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Commit ae5a972d authored by Nigel Tao's avatar Nigel Tao
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exp/draw: fix clipping bug where sp/mp were not shifted when r.Min was. 

image: add Rectangle.ContainsRectangle method.

R=r, rsc
CC=golang-dev
https://golang.org/cl/4517130
parent f628f741
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Showing with 231 additions and 23 deletions
src/pkg/exp/draw/clip_test.go 0 → 100644
View file @ ae5a972d
// Copyright 2011 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
import (
"image"
"testing"
)
type clipTest struct {
desc string
r, dr, sr, mr image.Rectangle
sp, mp image.Point
nilMask bool
r0 image.Rectangle
sp0, mp0 image.Point
}
var clipTests = []clipTest{
// The following tests all have a nil mask.
{
"basic",
image.Rect(0, 0, 100, 100),
image.Rect(0, 0, 100, 100),
image.Rect(0, 0, 100, 100),
image.ZR,
image.ZP,
image.ZP,
true,
image.Rect(0, 0, 100, 100),
image.ZP,
image.ZP,
},
{
"clip dr",
image.Rect(0, 0, 100, 100),
image.Rect(40, 40, 60, 60),
image.Rect(0, 0, 100, 100),
image.ZR,
image.ZP,
image.ZP,
true,
image.Rect(40, 40, 60, 60),
image.Pt(40, 40),
image.ZP,
},
{
"clip sr",
image.Rect(0, 0, 100, 100),
image.Rect(0, 0, 100, 100),
image.Rect(20, 20, 80, 80),
image.ZR,
image.ZP,
image.ZP,
true,
image.Rect(20, 20, 80, 80),
image.Pt(20, 20),
image.ZP,
},
{
"clip dr and sr",
image.Rect(0, 0, 100, 100),
image.Rect(0, 0, 50, 100),
image.Rect(20, 20, 80, 80),
image.ZR,
image.ZP,
image.ZP,
true,
image.Rect(20, 20, 50, 80),
image.Pt(20, 20),
image.ZP,
},
{
"clip dr and sr, sp outside sr (top-left)",
image.Rect(0, 0, 100, 100),
image.Rect(0, 0, 50, 100),
image.Rect(20, 20, 80, 80),
image.ZR,
image.Pt(15, 8),
image.ZP,
true,
image.Rect(5, 12, 50, 72),
image.Pt(20, 20),
image.ZP,
},
{
"clip dr and sr, sp outside sr (middle-left)",
image.Rect(0, 0, 100, 100),
image.Rect(0, 0, 50, 100),
image.Rect(20, 20, 80, 80),
image.ZR,
image.Pt(15, 66),
image.ZP,
true,
image.Rect(5, 0, 50, 14),
image.Pt(20, 66),
image.ZP,
},
{
"clip dr and sr, sp outside sr (bottom-left)",
image.Rect(0, 0, 100, 100),
image.Rect(0, 0, 50, 100),
image.Rect(20, 20, 80, 80),
image.ZR,
image.Pt(15, 91),
image.ZP,
true,
image.ZR,
image.Pt(15, 91),
image.ZP,
},
{
"clip dr and sr, sp inside sr",
image.Rect(0, 0, 100, 100),
image.Rect(0, 0, 50, 100),
image.Rect(20, 20, 80, 80),
image.ZR,
image.Pt(44, 33),
image.ZP,
true,
image.Rect(0, 0, 36, 47),
image.Pt(44, 33),
image.ZP,
},
// The following tests all have a non-nil mask.
{
"basic mask",
image.Rect(0, 0, 80, 80),
image.Rect(20, 0, 100, 80),
image.Rect(0, 0, 50, 49),
image.Rect(0, 0, 46, 47),
image.ZP,
image.ZP,
false,
image.Rect(20, 0, 46, 47),
image.Pt(20, 0),
image.Pt(20, 0),
},
// TODO(nigeltao): write more tests.
}
func TestClip(t *testing.T) {
dst0 := image.NewRGBA(100, 100)
src0 := image.NewRGBA(100, 100)
mask0 := image.NewRGBA(100, 100)
for _, c := range clipTests {
dst := dst0.SubImage(c.dr).(*image.RGBA)
src := src0.SubImage(c.sr).(*image.RGBA)
var mask image.Image
if !c.nilMask {
mask = mask0.SubImage(c.mr)
}
r, sp, mp := c.r, c.sp, c.mp
clip(dst, &r, src, &sp, mask, &mp)
// Check that the actual results equal the expected results.
if !c.r0.Eq(r) {
t.Errorf("%s: clip rectangle want %v got %v", c.desc, c.r0, r)
continue
}
if !c.sp0.Eq(sp) {
t.Errorf("%s: sp want %v got %v", c.desc, c.sp0, sp)
continue
}
if !c.nilMask {
if !c.mp0.Eq(mp) {
t.Errorf("%s: mp want %v got %v", c.desc, c.mp0, mp)
continue
}
}
// Check that the clipped rectangle is contained by the dst / src / mask
// rectangles, in their respective co-ordinate spaces.
if !c.dr.ContainsRectangle(r) {
t.Errorf("%s: c.dr %v does not contain r %v", c.desc, c.dr, r)
}
// sr is r translated into src's co-ordinate space.
sr := r.Add(c.sp.Sub(c.dr.Min))
if !c.sr.ContainsRectangle(sr) {
t.Errorf("%s: c.sr %v does not contain sr %v", c.desc, c.sr, sr)
}
if !c.nilMask {
// mr is r translated into mask's co-ordinate space.
mr := r.Add(c.mp.Sub(c.dr.Min))
if !c.mr.ContainsRectangle(mr) {
t.Errorf("%s: c.mr %v does not contain mr %v", c.desc, c.mr, mr)
}
}
}
}
src/pkg/exp/draw/draw.go
View file @ ae5a972d
......@@ -39,27 +39,31 @@ 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
// clip clips r against each image's bounds (after translating into the
// destination image's co-ordinate space) and shifts the points sp and mp by
// the same amount as the change in r.Min.
func clip(dst Image, r *image.Rectangle, src image.Image, sp *image.Point, mask image.Image, mp *image.Point) {
orig := r.Min
*r = r.Intersect(dst.Bounds())
*r = r.Intersect(src.Bounds().Add(orig.Sub(*sp)))
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
*r = r.Intersect(mask.Bounds().Add(orig.Sub(*mp)))
}
if r.Dy() > dy {
r.Max.Y = r.Min.Y + dy
dx := r.Min.X - orig.X
dy := r.Min.Y - orig.Y
if dx == 0 && dy == 0 {
return
}
r = r.Intersect(dst.Bounds())
(*sp).X += dx
(*sp).Y += dy
(*mp).X += dx
(*mp).Y += dy
}
// 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) {
clip(dst, &r, src, &sp, mask, &mp)
if r.Empty() {
return
}
......
src/pkg/exp/draw/draw_test.go
View file @ ae5a972d
......@@ -263,8 +263,8 @@ func TestDrawOverlap(t *testing.T) {
}
}
// TestIssue836 verifies http://code.google.com/p/go/issues/detail?id=836.
func TestIssue836(t *testing.T) {
// TestNonZeroSrcPt checks drawing with a non-zero src point parameter.
func TestNonZeroSrcPt(t *testing.T) {
a := image.NewRGBA(1, 1)
b := image.NewRGBA(2, 2)
b.Set(0, 0, image.RGBAColor{0, 0, 0, 5})
......@@ -273,6 +273,6 @@ func TestIssue836(t *testing.T) {
b.Set(1, 1, image.RGBAColor{5, 0, 0, 5})
Draw(a, image.Rect(0, 0, 1, 1), b, image.Pt(1, 1))
if !eq(image.RGBAColor{5, 0, 0, 5}, a.At(0, 0)) {
t.Errorf("Issue 836: want %v got %v", image.RGBAColor{5, 0, 0, 5}, a.At(0, 0))
t.Errorf("non-zero src pt: want %v got %v", image.RGBAColor{5, 0, 0, 5}, a.At(0, 0))
}
}
src/pkg/image/geom.go
View file @ ae5a972d
......@@ -192,8 +192,19 @@ func (r Rectangle) Overlaps(s Rectangle) bool {
// Contains returns whether r contains p.
func (r Rectangle) Contains(p Point) bool {
return p.X >= r.Min.X && p.X < r.Max.X &&
p.Y >= r.Min.Y && p.Y < r.Max.Y
return r.Min.X <= p.X && p.X < r.Max.X &&
r.Min.Y <= p.Y && p.Y < r.Max.Y
}
// ContainsRectangle returns whether r contains every point in s.
func (r Rectangle) ContainsRectangle(s Rectangle) bool {
if s.Empty() {
return true
}
// Note that s.Max is an exclusive bound for s, so that r.ContainsRectangle(s)
// does not require that r.Contains(s.Max).
return r.Min.X <= s.Min.X && s.Max.X <= r.Max.X &&
r.Min.Y <= s.Min.Y && s.Max.Y <= r.Max.Y
}
// Canon returns the canonical version of r. The returned rectangle has minimum
......
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