From 4e2035bdc224f139ab48fba941484e5a22c682cb Mon Sep 17 00:00:00 2001 From: Nigel Tao Date: Thu, 4 Feb 2010 21:21:32 +1100 Subject: [PATCH] In draw.Draw, separate the source-point and mask-point. This lets you draw text (i.e. with mask = a font image) with sources that aren't uniform colors. R=r, rsc CC=golang-dev https://golang.org/cl/193067 --- src/pkg/exp/4s/xs.go | 52 ++++++++++++++--------------- src/pkg/exp/draw/draw.go | 70 +++++++++++++++++++++++----------------- 2 files changed, 66 insertions(+), 56 deletions(-) diff --git a/src/pkg/exp/4s/xs.go b/src/pkg/exp/4s/xs.go index 94a6f8597b1..e1d28c88501 100644 --- a/src/pkg/exp/4s/xs.go +++ b/src/pkg/exp/4s/xs.go @@ -226,8 +226,8 @@ func collider(pt, pmax draw.Point) bool { } func setpiece(p *Piece) { - draw.Draw(bb, bbr, draw.White, nil, draw.ZP) - draw.Draw(bbmask, bbr, draw.Transparent, nil, draw.ZP) + draw.Draw(bb, bbr, draw.White, draw.ZP) + draw.Draw(bbmask, bbr, draw.Transparent, draw.ZP) br = draw.Rect(0, 0, 0, 0) br2 = br piece = p @@ -243,13 +243,13 @@ func setpiece(p *Piece) { r.Max.X = r.Min.X + pcsz r.Max.Y = r.Min.Y + pcsz if i == 0 { - draw.Draw(bb, r, draw.Black, nil, draw.ZP) - draw.Draw(bb, r.Inset(1), txpix[piece.tx], nil, draw.ZP) - draw.Draw(bbmask, r, draw.Opaque, nil, draw.ZP) + draw.Draw(bb, r, draw.Black, draw.ZP) + draw.Draw(bb, r.Inset(1), txpix[piece.tx], draw.ZP) + draw.Draw(bbmask, r, draw.Opaque, draw.ZP) op = r.Min } else { - draw.Draw(bb, r, bb, nil, op) - draw.Draw(bbmask, r, bbmask, nil, op) + draw.Draw(bb, r, bb, op) + draw.Draw(bbmask, r, bbmask, op) } if br.Max.X < r.Max.X { br.Max.X = r.Max.X @@ -263,17 +263,17 @@ func setpiece(p *Piece) { br2.Max = br.Max.Add(delta) r = br.Add(bb2r.Min) r2 := br2.Add(bb2r.Min) - draw.Draw(bb2, r2, draw.White, nil, draw.ZP) - draw.Draw(bb2, r.Add(delta), bb, nil, bbr.Min) - draw.Draw(bb2mask, r2, draw.Transparent, nil, draw.ZP) - draw.Draw(bb2mask, r, draw.Opaque, bbmask, bbr.Min) - draw.Draw(bb2mask, r.Add(delta), draw.Opaque, bbmask, bbr.Min) + draw.Draw(bb2, r2, draw.White, draw.ZP) + draw.Draw(bb2, r.Add(delta), bb, bbr.Min) + draw.Draw(bb2mask, r2, draw.Transparent, draw.ZP) + draw.DrawMask(bb2mask, r, draw.Opaque, bbr.Min, bbmask, draw.ZP, draw.SoverD) + draw.DrawMask(bb2mask, r.Add(delta), draw.Opaque, bbr.Min, bbmask, draw.ZP, draw.SoverD) } func drawpiece() { - draw.Draw(screen, br.Add(pos), bb, bbmask, bbr.Min) + draw.DrawMask(screen, br.Add(pos), bb, bbr.Min, bbmask, draw.ZP, draw.SoverD) if suspended { - draw.Draw(screen, br.Add(pos), draw.White, whitemask, draw.ZP) + draw.DrawMask(screen, br.Add(pos), draw.White, draw.ZP, whitemask, draw.ZP, draw.SoverD) } } @@ -282,7 +282,7 @@ func undrawpiece() { if collider(pos, br.Max) { mask = bbmask } - draw.Draw(screen, br.Add(pos), draw.White, mask, bbr.Min) + draw.DrawMask(screen, br.Add(pos), draw.White, bbr.Min, mask, bbr.Min, draw.SoverD) } func rest() { @@ -323,7 +323,7 @@ func canfit(p *Piece) bool { func score(p int) { points += p // snprint(buf, sizeof(buf), "%.6ld", points); - // draw.Draw(screen, draw.Rpt(pscore, pscore.Add(scoresz)), draw.White, nil, draw.ZP); + // draw.Draw(screen, draw.Rpt(pscore, pscore.Add(scoresz)), draw.White, draw.ZP); // string(screen, pscore, draw.Black, draw.ZP, font, buf); } @@ -332,14 +332,14 @@ func drawsq(b draw.Image, p draw.Point, ptx int) { r.Min = p r.Max.X = r.Min.X + pcsz r.Max.Y = r.Min.Y + pcsz - draw.Draw(b, r, draw.Black, nil, draw.ZP) - draw.Draw(b, r.Inset(1), txpix[ptx], nil, draw.ZP) + draw.Draw(b, r, draw.Black, draw.ZP) + draw.Draw(b, r.Inset(1), txpix[ptx], draw.ZP) } func drawboard() { draw.Border(screen, rboard.Inset(-2), 2, draw.Black, draw.ZP) draw.Draw(screen, draw.Rect(rboard.Min.X, rboard.Min.Y-2, rboard.Max.X, rboard.Min.Y), - draw.White, nil, draw.ZP) + draw.White, draw.ZP) for i := 0; i < NY; i++ { for j := 0; j < NX; j++ { if board[i][j] != 0 { @@ -349,7 +349,7 @@ func drawboard() { } score(0) if suspended { - draw.Draw(screen, screenr, draw.White, whitemask, draw.ZP) + draw.DrawMask(screen, screenr, draw.White, draw.ZP, whitemask, draw.ZP, draw.SoverD) } } @@ -375,7 +375,7 @@ func movepiece() bool { if collider(pos, br2.Max) { mask = bb2mask } - draw.Draw(screen, br2.Add(pos), bb2, mask, bb2r.Min) + draw.DrawMask(screen, br2.Add(pos), bb2, bb2r.Min, mask, bb2r.Min, draw.SoverD) pos.Y += DY display.FlushImage() return true @@ -444,7 +444,7 @@ func horiz() bool { for j := 0; j < h; j++ { r.Min.Y = rboard.Min.Y + lev[j]*pcsz r.Max.Y = r.Min.Y + pcsz - draw.Draw(screen, r, draw.White, whitemask, draw.ZP) + draw.DrawMask(screen, r, draw.White, draw.ZP, whitemask, draw.ZP, draw.SoverD) display.FlushImage() } PlaySound(whoosh) @@ -457,7 +457,7 @@ func horiz() bool { for j := 0; j < h; j++ { r.Min.Y = rboard.Min.Y + lev[j]*pcsz r.Max.Y = r.Min.Y + pcsz - draw.Draw(screen, r, draw.White, whitemask, draw.ZP) + draw.DrawMask(screen, r, draw.White, draw.ZP, whitemask, draw.ZP, draw.SoverD) } display.FlushImage() } @@ -467,9 +467,9 @@ func horiz() bool { score(250 + 10*i*i) r.Min.Y = rboard.Min.Y r.Max.Y = rboard.Min.Y + lev[j]*pcsz - draw.Draw(screen, r.Add(draw.Pt(0, pcsz)), screen, nil, r.Min) + draw.Draw(screen, r.Add(draw.Pt(0, pcsz)), screen, r.Min) r.Max.Y = rboard.Min.Y + pcsz - draw.Draw(screen, r, draw.White, nil, draw.ZP) + draw.Draw(screen, r, draw.White, draw.ZP) for k := lev[j] - 1; k >= 0; k-- { board[k+1] = board[k] } @@ -703,7 +703,7 @@ func redraw(new bool) { bb2r = draw.Rect(0, 0, N*pcsz, N*pcsz+DY) bb2 = image.NewRGBA(bb2r.Dx(), bb2r.Dy()) bb2mask = image.NewRGBA(bb2r.Dx(), bb2r.Dy()) // actually just a bitmap - draw.Draw(screen, screenr, draw.White, nil, draw.ZP) + draw.Draw(screen, screenr, draw.White, draw.ZP) drawboard() setpiece(piece) if piece != nil { diff --git a/src/pkg/exp/draw/draw.go b/src/pkg/exp/draw/draw.go index 3455eacb9e1..d7722acfc75 100644 --- a/src/pkg/exp/draw/draw.go +++ b/src/pkg/exp/draw/draw.go @@ -12,32 +12,37 @@ package draw import "image" +// A Porter-Duff compositing operator. +type Op int + +const SoverD Op = 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 aligns r.Min in dst with pt in src and mask -// and then replaces the rectangle r in dst with the -// result of the Porter-Duff compositing operation -// ``(src in mask) over dst.'' If mask is nil, the operation -// simplifies to ``src over dst.'' -// The implementation is simple and slow. -func Draw(dst Image, r Rectangle, src, mask image.Image, pt Point) { - // Plenty of room for optimizations here. +// Draw calls DrawMask with a nil mask and an SoverD op. +func Draw(dst Image, r Rectangle, src image.Image, sp Point) { + DrawMask(dst, r, src, sp, nil, ZP, SoverD) +} - dx, dy := src.Width(), src.Height() +// 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. For the SoverD operator, the result +// is ``(src in mask) over dst''. If mask is nil, this simplifies to ``src over dst''. +// The implementation is simple and slow. +// TODO(nigeltao): Optimize this. +func DrawMask(dst Image, r Rectangle, src image.Image, sp Point, mask image.Image, mp Point, op Op) { + dx, dy := src.Width()-sp.X, src.Height()-sp.Y if mask != nil { - if dx > mask.Width() { - dx = mask.Width() + if dx > mask.Width()-mp.X { + dx = mask.Width() - mp.X } - if dy > mask.Height() { - dy = mask.Height() + if dy > mask.Height()-mp.Y { + dy = mask.Height() - mp.Y } } - dx -= pt.X - dy -= pt.Y if r.Dx() > dx { r.Max.X = r.Min.X + dx } @@ -45,26 +50,31 @@ func Draw(dst Image, r Rectangle, src, mask image.Image, pt Point) { r.Max.Y = r.Min.Y + dy } + // TODO(nigeltao): Clip r to dst's bounding box, and handle the case when sp or mp has negative X or Y. + 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(pt.Sub(r.Min))) { + if image.Image(dst) == src && r.Overlaps(r.Add(sp.Sub(r.Min))) { // Rectangles overlap: process backward? - if pt.Y < r.Min.Y || pt.Y == r.Min.Y && pt.X < r.Min.X { + 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 - for y := y0; y != y1; y += dy { - for x := x0; x != x1; x += dx { - sx := pt.X + x - r.Min.X - sy := pt.Y + y - r.Min.Y + 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 { + // TODO(nigeltao): Check that op == SoverD. if mask == nil { dst.Set(x, y, src.At(sx, sy)) continue } - _, _, _, ma := mask.At(sx, sy).RGBA() + _, _, _, ma := mask.At(mx, my).RGBA() switch ma { case 0: continue @@ -109,17 +119,17 @@ func Border(dst Image, r Rectangle, w int, src image.Image, sp Point) { i := w if i > 0 { // inside r - Draw(dst, Rect(r.Min.X, r.Min.Y, r.Max.X, r.Min.Y+i), src, nil, sp) // top - Draw(dst, Rect(r.Min.X, r.Min.Y+i, r.Min.X+i, r.Max.Y-i), src, nil, sp.Add(Pt(0, i))) // left - Draw(dst, Rect(r.Max.X-i, r.Min.Y+i, r.Max.X, r.Max.Y-i), src, nil, sp.Add(Pt(r.Dx()-i, i))) // right - Draw(dst, Rect(r.Min.X, r.Max.Y-i, r.Max.X, r.Max.Y), src, nil, sp.Add(Pt(0, r.Dy()-i))) // bottom + Draw(dst, Rect(r.Min.X, r.Min.Y, r.Max.X, r.Min.Y+i), src, sp) // top + Draw(dst, Rect(r.Min.X, r.Min.Y+i, r.Min.X+i, r.Max.Y-i), src, sp.Add(Pt(0, i))) // left + Draw(dst, Rect(r.Max.X-i, r.Min.Y+i, r.Max.X, r.Max.Y-i), src, sp.Add(Pt(r.Dx()-i, i))) // right + Draw(dst, Rect(r.Min.X, r.Max.Y-i, r.Max.X, r.Max.Y), src, sp.Add(Pt(0, r.Dy()-i))) // bottom return } // outside r; i = -i - Draw(dst, Rect(r.Min.X-i, r.Min.Y-i, r.Max.X+i, r.Min.Y), src, nil, sp.Add(Pt(-i, -i))) // top - Draw(dst, Rect(r.Min.X-i, r.Min.Y, r.Min.X, r.Max.Y), src, nil, sp.Add(Pt(-i, 0))) // left - Draw(dst, Rect(r.Max.X, r.Min.Y, r.Max.X+i, r.Max.Y), src, nil, sp.Add(Pt(r.Dx(), 0))) // right - Draw(dst, Rect(r.Min.X-i, r.Max.Y, r.Max.X+i, r.Max.Y+i), src, nil, sp.Add(Pt(-i, 0))) // bottom + Draw(dst, Rect(r.Min.X-i, r.Min.Y-i, r.Max.X+i, r.Min.Y), src, sp.Add(Pt(-i, -i))) // top + Draw(dst, Rect(r.Min.X-i, r.Min.Y, r.Min.X, r.Max.Y), src, sp.Add(Pt(-i, 0))) // left + Draw(dst, Rect(r.Max.X, r.Min.Y, r.Max.X+i, r.Max.Y), src, sp.Add(Pt(r.Dx(), 0))) // right + Draw(dst, Rect(r.Min.X-i, r.Max.Y, r.Max.X+i, r.Max.Y+i), src, sp.Add(Pt(-i, 0))) // bottom }