1 /*
2 * Copyright 2015 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7 #include "src/pathops/SkPathOpsBounds.h"
8 #include "src/pathops/SkPathOpsCurve.h"
9 #include "src/pathops/SkPathOpsRect.h"
10
11 // this cheats and assumes that the perpendicular to the point is the closest ray to the curve
12 // this case (where the line and the curve are nearly coincident) may be the only case that counts
nearPoint(SkPath::Verb verb,const SkDPoint & xy,const SkDPoint & opp) const13 double SkDCurve::nearPoint(SkPath::Verb verb, const SkDPoint& xy, const SkDPoint& opp) const {
14 int count = SkPathOpsVerbToPoints(verb);
15 double minX = fCubic.fPts[0].fX;
16 double maxX = minX;
17 for (int index = 1; index <= count; ++index) {
18 minX = std::min(minX, fCubic.fPts[index].fX);
19 maxX = std::max(maxX, fCubic.fPts[index].fX);
20 }
21 if (!AlmostBetweenUlps(minX, xy.fX, maxX)) {
22 return -1;
23 }
24 double minY = fCubic.fPts[0].fY;
25 double maxY = minY;
26 for (int index = 1; index <= count; ++index) {
27 minY = std::min(minY, fCubic.fPts[index].fY);
28 maxY = std::max(maxY, fCubic.fPts[index].fY);
29 }
30 if (!AlmostBetweenUlps(minY, xy.fY, maxY)) {
31 return -1;
32 }
33 SkIntersections i;
34 SkDLine perp = {{ xy, { xy.fX + opp.fY - xy.fY, xy.fY + xy.fX - opp.fX }}};
35 (*CurveDIntersectRay[verb])(*this, perp, &i);
36 int minIndex = -1;
37 double minDist = FLT_MAX;
38 for (int index = 0; index < i.used(); ++index) {
39 double dist = xy.distance(i.pt(index));
40 if (minDist > dist) {
41 minDist = dist;
42 minIndex = index;
43 }
44 }
45 if (minIndex < 0) {
46 return -1;
47 }
48 double largest = std::max(std::max(maxX, maxY), -std::min(minX, minY));
49 if (!AlmostEqualUlps_Pin(largest, largest + minDist)) { // is distance within ULPS tolerance?
50 return -1;
51 }
52 return SkPinT(i[0][minIndex]);
53 }
54
offset(SkPath::Verb verb,const SkDVector & off)55 void SkDCurve::offset(SkPath::Verb verb, const SkDVector& off) {
56 int count = SkPathOpsVerbToPoints(verb);
57 for (int index = 0; index <= count; ++index) {
58 fCubic.fPts[index] += off;
59 }
60 }
61
setConicBounds(const SkPoint curve[3],SkScalar curveWeight,double tStart,double tEnd,SkPathOpsBounds * bounds)62 void SkDCurve::setConicBounds(const SkPoint curve[3], SkScalar curveWeight,
63 double tStart, double tEnd, SkPathOpsBounds* bounds) {
64 SkDConic dCurve;
65 dCurve.set(curve, curveWeight);
66 SkDRect dRect;
67 dRect.setBounds(dCurve, fConic, tStart, tEnd);
68 bounds->setLTRB(SkDoubleToScalar(dRect.fLeft), SkDoubleToScalar(dRect.fTop),
69 SkDoubleToScalar(dRect.fRight), SkDoubleToScalar(dRect.fBottom));
70 }
71
setCubicBounds(const SkPoint curve[4],SkScalar,double tStart,double tEnd,SkPathOpsBounds * bounds)72 void SkDCurve::setCubicBounds(const SkPoint curve[4], SkScalar ,
73 double tStart, double tEnd, SkPathOpsBounds* bounds) {
74 SkDCubic dCurve;
75 dCurve.set(curve);
76 SkDRect dRect;
77 dRect.setBounds(dCurve, fCubic, tStart, tEnd);
78 bounds->setLTRB(SkDoubleToScalar(dRect.fLeft), SkDoubleToScalar(dRect.fTop),
79 SkDoubleToScalar(dRect.fRight), SkDoubleToScalar(dRect.fBottom));
80 }
81
setQuadBounds(const SkPoint curve[3],SkScalar,double tStart,double tEnd,SkPathOpsBounds * bounds)82 void SkDCurve::setQuadBounds(const SkPoint curve[3], SkScalar ,
83 double tStart, double tEnd, SkPathOpsBounds* bounds) {
84 SkDQuad dCurve;
85 dCurve.set(curve);
86 SkDRect dRect;
87 dRect.setBounds(dCurve, fQuad, tStart, tEnd);
88 bounds->setLTRB(SkDoubleToScalar(dRect.fLeft), SkDoubleToScalar(dRect.fTop),
89 SkDoubleToScalar(dRect.fRight), SkDoubleToScalar(dRect.fBottom));
90 }
91
setCurveHullSweep(SkPath::Verb verb)92 void SkDCurveSweep::setCurveHullSweep(SkPath::Verb verb) {
93 fOrdered = true;
94 fSweep[0] = fCurve[1] - fCurve[0];
95 if (SkPath::kLine_Verb == verb) {
96 fSweep[1] = fSweep[0];
97 fIsCurve = false;
98 return;
99 }
100 fSweep[1] = fCurve[2] - fCurve[0];
101 // OPTIMIZE: I do the following float check a lot -- probably need a
102 // central place for this val-is-small-compared-to-curve check
103 double maxVal = 0;
104 for (int index = 0; index <= SkPathOpsVerbToPoints(verb); ++index) {
105 maxVal = std::max(maxVal, std::max(SkTAbs(fCurve[index].fX),
106 SkTAbs(fCurve[index].fY)));
107 }
108 {
109 if (SkPath::kCubic_Verb != verb) {
110 if (roughly_zero_when_compared_to(fSweep[0].fX, maxVal)
111 && roughly_zero_when_compared_to(fSweep[0].fY, maxVal)) {
112 fSweep[0] = fSweep[1];
113 }
114 goto setIsCurve;
115 }
116 SkDVector thirdSweep = fCurve[3] - fCurve[0];
117 if (fSweep[0].fX == 0 && fSweep[0].fY == 0) {
118 fSweep[0] = fSweep[1];
119 fSweep[1] = thirdSweep;
120 if (roughly_zero_when_compared_to(fSweep[0].fX, maxVal)
121 && roughly_zero_when_compared_to(fSweep[0].fY, maxVal)) {
122 fSweep[0] = fSweep[1];
123 fCurve[1] = fCurve[3];
124 }
125 goto setIsCurve;
126 }
127 double s1x3 = fSweep[0].crossCheck(thirdSweep);
128 double s3x2 = thirdSweep.crossCheck(fSweep[1]);
129 if (s1x3 * s3x2 >= 0) { // if third vector is on or between first two vectors
130 goto setIsCurve;
131 }
132 double s2x1 = fSweep[1].crossCheck(fSweep[0]);
133 // FIXME: If the sweep of the cubic is greater than 180 degrees, we're in trouble
134 // probably such wide sweeps should be artificially subdivided earlier so that never happens
135 SkASSERT(s1x3 * s2x1 < 0 || s1x3 * s3x2 < 0);
136 if (s3x2 * s2x1 < 0) {
137 SkASSERT(s2x1 * s1x3 > 0);
138 fSweep[0] = fSweep[1];
139 fOrdered = false;
140 }
141 fSweep[1] = thirdSweep;
142 }
143 setIsCurve:
144 fIsCurve = fSweep[0].crossCheck(fSweep[1]) != 0;
145 }
146