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add SkPath::contains(x, y)

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git-svn-id: http://skia.googlecode.com/svn/trunk@4526 2bbb7eff-a529-9590-31e7-b0007b416f81
This commit is contained in:
mike@reedtribe.org 2012-07-11 01:51:33 +00:00
parent 927ee823fc
commit bad1b2ff1d
5 changed files with 271 additions and 273 deletions
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36
gm/hittestpath.cpp
View File

@ -10,7 +10,7 @@
#include "SkCullPoints.h"
#include "SkRandom.h"
static void test_hittest(SkCanvas* canvas, const SkPath& path, bool hires) {
static void test_hittest(SkCanvas* canvas, const SkPath& path) {
SkPaint paint;
SkRect r = path.getBounds();
@ -22,14 +22,8 @@ static void test_hittest(SkCanvas* canvas, const SkPath& path, bool hires) {
paint.setColor(0x800000FF);
for (SkScalar y = r.fTop + SK_ScalarHalf - MARGIN; y < r.fBottom + MARGIN; y += SK_Scalar1) {
for (SkScalar x = r.fLeft + SK_ScalarHalf - MARGIN; x < r.fRight + MARGIN; x += SK_Scalar1) {
if (hires) {
if (SkHitTestPathEx(path, x, y)) {
canvas->drawPoint(x, y, paint);
}
} else {
if (SkHitTestPath(path, x, y, false)) {
canvas->drawPoint(x, y, paint);
}
if (path.contains(x, y)) {
canvas->drawPoint(x, y, paint);
}
}
}
@ -50,25 +44,25 @@ protected:
SkPath path;
SkRandom rand;
for (int i = 0; i < 5; ++i) {
path.lineTo(rand.nextUScalar1() * 150, rand.nextUScalar1() * 150);
path.quadTo(rand.nextUScalar1() * 150, rand.nextUScalar1() * 150,
rand.nextUScalar1() * 150, rand.nextUScalar1() * 150);
int scale = 300;
for (int i = 0; i < 4; ++i) {
path.lineTo(rand.nextUScalar1() * scale, rand.nextUScalar1() * scale);
path.quadTo(rand.nextUScalar1() * scale, rand.nextUScalar1() * scale,
rand.nextUScalar1() * scale, rand.nextUScalar1() * scale);
path.cubicTo(rand.nextUScalar1() * scale, rand.nextUScalar1() * scale,
rand.nextUScalar1() * scale, rand.nextUScalar1() * scale,
rand.nextUScalar1() * scale, rand.nextUScalar1() * scale);
}
path.setFillType(SkPath::kEvenOdd_FillType);
path.offset(SkIntToScalar(20), SkIntToScalar(20));
test_hittest(canvas, path, false);
canvas->translate(SkIntToScalar(200), 0);
test_hittest(canvas, path, true);
canvas->translate(-SkIntToScalar(200), SkIntToScalar(200));
test_hittest(canvas, path);
canvas->translate(SkIntToScalar(scale), 0);
path.setFillType(SkPath::kWinding_FillType);
test_hittest(canvas, path, false);
canvas->translate(SkIntToScalar(200), 0);
test_hittest(canvas, path, true);
test_hittest(canvas, path);
}
private:

6
include/core/SkPath.h
View File

@ -781,6 +781,12 @@ public:
SkPoint fLastPt;
};
/**
* Returns true if the point { x, y } is contained by the path, taking into
* account the FillType.
*/
bool contains(SkScalar x, SkScalar y) const;
void dump(bool forceClose, const char title[] = NULL) const;
void dump() const;

1
include/utils/SkCullPoints.h
View File

@ -67,6 +67,5 @@ private:
bool SkHitTestPath(const SkPath&, SkRect& target, bool hires);
bool SkHitTestPath(const SkPath&, SkScalar x, SkScalar y, bool hires);
bool SkHitTestPathEx(const SkPath&, SkScalar x, SkScalar y);
#endif

250
src/core/SkPath.cpp
View File

@ -2255,3 +2255,253 @@ bool SkPath::cheapComputeDirection(Direction* dir) const {
return ymaxCross ? crossToDir(ymaxCross, dir) : false;
}
///////////////////////////////////////////////////////////////////////////////
static SkScalar eval_cubic_coeff(SkScalar A, SkScalar B, SkScalar C,
SkScalar D, SkScalar t) {
return SkScalarMulAdd(SkScalarMulAdd(SkScalarMulAdd(A, t, B), t, C), t, D);
}
static SkScalar eval_cubic_pts(SkScalar c0, SkScalar c1, SkScalar c2, SkScalar c3,
SkScalar t) {
SkScalar A = c3 + 3*(c1 - c2) - c0;
SkScalar B = 3*(c2 - c1 - c1 + c0);
SkScalar C = 3*(c1 - c0);
SkScalar D = c0;
return eval_cubic_coeff(A, B, C, D, t);
}
/* Given 4 cubic points (either Xs or Ys), and a target X or Y, compute the
t value such that cubic(t) = target
*/
static bool chopMonoCubicAt(SkScalar c0, SkScalar c1, SkScalar c2, SkScalar c3,
SkScalar target, SkScalar* t) {
// SkASSERT(c0 <= c1 && c1 <= c2 && c2 <= c3);
SkASSERT(c0 < target && target < c3);
SkScalar D = c0 - target;
SkScalar A = c3 + 3*(c1 - c2) - c0;
SkScalar B = 3*(c2 - c1 - c1 + c0);
SkScalar C = 3*(c1 - c0);
const SkScalar TOLERANCE = SK_Scalar1 / 4096;
SkScalar minT = 0;
SkScalar maxT = SK_Scalar1;
SkScalar mid;
int i;
for (i = 0; i < 16; i++) {
mid = SkScalarAve(minT, maxT);
SkScalar delta = eval_cubic_coeff(A, B, C, D, mid);
if (delta < 0) {
minT = mid;
delta = -delta;
} else {
maxT = mid;
}
if (delta < TOLERANCE) {
break;
}
}
*t = mid;
return true;
}
template <size_t N> static void find_minmax(const SkPoint pts[],
SkScalar* minPtr, SkScalar* maxPtr) {
SkScalar min, max;
min = max = pts[0].fX;
for (size_t i = 1; i < N; ++i) {
min = SkMinScalar(min, pts[i].fX);
max = SkMaxScalar(max, pts[i].fX);
}
*minPtr = min;
*maxPtr = max;
}
static int winding_mono_cubic(const SkPoint pts[], SkScalar x, SkScalar y) {
SkPoint storage[4];
int dir = 1;
if (pts[0].fY > pts[3].fY) {
storage[0] = pts[3];
storage[1] = pts[2];
storage[2] = pts[1];
storage[3] = pts[0];
pts = storage;
dir = -1;
}
if (y < pts[0].fY || y >= pts[3].fY) {
return 0;
}
// quickreject or quickaccept
SkScalar min, max;
find_minmax<4>(pts, &min, &max);
if (x < min) {
return 0;
}
if (x > max) {
return dir;
}
// compute the actual x(t) value
SkScalar t, xt;
if (chopMonoCubicAt(pts[0].fY, pts[1].fY, pts[2].fY, pts[3].fY, y, &t)) {
xt = eval_cubic_pts(pts[0].fX, pts[1].fX, pts[2].fX, pts[3].fX, t);
} else {
SkScalar mid = SkScalarAve(pts[0].fY, pts[3].fY);
xt = y < mid ? pts[0].fX : pts[3].fX;
}
return xt < x ? dir : 0;
}
static int winding_cubic(const SkPoint pts[], SkScalar x, SkScalar y) {
SkPoint dst[10];
int n = SkChopCubicAtYExtrema(pts, dst);
int w = 0;
for (int i = 0; i <= n; ++i) {
w += winding_mono_cubic(&dst[i * 3], x, y);
}
return w;
}
static int winding_mono_quad(const SkPoint pts[], SkScalar x, SkScalar y) {
SkScalar y0 = pts[0].fY;
SkScalar y2 = pts[2].fY;
int dir = 1;
if (y0 > y2) {
SkTSwap(y0, y2);
dir = -1;
}
if (y < y0 || y >= y2) {
return 0;
}
// bounds check on X (not required. is it faster?)
#if 0
if (pts[0].fX > x && pts[1].fX > x && pts[2].fX > x) {
return 0;
}
#endif
SkScalar roots[2];
int n = SkFindUnitQuadRoots(pts[0].fY - 2 * pts[1].fY + pts[2].fY,
2 * (pts[1].fY - pts[0].fY),
pts[0].fY - y,
roots);
SkASSERT(n <= 1);
SkScalar xt;
if (0 == n) {
SkScalar mid = SkScalarAve(y0, y2);
// Need [0] and [2] if dir == 1
// and [2] and [0] if dir == -1
xt = y < mid ? pts[1 - dir].fX : pts[dir - 1].fX;
} else {
SkScalar t = roots[0];
SkScalar C = pts[0].fX;
SkScalar A = pts[2].fX - 2 * pts[1].fX + C;
SkScalar B = 2 * (pts[1].fX - C);
xt = SkScalarMulAdd(SkScalarMulAdd(A, t, B), t, C);
}
return xt < x ? dir : 0;
}
static bool is_mono_quad(SkScalar y0, SkScalar y1, SkScalar y2) {
// return SkScalarSignAsInt(y0 - y1) + SkScalarSignAsInt(y1 - y2) != 0;
if (y0 == y1) {
return true;
}
if (y0 < y1) {
return y1 <= y2;
} else {
return y1 >= y2;
}
}
static int winding_quad(const SkPoint pts[], SkScalar x, SkScalar y) {
SkPoint dst[5];
int n = 0;
if (!is_mono_quad(pts[0].fY, pts[1].fY, pts[2].fY)) {
n = SkChopQuadAtYExtrema(pts, dst);
pts = dst;
}
int w = winding_mono_quad(pts, x, y);
if (n > 0) {
w += winding_mono_quad(&pts[2], x, y);
}
return w;
}
static int winding_line(const SkPoint pts[], SkScalar x, SkScalar y) {
SkScalar x0 = pts[0].fX;
SkScalar y0 = pts[0].fY;
SkScalar x1 = pts[1].fX;
SkScalar y1 = pts[1].fY;
SkScalar dy = y1 - y0;
int dir = 1;
if (y0 > y1) {
SkTSwap(y0, y1);
dir = -1;
}
if (y < y0 || y >= y1) {
return 0;
}
SkScalar cross = SkScalarMul(x1 - x0, y - pts[0].fY) -
SkScalarMul(dy, x - pts[0].fX);
if (SkScalarSignAsInt(cross) == dir) {
dir = 0;
}
return dir;
}
bool SkPath::contains(SkScalar x, SkScalar y) const {
bool isInverse = this->isInverseFillType();
if (this->isEmpty()) {
return isInverse;
}
const SkRect& bounds = this->getBounds();
if (!bounds.contains(x, y)) {
return isInverse;
}
SkPath::Iter iter(*this, true);
bool done = false;
int w = 0;
do {
SkPoint pts[4];
switch (iter.next(pts, false)) {
case SkPath::kMove_Verb:
case SkPath::kClose_Verb:
break;
case SkPath::kLine_Verb:
w += winding_line(pts, x, y);
break;
case SkPath::kQuad_Verb:
w += winding_quad(pts, x, y);
break;
case SkPath::kCubic_Verb:
w += winding_cubic(pts, x, y);
break;
case SkPath::kDone_Verb:
done = true;
break;
}
} while (!done);
switch (this->getFillType()) {
case SkPath::kEvenOdd_FillType:
case SkPath::kInverseEvenOdd_FillType:
w &= 1;
break;
}
return SkToBool(w);
}

251
src/utils/SkCullPoints.cpp
View File

@ -218,254 +218,3 @@ bool SkHitTestPath(const SkPath& path, SkScalar x, SkScalar y, bool hires) {
return SkHitTestPath(path, r, hires);
}
///////////////////////////////////////////////////////////////////////////////
#include "SkGeometry.h"
static SkScalar eval_cubic_coeff(SkScalar A, SkScalar B, SkScalar C,
SkScalar D, SkScalar t) {
return SkScalarMulAdd(SkScalarMulAdd(SkScalarMulAdd(A, t, B), t, C), t, D);
}
static SkScalar eval_cubic_pts(SkScalar c0, SkScalar c1, SkScalar c2, SkScalar c3,
SkScalar t) {
SkScalar A = c3 + 3*(c1 - c2) - c0;
SkScalar B = 3*(c2 - c1 - c1 + c0);
SkScalar C = 3*(c1 - c0);
SkScalar D = c0;
return eval_cubic_coeff(A, B, C, D, t);
}
/* Given 4 cubic points (either Xs or Ys), and a target X or Y, compute the
t value such that cubic(t) = target
*/
static bool chopMonoCubicAt(SkScalar c0, SkScalar c1, SkScalar c2, SkScalar c3,
SkScalar target, SkScalar* t) {
// SkASSERT(c0 <= c1 && c1 <= c2 && c2 <= c3);
SkASSERT(c0 < target && target < c3);
SkScalar D = c0 - target;
SkScalar A = c3 + 3*(c1 - c2) - c0;
SkScalar B = 3*(c2 - c1 - c1 + c0);
SkScalar C = 3*(c1 - c0);
const SkScalar TOLERANCE = SK_Scalar1 / 4096;
SkScalar minT = 0;
SkScalar maxT = SK_Scalar1;
SkScalar mid;
int i;
for (i = 0; i < 16; i++) {
mid = SkScalarAve(minT, maxT);
SkScalar delta = eval_cubic_coeff(A, B, C, D, mid);
if (delta < 0) {
minT = mid;
delta = -delta;
} else {
maxT = mid;
}
if (delta < TOLERANCE) {
break;
}
}
*t = mid;
return true;
}
template <size_t N> static void find_minmax(const SkPoint pts[],
SkScalar* minPtr, SkScalar* maxPtr) {
SkScalar min, max;
min = max = pts[0].fX;
for (size_t i = 1; i < N; ++i) {
min = SkMinScalar(min, pts[i].fX);
max = SkMaxScalar(max, pts[i].fX);
}
*minPtr = min;
*maxPtr = max;
}
static int winding_mono_cubic(const SkPoint pts[], SkScalar x, SkScalar y) {
SkPoint storage[4];
int dir = 1;
if (pts[0].fY > pts[3].fY) {
storage[0] = pts[3];
storage[1] = pts[2];
storage[2] = pts[1];
storage[3] = pts[0];
pts = storage;
dir = -1;
}
if (y < pts[0].fY || y >= pts[3].fY) {
return 0;
}
// quickreject or quickaccept
SkScalar min, max;
find_minmax<4>(pts, &min, &max);
if (x < min) {
return 0;
}
if (x > max) {
return dir;
}
// compute the actual x(t) value
SkScalar t, xt;
if (chopMonoCubicAt(pts[0].fY, pts[1].fY, pts[2].fY, pts[3].fY, y, &t)) {
xt = eval_cubic_pts(pts[0].fX, pts[1].fX, pts[2].fX, pts[3].fX, t);
} else {
SkScalar mid = SkScalarAve(pts[0].fY, pts[3].fY);
xt = y < mid ? pts[0].fX : pts[3].fX;
}
return xt < x ? dir : 0;
}
static int winding_cubic(const SkPoint pts[], SkScalar x, SkScalar y) {
SkPoint dst[10];
int n = SkChopCubicAtYExtrema(pts, dst);
int w = 0;
for (int i = 0; i <= n; ++i) {
w += winding_mono_cubic(&dst[i * 3], x, y);
}
return w;
}
static int winding_mono_quad(const SkPoint pts[], SkScalar x, SkScalar y) {
SkScalar y0 = pts[0].fY;
SkScalar y2 = pts[2].fY;
int dir = 1;
if (y0 > y2) {
SkTSwap(y0, y2);
dir = -1;
}
if (y < y0 || y >= y2) {
return 0;
}
// bounds check on X (not required, but maybe faster)
#if 0
if (pts[0].fX > x && pts[1].fX > x && pts[2].fX > x) {
return 0;
}
#endif
SkScalar roots[2];
int n = SkFindUnitQuadRoots(pts[0].fY - 2 * pts[1].fY + pts[2].fY,
2 * (pts[1].fY - pts[0].fY),
pts[0].fY - y,
roots);
SkASSERT(n <= 1);
SkScalar xt;
if (0 == n) {
SkScalar mid = SkScalarAve(y0, y2);
// Need [0] and [2] if dir == 1
// and [2] and [0] if dir == -1
xt = y < mid ? pts[1 - dir].fX : pts[dir - 1].fX;
} else {
SkScalar t = roots[0];
SkScalar C = pts[0].fX;
SkScalar A = pts[2].fX - 2 * pts[1].fX + C;
SkScalar B = 2 * (pts[1].fX - C);
xt = SkScalarMulAdd(SkScalarMulAdd(A, t, B), t, C);
}
return xt < x ? dir : 0;
}
static bool is_mono_quad(SkScalar y0, SkScalar y1, SkScalar y2) {
// return SkScalarSignAsInt(y0 - y1) + SkScalarSignAsInt(y1 - y2) != 0;
if (y0 == y1) {
return true;
}
if (y0 < y1) {
return y1 <= y2;
} else {
return y1 >= y2;
}
}
static int winding_quad(const SkPoint pts[], SkScalar x, SkScalar y) {
SkPoint dst[5];
int n = 0;
if (!is_mono_quad(pts[0].fY, pts[1].fY, pts[2].fY)) {
n = SkChopQuadAtYExtrema(pts, dst);
pts = dst;
}
int w = winding_mono_quad(pts, x, y);
if (n > 0) {
w += winding_mono_quad(&pts[2], x, y);
}
return w;
}
static int winding_line(const SkPoint pts[], SkScalar x, SkScalar y) {
SkScalar x0 = pts[0].fX;
SkScalar y0 = pts[0].fY;
SkScalar x1 = pts[1].fX;
SkScalar y1 = pts[1].fY;
SkScalar dy = y1 - y0;
int dir = 1;
if (y0 > y1) {
SkTSwap(y0, y1);
dir = -1;
}
if (y < y0 || y >= y1) {
return 0;
}
SkScalar cross = SkScalarMul(x1 - x0, y - pts[0].fY) -
SkScalarMul(dy, x - pts[0].fX);
if (SkScalarSignAsInt(cross) == dir) {
dir = 0;
}
return dir;
}
bool SkHitTestPathEx(const SkPath& path, SkScalar x, SkScalar y) {
bool isInverse = path.isInverseFillType();
if (path.isEmpty()) {
return isInverse;
}
const SkRect& bounds = path.getBounds();
if (!bounds.contains(x, y)) {
return isInverse;
}
SkPath::Iter iter(path, true);
bool done = false;
int w = 0;
do {
SkPoint pts[4];
switch (iter.next(pts, false)) {
case SkPath::kMove_Verb:
case SkPath::kClose_Verb:
break;
case SkPath::kLine_Verb:
w += winding_line(pts, x, y);
break;
case SkPath::kQuad_Verb:
w += winding_quad(pts, x, y);
break;
case SkPath::kCubic_Verb:
w += winding_cubic(pts, x, y);
break;
case SkPath::kDone_Verb:
done = true;
break;
}
} while (!done);
switch (path.getFillType()) {
case SkPath::kEvenOdd_FillType:
case SkPath::kInverseEvenOdd_FillType:
w &= 1;
break;
}
return SkToBool(w);
}