()
- if dx > mb.Max.X-mp.X {
- dx = mb.Max.X - mp.X
- }
- if dy > mb.Max.Y-mp.Y {
- dy = mb.Max.Y - mp.Y
- }
- }
- if r.Dx() > dx {
- r.Max.X = r.Min.X + dx
- }
- if r.Dy() > dy {
- r.Max.Y = r.Min.Y + dy
- }
- r = r.Intersect(dst.Bounds())
- if r.Empty() {
- return
- }
-
- // Fast paths for special cases. If none of them apply, then we fall back to a general but slow implementation.
- if dst0, ok := dst.(*image.RGBA); ok {
- if op == Over {
- if mask == nil {
- if src0, ok := src.(*image.ColorImage); ok {
- drawFillOver(dst0, r, src0)
- return
- }
- if src0, ok := src.(*image.RGBA); ok {
- drawCopyOver(dst0, r, src0, sp)
- return
- }
- } else if mask0, ok := mask.(*image.Alpha); ok {
- if src0, ok := src.(*image.ColorImage); ok {
- drawGlyphOver(dst0, r, src0, mask0, mp)
- return
- }
- }
- } else {
- if mask == nil {
- if src0, ok := src.(*image.ColorImage); ok {
- drawFillSrc(dst0, r, src0)
- return
- }
- if src0, ok := src.(*image.RGBA); ok {
- drawCopySrc(dst0, r, src0, sp)
- return
- }
- }
- }
- drawRGBA(dst0, r, src, sp, mask, mp, op)
- return
- }
-
- x0, x1, dx := r.Min.X, r.Max.X, 1
- y0, y1, dy := r.Min.Y, r.Max.Y, 1
- if image.Image(dst) == src && r.Overlaps(r.Add(sp.Sub(r.Min))) {
- // Rectangles overlap: process backward?
- if sp.Y < r.Min.Y || sp.Y == r.Min.Y && sp.X < r.Min.X {
- x0, x1, dx = x1-1, x0-1, -1
- y0, y1, dy = y1-1, y0-1, -1
- }
- }
-
- var out *image.RGBA64Color
- sy := sp.Y + y0 - r.Min.Y
- my := mp.Y + y0 - r.Min.Y
- for y := y0; y != y1; y, sy, my = y+dy, sy+dy, my+dy {
- sx := sp.X + x0 - r.Min.X
- mx := mp.X + x0 - r.Min.X
- for x := x0; x != x1; x, sx, mx = x+dx, sx+dx, mx+dx {
- ma := uint32(m)
- if mask != nil {
- _, _, _, ma = mask.At(mx, my).RGBA()
- }
- switch {
- case ma == 0:
- if op == Over {
- // No-op.
- } else {
- dst.Set(x, y, zeroColor)
- }
- case ma == m && op == Src:
- dst.Set(x, y, src.At(sx, sy))
- default:
- sr, sg, sb, sa := src.At(sx, sy).RGBA()
- if out == nil {
- out = new(image.RGBA64Color)
- }
- if op == Over {
- dr, dg, db, da := dst.At(x, y).RGBA()
- a := m - (sa * ma / m)
- out.R = uint16((dr*a + sr*ma) / m)
- out.G = uint16((dg*a + sg*ma) / m)
- out.B = uint16((db*a + sb*ma) / m)
- out.A = uint16((da*a + sa*ma) / m)
- } else {
- out.R = uint16(sr * ma / m)
- out.G = uint16(sg * ma / m)
- out.B = uint16(sb * ma / m)
- out.A = uint16(sa * ma / m)
- }
- dst.Set(x, y, out)
- }
- }
- }
-}
-
-func drawFillOver(dst *image.RGBA, r image.Rectangle, src *image.ColorImage) {
- cr, cg, cb, ca := src.RGBA()
- // The 0x101 is here for the same reason as in drawRGBA.
- a := (m - ca) * 0x101
- x0, x1 := r.Min.X, r.Max.X
- y0, y1 := r.Min.Y, r.Max.Y
- for y := y0; y != y1; y++ {
- dbase := y * dst.Stride
- dpix := dst.Pix[dbase+x0 : dbase+x1]
- for i, rgba := range dpix {
- dr := (uint32(rgba.R)*a)/m + cr
- dg := (uint32(rgba.G)*a)/m + cg
- db := (uint32(rgba.B)*a)/m + cb
- da := (uint32(rgba.A)*a)/m + ca
- dpix[i] = image.RGBAColor{uint8(dr >> 8), uint8(dg >> 8), uint8(db >> 8), uint8(da >> 8)}
- }
- }
-}
-
-func drawCopyOver(dst *image.RGBA, r image.Rectangle, src *image.RGBA, sp image.Point) {
- dx0, dx1 := r.Min.X, r.Max.X
- dy0, dy1 := r.Min.Y, r.Max.Y
- nrows := dy1 - dy0
- sx0, sx1 := sp.X, sp.X+dx1-dx0
- d0 := dy0*dst.Stride + dx0
- d1 := dy0*dst.Stride + dx1
- s0 := sp.Y*src.Stride + sx0
- s1 := sp.Y*src.Stride + sx1
- var (
- ddelta, sdelta int
- i0, i1, idelta int
- )
- if r.Min.Y < sp.Y || r.Min.Y == sp.Y && r.Min.X <= sp.X {
- ddelta = dst.Stride
- sdelta = src.Stride
- i0, i1, idelta = 0, d1-d0, +1
- } else {
- // If the source start point is higher than the destination start point, or equal height but to the left,
- // then we compose the rows in right-to-left, bottom-up order instead of left-to-right, top-down.
- d0 += (nrows - 1) * dst.Stride
- d1 += (nrows - 1) * dst.Stride
- s0 += (nrows - 1) * src.Stride
- s1 += (nrows - 1) * src.Stride
- ddelta = -dst.Stride
- sdelta = -src.Stride
- i0, i1, idelta = d1-d0-1, -1, -1
- }
- for ; nrows > 0; nrows-- {
- dpix := dst.Pix[d0:d1]
- spix := src.Pix[s0:s1]
- for i := i0; i != i1; i += idelta {
- // For unknown reasons, even though both dpix[i] and spix[i] are
- // image.RGBAColors, on an x86 CPU it seems fastest to call RGBA
- // for the source but to do it manually for the destination.
- sr, sg, sb, sa := spix[i].RGBA()
- rgba := dpix[i]
- dr := uint32(rgba.R)
- dg := uint32(rgba.G)
- db := uint32(rgba.B)
- da := uint32(rgba.A)
- // The 0x101 is here for the same reason as in drawRGBA.
- a := (m - sa) * 0x101
- dr = (dr*a)/m + sr
- dg = (dg*a)/m + sg
- db = (db*a)/m + sb
- da = (da*a)/m + sa
- dpix[i] = image.RGBAColor{uint8(dr >> 8), uint8(dg >> 8), uint8(db >> 8), uint8(da >> 8)}
- }
- d0 += ddelta
- d1 += ddelta
- s0 += sdelta
- s1 += sdelta
- }
-}
-
-func drawGlyphOver(dst *image.RGBA, r image.Rectangle, src *image.ColorImage, mask *image.Alpha, mp image.Point) {
- x0, x1 := r.Min.X, r.Max.X
- y0, y1 := r.Min.Y, r.Max.Y
- cr, cg, cb, ca := src.RGBA()
- for y, my := y0, mp.Y; y != y1; y, my = y+1, my+1 {
- dbase := y * dst.Stride
- dpix := dst.Pix[dbase+x0 : dbase+x1]
- mbase := my * mask.Stride
- mpix := mask.Pix[mbase+mp.X:]
- for i, rgba := range dpix {
- ma := uint32(mpix[i].A)
- if ma == 0 {
- continue
- }
- ma |= ma << 8
- dr := uint32(rgba.R)
- dg := uint32(rgba.G)
- db := uint32(rgba.B)
- da := uint32(rgba.A)
- // The 0x101 is here for the same reason as in drawRGBA.
- a := (m - (ca * ma / m)) * 0x101
- dr = (dr*a + cr*ma) / m
- dg = (dg*a + cg*ma) / m
- db = (db*a + cb*ma) / m
- da = (da*a + ca*ma) / m
- dpix[i] = image.RGBAColor{uint8(dr >> 8), uint8(dg >> 8), uint8(db >> 8), uint8(da >> 8)}
- }
- }
-}
-
-func drawFillSrc(dst *image.RGBA, r image.Rectangle, src *image.ColorImage) {
- if r.Dy() < 1 {
- return
- }
- cr, cg, cb, ca := src.RGBA()
- color := image.RGBAColor{uint8(cr >> 8), uint8(cg >> 8), uint8(cb >> 8), uint8(ca >> 8)}
- // The built-in copy function is faster than a straightforward for loop to fill the destination with
- // the color, but copy requires a slice source. We therefore use a for loop to fill the first row, and
- // then use the first row as the slice source for the remaining rows.
- dx0, dx1 := r.Min.X, r.Max.X
- dy0, dy1 := r.Min.Y, r.Max.Y
- dbase := dy0 * dst.Stride
- i0, i1 := dbase+dx0, dbase+dx1
- firstRow := dst.Pix[i0:i1]
- for i := range firstRow {
- firstRow[i] = color
- }
- for y := dy0 + 1; y < dy1; y++ {
- i0 += dst.Stride
- i1 += dst.Stride
- copy(dst.Pix[i0:i1], firstRow)
- }
-}
-
-func drawCopySrc(dst *image.RGBA, r image.Rectangle, src *image.RGBA, sp image.Point) {
- dx0, dx1 := r.Min.X, r.Max.X
- dy0, dy1 := r.Min.Y, r.Max.Y
- nrows := dy1 - dy0
- sx0, sx1 := sp.X, sp.X+dx1-dx0
- d0 := dy0*dst.Stride + dx0
- d1 := dy0*dst.Stride + dx1
- s0 := sp.Y*src.Stride + sx0
- s1 := sp.Y*src.Stride + sx1
- var ddelta, sdelta int
- if r.Min.Y <= sp.Y {
- ddelta = dst.Stride
- sdelta = src.Stride
- } else {
- // If the source start point is higher than the destination start point, then we compose the rows
- // in bottom-up order instead of top-down. Unlike the drawCopyOver function, we don't have to
- // check the x co-ordinates because the built-in copy function can handle overlapping slices.
- d0 += (nrows - 1) * dst.Stride
- d1 += (nrows - 1) * dst.Stride
- s0 += (nrows - 1) * src.Stride
- s1 += (nrows - 1) * src.Stride
- ddelta = -dst.Stride
- sdelta = -src.Stride
- }
- for ; nrows > 0; nrows-- {
- copy(dst.Pix[d0:d1], src.Pix[s0:s1])
- d0 += ddelta
- d1 += ddelta
- s0 += sdelta
- s1 += sdelta
- }
-}
-
-func drawRGBA(dst *image.RGBA, r image.Rectangle, src image.Image, sp image.Point, mask image.Image, mp image.Point, op Op) {
- x0, x1, dx := r.Min.X, r.Max.X, 1
- y0, y1, dy := r.Min.Y, r.Max.Y, 1
- if image.Image(dst) == src && r.Overlaps(r.Add(sp.Sub(r.Min))) {
- if sp.Y < r.Min.Y || sp.Y == r.Min.Y && sp.X < r.Min.X {
- x0, x1, dx = x1-1, x0-1, -1
- y0, y1, dy = y1-1, y0-1, -1
- }
- }
-
- sy := sp.Y + y0 - r.Min.Y
- my := mp.Y + y0 - r.Min.Y
- for y := y0; y != y1; y, sy, my = y+dy, sy+dy, my+dy {
- sx := sp.X + x0 - r.Min.X
- mx := mp.X + x0 - r.Min.X
- dpix := dst.Pix[y*dst.Stride : (y+1)*dst.Stride]
- for x := x0; x != x1; x, sx, mx = x+dx, sx+dx, mx+dx {
- ma := uint32(m)
- if mask != nil {
- _, _, _, ma = mask.At(mx, my).RGBA()
- }
- sr, sg, sb, sa := src.At(sx, sy).RGBA()
- var dr, dg, db, da uint32
- if op == Over {
- rgba := dpix[x]
- dr = uint32(rgba.R)
- dg = uint32(rgba.G)
- db = uint32(rgba.B)
- da = uint32(rgba.A)
- // dr, dg, db and da are all 8-bit color at the moment, ranging in [0,255].
- // We work in 16-bit color, and so would normally do:
- // dr |= dr << 8
- // and similarly for dg, db and da, but instead we multiply a
- // (which is a 16-bit color, ranging in [0,65535]) by 0x101.
- // This yields the same result, but is fewer arithmetic operations.
- a := (m - (sa * ma / m)) * 0x101
- dr = (dr*a + sr*ma) / m
- dg = (dg*a + sg*ma) / m
- db = (db*a + sb*ma) / m
- da = (da*a + sa*ma) / m
- } else {
- dr = sr * ma / m
- dg = sg * ma / m
- db = sb * ma / m
- da = sa * ma / m
- }
- dpix[x] = image.RGBAColor{uint8(dr >> 8), uint8(dg >> 8), uint8(db >> 8), uint8(da >> 8)}
- }
- }
-}
generated by cgit v1.2.3 (git 2.39.1) at 2025-05-02 19:11:51 +0000