Add base types for path ops
Paths contain lines, quads, and cubics, which are
collectively curves.
To work with path intersections, intermediary curves
are constructed. For now, those intermediates use
doubles to guarantee sufficient precision.
The DVector, DPoint, DLine, DQuad, and DCubic
structs encapsulate these intermediate curves.
The DRect and DTriangle structs are created to
describe intersectable areas of interest.
The Bounds struct inherits from SkRect to create
a SkScalar-based rectangle that intersects shared
edges.
This also includes common math equalities and
debugging that the remainder of path ops builds on,
as well as a temporary top-level interface in
include/pathops/SkPathOps.h.
Review URL: https://codereview.chromium.org/12827020
git-svn-id: http://skia.googlecode.com/svn/trunk@8551 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/pathops/SkIntersections.cpp b/src/pathops/SkIntersections.cpp
new file mode 100644
index 0000000..205308f
--- /dev/null
+++ b/src/pathops/SkIntersections.cpp
@@ -0,0 +1,261 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkIntersections.h"
+
+int (SkIntersections::*CurveVertical[])(const SkPoint[], SkScalar, SkScalar, SkScalar, bool) = {
+ NULL,
+ &SkIntersections::verticalLine,
+ &SkIntersections::verticalQuad,
+ &SkIntersections::verticalCubic
+};
+
+int (SkIntersections::*CurveRay[])(const SkPoint[], const SkDLine&) = {
+ NULL,
+ NULL,
+ &SkIntersections::quadRay,
+ &SkIntersections::cubicRay
+};
+
+int SkIntersections::coincidentUsed() const {
+ if (!fIsCoincident[0]) {
+ SkASSERT(!fIsCoincident[0]);
+ return 0;
+ }
+ int count = 0;
+ SkDEBUGCODE(int count2 = 0;)
+ for (int index = 0; index < fUsed; ++index) {
+ if (fIsCoincident[0] & (1 << index)) {
+ ++count;
+ }
+#ifdef SK_DEBUG
+ if (fIsCoincident[1] & (1 << index)) {
+ ++count2;
+ }
+#endif
+ }
+ SkASSERT(count == count2);
+ return count;
+}
+
+int SkIntersections::cubicRay(const SkPoint pts[4], const SkDLine& line) {
+ SkDCubic cubic;
+ cubic.set(pts);
+ return intersectRay(cubic, line);
+}
+
+void SkIntersections::flip() {
+ for (int index = 0; index < fUsed; ++index) {
+ fT[1][index] = 1 - fT[1][index];
+ }
+}
+
+void SkIntersections::insertCoincidentPair(double s1, double e1, double s2, double e2,
+ const SkDPoint& startPt, const SkDPoint& endPt) {
+ if (fSwap) {
+ remove(s2, e2, startPt, endPt);
+ } else {
+ remove(s1, e1, startPt, endPt);
+ }
+ SkASSERT(coincidentUsed() == fUsed);
+ SkASSERT((coincidentUsed() & 1) != 1);
+ int i1 = 0;
+ int i2 = 0;
+ do {
+ while (i1 < fUsed && !(fIsCoincident[fSwap] & (1 << i1))) {
+ ++i1;
+ }
+ if (i1 == fUsed) {
+ break;
+ }
+ SkASSERT(i1 < fUsed);
+ int iEnd1 = i1 + 1;
+ while (!(fIsCoincident[fSwap] & (1 << iEnd1))) {
+ ++iEnd1;
+ }
+ SkASSERT(iEnd1 < fUsed);
+ double cs1 = fT[fSwap][i1];
+ double ce1 = fT[fSwap][iEnd1];
+ bool s1in = between(cs1, s1, ce1) || startPt.approximatelyEqual(fPt[i1])
+ || startPt.approximatelyEqual(fPt[iEnd1]);
+ bool e1in = between(cs1, e1, ce1) || endPt.approximatelyEqual(fPt[i1])
+ || endPt.approximatelyEqual(fPt[iEnd1]);
+ while (i2 < fUsed && !(fIsCoincident[fSwap ^ 1] & (1 << i2))) {
+ ++i2;
+ }
+ int iEnd2 = i2 + 1;
+ while (!(fIsCoincident[fSwap ^ 1] & (1 << iEnd2))) {
+ ++iEnd2;
+ }
+ SkASSERT(iEnd2 < fUsed);
+ double cs2 = fT[fSwap ^ 1][i2];
+ double ce2 = fT[fSwap ^ 1][iEnd2];
+ bool s2in = between(cs2, s2, ce2) || startPt.approximatelyEqual(fPt[i2])
+ || startPt.approximatelyEqual(fPt[iEnd2]);
+ bool e2in = between(cs2, e2, ce2) || endPt.approximatelyEqual(fPt[i2])
+ || endPt.approximatelyEqual(fPt[iEnd2]);
+ if ((s1in | e1in) & (s2in | e2in)) {
+ if (s1 < cs1) {
+ fT[fSwap][i1] = s1;
+ fPt[i1] = startPt;
+ } else if (e1 < cs1) {
+ fT[fSwap][i1] = e1;
+ fPt[i1] = endPt;
+ }
+ if (s1 > ce1) {
+ fT[fSwap][iEnd1] = s1;
+ fPt[iEnd1] = startPt;
+ } else if (e1 > ce1) {
+ fT[fSwap][iEnd1] = e1;
+ fPt[iEnd1] = endPt;
+ }
+ if (s2 > e2) {
+ SkTSwap(cs2, ce2);
+ SkTSwap(i2, iEnd2);
+ }
+ if (s2 < cs2) {
+ fT[fSwap ^ 1][i2] = s2;
+ } else if (e2 < cs2) {
+ fT[fSwap ^ 1][i2] = e2;
+ }
+ if (s2 > ce2) {
+ fT[fSwap ^ 1][iEnd2] = s2;
+ } else if (e2 > ce2) {
+ fT[fSwap ^ 1][iEnd2] = e2;
+ }
+ return;
+ }
+ } while (true);
+ SkASSERT(fUsed < 9);
+ insertCoincident(s1, s2, startPt);
+ insertCoincident(e1, e2, endPt);
+}
+
+int SkIntersections::insert(double one, double two, const SkDPoint& pt) {
+ SkASSERT(fUsed <= 1 || fT[0][0] <= fT[0][1]);
+ int index;
+ for (index = 0; index < fUsed; ++index) {
+ double oldOne = fT[0][index];
+ double oldTwo = fT[1][index];
+ if (roughly_equal(oldOne, one) && roughly_equal(oldTwo, two)) {
+ if ((precisely_zero(one) && !precisely_zero(oldOne))
+ || (precisely_equal(one, 1) && !precisely_equal(oldOne, 1))
+ || (precisely_zero(two) && !precisely_zero(oldTwo))
+ || (precisely_equal(two, 1) && !precisely_equal(oldTwo, 1))) {
+ fT[0][index] = one;
+ fT[1][index] = two;
+ fPt[index] = pt;
+ }
+ return -1;
+ }
+ #if ONE_OFF_DEBUG
+ if (pt.roughlyEqual(fPt[index])) {
+ SkDebugf("%s t=%1.9g pts roughly equal\n", __FUNCTION__, one);
+ }
+ #endif
+ if (fT[0][index] > one) {
+ break;
+ }
+ }
+ SkASSERT(fUsed < 9);
+ int remaining = fUsed - index;
+ if (remaining > 0) {
+ memmove(&fPt[index + 1], &fPt[index], sizeof(fPt[0]) * remaining);
+ memmove(&fT[0][index + 1], &fT[0][index], sizeof(fT[0][0]) * remaining);
+ memmove(&fT[1][index + 1], &fT[1][index], sizeof(fT[1][0]) * remaining);
+ fIsCoincident[0] += fIsCoincident[0] & ~((1 << index) - 1);
+ fIsCoincident[1] += fIsCoincident[1] & ~((1 << index) - 1);
+ }
+ fPt[index] = pt;
+ fT[0][index] = one;
+ fT[1][index] = two;
+ ++fUsed;
+ return index;
+}
+
+void SkIntersections::insertCoincident(double one, double two, const SkDPoint& pt) {
+ int index = insertSwap(one, two, pt);
+ int bit = 1 << index;
+ fIsCoincident[0] |= bit;
+ fIsCoincident[1] |= bit;
+}
+
+void SkIntersections::offset(int base, double start, double end) {
+ for (int index = base; index < fUsed; ++index) {
+ double val = fT[fSwap][index];
+ val *= end - start;
+ val += start;
+ fT[fSwap][index] = val;
+ }
+}
+
+int SkIntersections::quadRay(const SkPoint pts[3], const SkDLine& line) {
+ SkDQuad quad;
+ quad.set(pts);
+ return intersectRay(quad, line);
+}
+
+void SkIntersections::quickRemoveOne(int index, int replace) {
+ if (index < replace) {
+ fT[0][index] = fT[0][replace];
+ }
+}
+
+void SkIntersections::remove(double one, double two, const SkDPoint& startPt,
+ const SkDPoint& endPt) {
+ for (int index = fUsed - 1; index >= 0; --index) {
+ if (!(fIsCoincident[0] & (1 << index)) && (between(one, fT[fSwap][index], two)
+ || startPt.approximatelyEqual(fPt[index])
+ || endPt.approximatelyEqual(fPt[index]))) {
+ SkASSERT(fUsed > 0);
+ removeOne(index);
+ }
+ }
+}
+
+void SkIntersections::removeOne(int index) {
+ int remaining = --fUsed - index;
+ if (remaining <= 0) {
+ return;
+ }
+ memmove(&fPt[index], &fPt[index + 1], sizeof(fPt[0]) * remaining);
+ memmove(&fT[0][index], &fT[0][index + 1], sizeof(fT[0][0]) * remaining);
+ memmove(&fT[1][index], &fT[1][index + 1], sizeof(fT[1][0]) * remaining);
+ SkASSERT(fIsCoincident[0] == 0);
+ int coBit = fIsCoincident[0] & (1 << index);
+ fIsCoincident[0] -= ((fIsCoincident[0] >> 1) & ~((1 << index) - 1)) + coBit;
+ SkASSERT(!(coBit ^ (fIsCoincident[1] & (1 << index))));
+ fIsCoincident[1] -= ((fIsCoincident[1] >> 1) & ~((1 << index) - 1)) + coBit;
+}
+
+void SkIntersections::swapPts() {
+ int index;
+ for (index = 0; index < fUsed; ++index) {
+ SkTSwap(fT[0][index], fT[1][index]);
+ }
+}
+
+int SkIntersections::verticalLine(const SkPoint a[2], SkScalar top, SkScalar bottom,
+ SkScalar x, bool flipped) {
+ SkDLine line;
+ line.set(a);
+ return vertical(line, top, bottom, x, flipped);
+}
+
+int SkIntersections::verticalQuad(const SkPoint a[3], SkScalar top, SkScalar bottom,
+ SkScalar x, bool flipped) {
+ SkDQuad quad;
+ quad.set(a);
+ return vertical(quad, top, bottom, x, flipped);
+}
+
+int SkIntersections::verticalCubic(const SkPoint a[4], SkScalar top, SkScalar bottom,
+ SkScalar x, bool flipped) {
+ SkDCubic cubic;
+ cubic.set(a);
+ return vertical(cubic, top, bottom, x, flipped);
+}