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fix bugs in path contains

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Pull out the logic to check to see if the point is on the edge
so all curve types can share.

Reorder cubic to be like conic and quad so that mixed types
consider the curves consistently.

Don't count on curve points twice if they are on the end
and compute a zero cross product.

Remove logic that checks, when there are no roots, if the
point is closer to the top or the bottom (it's always the top).

Initialize the iterator correctly when it is accessing
the list of on point curves.

Use 'multiply' instead of 'subtract' to see if the vectors
are pointing in opposite directions.

Add more test cases.

R=reed@google.com,fs@opera.com
BUG=skia:4265
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1532003004

Review URL: https://codereview.chromium.org/1532003004
This commit is contained in:
caryclark 2015-12-18 04:35:24 -08:00 committed by Commit bot
parent c8b4336444
commit 9cb5d755e7
2 changed files with 65 additions and 29 deletions
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82
src/core/SkPath.cpp
View File

@ -2621,19 +2621,34 @@ template <size_t N> static void find_minmax(const SkPoint pts[],
*maxPtr = max;
}
static bool checkOnCurve(SkScalar x, SkScalar y, const SkPoint& start, const SkPoint& end) {
if (start.fY == end.fY) {
return between(start.fX, x, end.fX) && x != end.fX;
} else {
return x == start.fX && y == start.fY;
}
}
static int winding_mono_cubic(const SkPoint pts[], SkScalar x, SkScalar y, int* onCurveCount) {
if (!between(pts[0].fY, y, pts[3].fY)) {
SkScalar y0 = pts[0].fY;
SkScalar y3 = pts[3].fY;
int dir = 1;
if (y0 > y3) {
SkTSwap(y0, y3);
dir = -1;
}
if (y < y0 || y > y3) {
return 0;
}
if (y == pts[3].fY) {
// if the cubic is a horizontal line, check if the point is on it
// but don't check the last point, because that point is shared with the next curve
if (pts[0].fY == pts[3].fY && between(pts[0].fX, x, pts[3].fX) && x != pts[3].fX) {
*onCurveCount += 1;
}
if (checkOnCurve(x, y, pts[0], pts[3])) {
*onCurveCount += 1;
return 0;
}
int dir = pts[0].fY > pts[3].fY ? -1 : 1;
if (y == y3) {
return 0;
}
// quickreject or quickaccept
SkScalar min, max;
find_minmax<4>(pts, &min, &max);
@ -2651,6 +2666,7 @@ static int winding_mono_cubic(const SkPoint pts[], SkScalar x, SkScalar y, int*
if (SkScalarNearlyEqual(xt, x)) {
if (x != pts[3].fX || y != pts[3].fY) { // don't test end points; they're start points
*onCurveCount += 1;
return 0;
}
}
return xt < x ? dir : 0;
@ -2697,10 +2713,11 @@ static int winding_mono_conic(const SkConic& conic, SkScalar x, SkScalar y, int*
if (y < y0 || y > y2) {
return 0;
}
if (checkOnCurve(x, y, pts[0], pts[2])) {
*onCurveCount += 1;
return 0;
}
if (y == y2) {
if (y0 == y2 && between(pts[0].fX, x, pts[2].fX) && x != pts[2].fX) { // check horizontal
*onCurveCount += 1;
}
return 0;
}
@ -2715,10 +2732,10 @@ static int winding_mono_conic(const SkConic& conic, SkScalar x, SkScalar y, int*
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;
// zero roots are returned only when y0 == y
// Need [0] if dir == 1
// and [2] if dir == -1
xt = pts[1 - dir].fX;
} else {
SkScalar t = roots[0];
xt = conic_eval_numerator(&pts[0].fX, conic.fW, t) / conic_eval_denominator(conic.fW, t);
@ -2726,6 +2743,7 @@ static int winding_mono_conic(const SkConic& conic, SkScalar x, SkScalar y, int*
if (SkScalarNearlyEqual(xt, x)) {
if (x != pts[2].fX || y != pts[2].fY) { // don't test end points; they're start points
*onCurveCount += 1;
return 0;
}
}
return xt < x ? dir : 0;
@ -2773,10 +2791,11 @@ static int winding_mono_quad(const SkPoint pts[], SkScalar x, SkScalar y, int* o
if (y < y0 || y > y2) {
return 0;
}
if (checkOnCurve(x, y, pts[0], pts[2])) {
*onCurveCount += 1;
return 0;
}
if (y == y2) {
if (y0 == y2 && between(pts[0].fX, x, pts[2].fX) && x != pts[2].fX) { // check horizontal
*onCurveCount += 1;
}
return 0;
}
// bounds check on X (not required. is it faster?)
@ -2794,10 +2813,10 @@ static int winding_mono_quad(const SkPoint pts[], SkScalar x, SkScalar y, int* o
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;
// zero roots are returned only when y0 == y
// Need [0] if dir == 1
// and [2] if dir == -1
xt = pts[1 - dir].fX;
} else {
SkScalar t = roots[0];
SkScalar C = pts[0].fX;
@ -2808,6 +2827,7 @@ static int winding_mono_quad(const SkPoint pts[], SkScalar x, SkScalar y, int* o
if (SkScalarNearlyEqual(xt, x)) {
if (x != pts[2].fX || y != pts[2].fY) { // don't test end points; they're start points
*onCurveCount += 1;
return 0;
}
}
return xt < x ? dir : 0;
@ -2844,10 +2864,11 @@ static int winding_line(const SkPoint pts[], SkScalar x, SkScalar y, int* onCurv
if (y < y0 || y > y1) {
return 0;
}
if (y == pts[1].fY) {
if (y0 == y1 && between(x0, x, x1) && x != x1) { // check if on horizontal line
*onCurveCount += 1;
}
if (checkOnCurve(x, y, pts[0], pts[1])) {
*onCurveCount += 1;
return 0;
}
if (y == y1) {
return 0;
}
SkScalar cross = SkScalarMul(x1 - x0, y - pts[0].fY) - SkScalarMul(dy, x - x0);
@ -2856,7 +2877,9 @@ static int winding_line(const SkPoint pts[], SkScalar x, SkScalar y, int* onCurv
// zero cross means the point is on the line, and since the case where
// y of the query point is at the end point is handled above, we can be
// sure that we're on the line (excluding the end point) here
*onCurveCount += 1;
if (x != x1 || y != pts[1].fY) {
*onCurveCount += 1;
}
dir = 0;
} else if (SkScalarSignAsInt(cross) == dir) {
dir = 0;
@ -3023,6 +3046,7 @@ bool SkPath::contains(SkScalar x, SkScalar y) const {
// If the point touches an even number of curves, and the fill is winding, check for
// coincidence. Count coincidence as places where the on curve points have identical tangents.
iter.setPath(*this, true);
done = false;
SkTDArray<SkVector> tangents;
do {
SkPoint pts[4];
@ -3056,8 +3080,8 @@ bool SkPath::contains(SkScalar x, SkScalar y) const {
for (int index = 0; index < last; ++index) {
const SkVector& test = tangents[index];
if (SkScalarNearlyZero(test.cross(tangent))
&& SkScalarSignAsInt(tangent.fX - test.fX) <= 0
&& SkScalarSignAsInt(tangent.fY - test.fY) <= 0) {
&& SkScalarSignAsInt(tangent.fX * test.fX) <= 0
&& SkScalarSignAsInt(tangent.fY * test.fY) <= 0) {
tangents.remove(last);
tangents.removeShuffle(index);
break;

12
tests/PathTest.cpp
View File

@ -3591,6 +3591,10 @@ static void test_contains(skiatest::Reporter* reporter) {
REPORTER_ASSERT(reporter, p.contains(5, 5));
REPORTER_ASSERT(reporter, p.contains(5, 8));
REPORTER_ASSERT(reporter, p.contains(4, 5));
// test quad endpoints
REPORTER_ASSERT(reporter, p.contains(4, 4));
REPORTER_ASSERT(reporter, p.contains(8, 8));
REPORTER_ASSERT(reporter, p.contains(4, 8));
p.reset();
const SkPoint qPts[] = {{6, 6}, {8, 8}, {6, 8}, {4, 8}, {4, 6}, {4, 4}, {6, 6}};
@ -3622,6 +3626,10 @@ static void test_contains(skiatest::Reporter* reporter) {
halfway = conic.evalAt(0.5f);
REPORTER_ASSERT(reporter, p.contains(halfway.fX, halfway.fY));
}
// test conic end points
REPORTER_ASSERT(reporter, p.contains(4, 4));
REPORTER_ASSERT(reporter, p.contains(8, 8));
REPORTER_ASSERT(reporter, p.contains(4, 8));
// test cubics
SkPoint pts[] = {{5, 4}, {6, 5}, {7, 6}, {6, 6}, {4, 6}, {5, 7}, {5, 5}, {5, 4}, {6, 5}, {7, 6}};
@ -3639,6 +3647,10 @@ static void test_contains(skiatest::Reporter* reporter) {
REPORTER_ASSERT(reporter, p.contains(halfway.fX, halfway.fY));
SkEvalCubicAt(&pts[i + 3], 0.5f, &halfway, nullptr, nullptr);
REPORTER_ASSERT(reporter, p.contains(halfway.fX, halfway.fY));
// test cubic end points
REPORTER_ASSERT(reporter, p.contains(pts[i].fX, pts[i].fY));
REPORTER_ASSERT(reporter, p.contains(pts[i + 3].fX, pts[i + 3].fY));
REPORTER_ASSERT(reporter, p.contains(pts[i + 6].fX, pts[i + 6].fY));
}
}