зеркало из https://github.com/mozilla/moz-skia.git
add explicit clamping after chopping w/ t to ensure we're in the clip
git-svn-id: http://skia.googlecode.com/svn/trunk@430 2bbb7eff-a529-9590-31e7-b0007b416f81
This commit is contained in:
reed@android.com
Родитель
77f0ef726f
Коммит
3a0cd7f0e8
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@ -34,6 +34,23 @@ static void check_clipper(int count, const SkPoint pts[], const SkRect& clip) {
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SkASSERT(pts[i].fY >= clip.fTop);
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SkASSERT(pts[i].fY <= clip.fBottom);
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}
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if (count > 1) {
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// now check that we're monotonic in Y
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if (pts[0].fY > pts[count - 1].fY) {
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for (int i = 1; i < count; i++) {
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SkASSERT(pts[i - 1].fY >= pts[i].fY);
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}
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} else if (pts[0].fY < pts[count - 1].fY) {
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for (int i = 1; i < count; i++) {
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SkASSERT(pts[i - 1].fY <= pts[i].fY);
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}
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} else {
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for (int i = 1; i < count; i++) {
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SkASSERT(pts[i - 1].fY == pts[i].fY);
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}
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}
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}
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}
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static void line_clipper(const SkPoint src[], const SkRect& clip,
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@ -59,9 +76,11 @@ static void quad_clipper(const SkPoint src[], const SkRect& clip,
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while ((verb = clipper.next(pts)) != SkPath::kDone_Verb) {
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switch (verb) {
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case SkPath::kLine_Verb:
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check_clipper(2, pts, clip);
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canvas->drawPoints(SkCanvas::kLines_PointMode, 2, pts, p0);
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break;
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case SkPath::kQuad_Verb:
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check_clipper(3, pts, clip);
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drawQuad(canvas, pts, p0);
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break;
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default:
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@ -84,6 +103,7 @@ enum {
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};
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class LineClipperView : public SkView {
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int fCounter;
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int fProcIndex;
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SkRect fClip;
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SkRandom fRand;
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@ -94,16 +114,18 @@ class LineClipperView : public SkView {
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fPts[i].set(fRand.nextUScalar1() * 640,
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fRand.nextUScalar1() * 480);
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}
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fCounter += 1;
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}
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public:
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LineClipperView() {
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fProcIndex = 1;
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fCounter = 0;
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int x = (640 - W)/2;
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int y = (480 - H)/2;
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fClip.set(x, y, x + W, y + H);
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this->randPts();
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fProcIndex = 1;
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}
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protected:
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@ -17,6 +17,22 @@
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#include "SkQuadClipper.h"
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#include "SkGeometry.h"
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static bool quick_reject(const SkRect& bounds, const SkRect& clip) {
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return bounds.fTop >= clip.fBottom || bounds.fBottom <= clip.fTop;
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}
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static inline void clamp_le(SkScalar& value, SkScalar max) {
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if (value > max) {
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value = max;
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}
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}
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static inline void clamp_ge(SkScalar& value, SkScalar min) {
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if (value < min) {
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value = min;
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}
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}
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static bool chopMonoQuadAt(SkScalar c0, SkScalar c1, SkScalar c2,
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SkScalar target, SkScalar* t) {
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/* Solve F(t) = y where F(t) := [0](1-t)^2 + 2[1]t(1-t) + [2]t^2
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@ -132,6 +148,8 @@ static void chop_quad_in_Y(SkPoint pts[3], const SkRect& clip) {
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if (chopMonoQuadAtY(pts, clip.fTop, &t)) {
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// take the 2nd chopped quad
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SkChopQuadAt(pts, tmp, t);
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clamp_ge(tmp[2].fY, clip.fTop);
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clamp_ge(tmp[3].fY, clip.fTop);
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pts[0] = tmp[2];
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pts[1] = tmp[3];
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} else {
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@ -149,6 +167,8 @@ static void chop_quad_in_Y(SkPoint pts[3], const SkRect& clip) {
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if (pts[2].fY > clip.fBottom) {
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if (chopMonoQuadAtY(pts, clip.fBottom, &t)) {
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SkChopQuadAt(pts, tmp, t);
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clamp_le(tmp[1].fY, clip.fBottom);
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clamp_le(tmp[2].fY, clip.fBottom);
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pts[1] = tmp[1];
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pts[2] = tmp[2];
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} else {
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@ -223,6 +243,8 @@ void SkQuadClipper2::clipMonoQuad(const SkPoint srcPts[3], const SkRect& clip) {
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if (chopMonoQuadAtX(pts, clip.fLeft, &t)) {
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SkChopQuadAt(pts, tmp, t);
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this->appendVLine(clip.fLeft, tmp[0].fY, tmp[2].fY, reverse);
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clamp_ge(tmp[2].fX, clip.fLeft);
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clamp_ge(tmp[3].fX, clip.fLeft);
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pts[0] = tmp[2];
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pts[1] = tmp[3];
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} else {
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@ -236,6 +258,8 @@ void SkQuadClipper2::clipMonoQuad(const SkPoint srcPts[3], const SkRect& clip) {
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if (pts[2].fX > clip.fRight) {
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if (chopMonoQuadAtX(pts, clip.fRight, &t)) {
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SkChopQuadAt(pts, tmp, t);
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clamp_le(tmp[1].fX, clip.fRight);
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clamp_le(tmp[2].fX, clip.fRight);
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this->appendQuad(tmp, reverse);
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this->appendVLine(clip.fRight, tmp[2].fY, tmp[4].fY, reverse);
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} else {
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@ -248,21 +272,14 @@ void SkQuadClipper2::clipMonoQuad(const SkPoint srcPts[3], const SkRect& clip) {
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}
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}
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static bool quick_reject_quad(const SkPoint srcPts[3], const SkRect& clip) {
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return (srcPts[0].fY <= clip.fTop &&
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srcPts[1].fY <= clip.fTop &&
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srcPts[2].fY <= clip.fTop)
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(srcPts[0].fY >= clip.fBottom &&
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srcPts[1].fY >= clip.fBottom &&
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srcPts[2].fY >= clip.fBottom);
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}
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bool SkQuadClipper2::clipQuad(const SkPoint srcPts[3], const SkRect& clip) {
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fCurrPoint = fPoints;
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fCurrVerb = fVerbs;
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if (!quick_reject_quad(srcPts, clip)) {
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SkRect bounds;
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bounds.set(srcPts, 3);
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if (!quick_reject(bounds, clip)) {
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SkPoint monoY[5];
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int countY = SkChopQuadAtYExtrema(srcPts, monoY);
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for (int y = 0; y <= countY; y++) {
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@ -283,6 +300,38 @@ bool SkQuadClipper2::clipQuad(const SkPoint srcPts[3], const SkRect& clip) {
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return SkPath::kDone_Verb != fVerbs[0];
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}
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///////////////////////////////////////////////////////////////////////////////
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bool SkQuadClipper2::clipCubic(const SkPoint srcPts[4], const SkRect& clip) {
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fCurrPoint = fPoints;
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fCurrVerb = fVerbs;
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SkRect bounds;
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bounds.set(srcPts, 4);
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if (!quick_reject(bounds, clip)) {
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SkPoint monoY[5];
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int countY = SkChopQuadAtYExtrema(srcPts, monoY);
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for (int y = 0; y <= countY; y++) {
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SkPoint monoX[5];
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int countX = SkChopQuadAtXExtrema(&monoY[y * 2], monoX);
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SkASSERT(countY + countX <= 3);
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for (int x = 0; x <= countX; x++) {
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this->clipMonoQuad(&monoX[x * 2], clip);
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SkASSERT(fCurrVerb - fVerbs < kMaxVerbs);
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SkASSERT(fCurrPoint - fPoints <= kMaxPoints);
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}
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}
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}
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*fCurrVerb = SkPath::kDone_Verb;
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fCurrPoint = fPoints;
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fCurrVerb = fVerbs;
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return SkPath::kDone_Verb != fVerbs[0];
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}
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///////////////////////////////////////////////////////////////////////////////
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void SkQuadClipper2::appendVLine(SkScalar x, SkScalar y0, SkScalar y1,
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bool reverse) {
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*fCurrVerb++ = SkPath::kLine_Verb;
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@ -297,7 +346,7 @@ void SkQuadClipper2::appendVLine(SkScalar x, SkScalar y0, SkScalar y1,
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void SkQuadClipper2::appendQuad(const SkPoint pts[3], bool reverse) {
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*fCurrVerb++ = SkPath::kQuad_Verb;
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if (reverse) {
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fCurrPoint[0] = pts[2];
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fCurrPoint[2] = pts[0];
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@ -309,6 +358,19 @@ void SkQuadClipper2::appendQuad(const SkPoint pts[3], bool reverse) {
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fCurrPoint += 3;
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}
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void SkQuadClipper2::appendCubic(const SkPoint pts[4], bool reverse) {
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*fCurrVerb++ = SkPath::kCubic_Verb;
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if (reverse) {
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for (int i = 0; i < 4; i++) {
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fCurrPoint[i] = pts[3 - i];
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}
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} else {
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memcpy(fCurrPoint, pts, 4 * sizeof(SkPoint));
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}
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fCurrPoint += 4;
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}
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SkPath::Verb SkQuadClipper2::next(SkPoint pts[]) {
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SkPath::Verb verb = *fCurrVerb;
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@ -323,6 +385,11 @@ SkPath::Verb SkQuadClipper2::next(SkPoint pts[]) {
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fCurrPoint += 3;
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fCurrVerb += 1;
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break;
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case SkPath::kCubic_Verb:
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memcpy(pts, fCurrPoint, 4 * sizeof(SkPoint));
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fCurrPoint += 4;
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fCurrVerb += 1;
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break;
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case SkPath::kDone_Verb:
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break;
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default:
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@ -44,6 +44,7 @@ private:
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class SkQuadClipper2 {
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public:
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bool clipQuad(const SkPoint pts[3], const SkRect& clip);
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bool clipCubic(const SkPoint pts[4], const SkRect& clip);
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SkPath::Verb next(SkPoint pts[]);
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@ -61,6 +62,7 @@ private:
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void clipMonoQuad(const SkPoint srcPts[3], const SkRect& clip);
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void appendVLine(SkScalar x, SkScalar y0, SkScalar y1, bool reverse);
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void appendQuad(const SkPoint pts[3], bool reverse);
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void appendCubic(const SkPoint pts[4], bool reverse);
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};
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#endif
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