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| 1 /* | |
| 2 * Copyright (C) 2008 Apple Inc. All rights reserved. | |
| 3 * Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies) | |
| 4 * Copyright (C) 2013 Xidorn Quan (quanxunzhen@gmail.com) | |
| 5 * | |
| 6 * Redistribution and use in source and binary forms, with or without | |
| 7 * modification, are permitted provided that the following conditions | |
| 8 * are met: | |
| 9 * | |
| 10 * 1. Redistributions of source code must retain the above copyright | |
| 11 * notice, this list of conditions and the following disclaimer. | |
| 12 * 2. Redistributions in binary form must reproduce the above copyright | |
| 13 * notice, this list of conditions and the following disclaimer in the | |
| 14 * documentation and/or other materials provided with the distribution. | |
| 15 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of | |
| 16 * its contributors may be used to endorse or promote products derived | |
| 17 * from this software without specific prior written permission. | |
| 18 * | |
| 19 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY | |
| 20 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED | |
| 21 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE | |
| 22 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY | |
| 23 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES | |
| 24 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
| 25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND | |
| 26 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
| 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 29 */ | |
| 30 | |
| 31 #include "config.h" | |
| 32 #include "core/platform/graphics/FloatQuad.h" | |
| 33 | |
| 34 #include <algorithm> | |
| 35 #include <limits> | |
| 36 | |
| 37 using namespace std; | |
| 38 | |
| 39 namespace WebCore { | |
| 40 | |
| 41 static inline float min4(float a, float b, float c, float d) | |
| 42 { | |
| 43 return min(min(a, b), min(c, d)); | |
| 44 } | |
| 45 | |
| 46 static inline float max4(float a, float b, float c, float d) | |
| 47 { | |
| 48 return max(max(a, b), max(c, d)); | |
| 49 } | |
| 50 | |
| 51 inline float dot(const FloatSize& a, const FloatSize& b) | |
| 52 { | |
| 53 return a.width() * b.width() + a.height() * b.height(); | |
| 54 } | |
| 55 | |
| 56 inline float determinant(const FloatSize& a, const FloatSize& b) | |
| 57 { | |
| 58 return a.width() * b.height() - a.height() * b.width(); | |
| 59 } | |
| 60 | |
| 61 inline bool isPointInTriangle(const FloatPoint& p, const FloatPoint& t1, const F
loatPoint& t2, const FloatPoint& t3) | |
| 62 { | |
| 63 // Compute vectors | |
| 64 FloatSize v0 = t3 - t1; | |
| 65 FloatSize v1 = t2 - t1; | |
| 66 FloatSize v2 = p - t1; | |
| 67 | |
| 68 // Compute dot products | |
| 69 float dot00 = dot(v0, v0); | |
| 70 float dot01 = dot(v0, v1); | |
| 71 float dot02 = dot(v0, v2); | |
| 72 float dot11 = dot(v1, v1); | |
| 73 float dot12 = dot(v1, v2); | |
| 74 | |
| 75 // Compute barycentric coordinates | |
| 76 float invDenom = 1.0f / (dot00 * dot11 - dot01 * dot01); | |
| 77 float u = (dot11 * dot02 - dot01 * dot12) * invDenom; | |
| 78 float v = (dot00 * dot12 - dot01 * dot02) * invDenom; | |
| 79 | |
| 80 // Check if point is in triangle | |
| 81 return (u >= 0) && (v >= 0) && (u + v <= 1); | |
| 82 } | |
| 83 | |
| 84 FloatRect FloatQuad::boundingBox() const | |
| 85 { | |
| 86 float left = min4(m_p1.x(), m_p2.x(), m_p3.x(), m_p4.x()); | |
| 87 float top = min4(m_p1.y(), m_p2.y(), m_p3.y(), m_p4.y()); | |
| 88 | |
| 89 float right = max4(m_p1.x(), m_p2.x(), m_p3.x(), m_p4.x()); | |
| 90 float bottom = max4(m_p1.y(), m_p2.y(), m_p3.y(), m_p4.y()); | |
| 91 | |
| 92 return FloatRect(left, top, right - left, bottom - top); | |
| 93 } | |
| 94 | |
| 95 static inline bool withinEpsilon(float a, float b) | |
| 96 { | |
| 97 return fabs(a - b) < numeric_limits<float>::epsilon(); | |
| 98 } | |
| 99 | |
| 100 bool FloatQuad::isRectilinear() const | |
| 101 { | |
| 102 return (withinEpsilon(m_p1.x(), m_p2.x()) && withinEpsilon(m_p2.y(), m_p3.y(
)) && withinEpsilon(m_p3.x(), m_p4.x()) && withinEpsilon(m_p4.y(), m_p1.y())) | |
| 103 || (withinEpsilon(m_p1.y(), m_p2.y()) && withinEpsilon(m_p2.x(), m_p3.x(
)) && withinEpsilon(m_p3.y(), m_p4.y()) && withinEpsilon(m_p4.x(), m_p1.x())); | |
| 104 } | |
| 105 | |
| 106 bool FloatQuad::containsPoint(const FloatPoint& p) const | |
| 107 { | |
| 108 return isPointInTriangle(p, m_p1, m_p2, m_p3) || isPointInTriangle(p, m_p1,
m_p3, m_p4); | |
| 109 } | |
| 110 | |
| 111 // Note that we only handle convex quads here. | |
| 112 bool FloatQuad::containsQuad(const FloatQuad& other) const | |
| 113 { | |
| 114 return containsPoint(other.p1()) && containsPoint(other.p2()) && containsPoi
nt(other.p3()) && containsPoint(other.p4()); | |
| 115 } | |
| 116 | |
| 117 static inline FloatPoint rightMostCornerToVector(const FloatRect& rect, const Fl
oatSize& vector) | |
| 118 { | |
| 119 // Return the corner of the rectangle that if it is to the left of the vecto
r | |
| 120 // would mean all of the rectangle is to the left of the vector. | |
| 121 // The vector here represents the side between two points in a clockwise con
vex polygon. | |
| 122 // | |
| 123 // Q XXX | |
| 124 // QQQ XXX If the lower left corner of X is left of the vector that goes f
rom the top corner of Q to | |
| 125 // QQQ the right corner of Q, then all of X is left of the vector, and
intersection impossible. | |
| 126 // Q | |
| 127 // | |
| 128 FloatPoint point; | |
| 129 if (vector.width() >= 0) | |
| 130 point.setY(rect.maxY()); | |
| 131 else | |
| 132 point.setY(rect.y()); | |
| 133 if (vector.height() >= 0) | |
| 134 point.setX(rect.x()); | |
| 135 else | |
| 136 point.setX(rect.maxX()); | |
| 137 return point; | |
| 138 } | |
| 139 | |
| 140 bool FloatQuad::intersectsRect(const FloatRect& rect) const | |
| 141 { | |
| 142 // For each side of the quad clockwise we check if the rectangle is to the l
eft of it | |
| 143 // since only content on the right can onlap with the quad. | |
| 144 // This only works if the quad is convex. | |
| 145 FloatSize v1, v2, v3, v4; | |
| 146 | |
| 147 // Ensure we use clockwise vectors. | |
| 148 if (!isCounterclockwise()) { | |
| 149 v1 = m_p2 - m_p1; | |
| 150 v2 = m_p3 - m_p2; | |
| 151 v3 = m_p4 - m_p3; | |
| 152 v4 = m_p1 - m_p4; | |
| 153 } else { | |
| 154 v1 = m_p4 - m_p1; | |
| 155 v2 = m_p1 - m_p2; | |
| 156 v3 = m_p2 - m_p3; | |
| 157 v4 = m_p3 - m_p4; | |
| 158 } | |
| 159 | |
| 160 FloatPoint p = rightMostCornerToVector(rect, v1); | |
| 161 if (determinant(v1, p - m_p1) < 0) | |
| 162 return false; | |
| 163 | |
| 164 p = rightMostCornerToVector(rect, v2); | |
| 165 if (determinant(v2, p - m_p2) < 0) | |
| 166 return false; | |
| 167 | |
| 168 p = rightMostCornerToVector(rect, v3); | |
| 169 if (determinant(v3, p - m_p3) < 0) | |
| 170 return false; | |
| 171 | |
| 172 p = rightMostCornerToVector(rect, v4); | |
| 173 if (determinant(v4, p - m_p4) < 0) | |
| 174 return false; | |
| 175 | |
| 176 // If not all of the rectangle is outside one of the quad's four sides, then
that means at least | |
| 177 // a part of the rectangle is overlapping the quad. | |
| 178 return true; | |
| 179 } | |
| 180 | |
| 181 // Tests whether the line is contained by or intersected with the circle. | |
| 182 static inline bool lineIntersectsCircle(const FloatPoint& center, float radius,
const FloatPoint& p0, const FloatPoint& p1) | |
| 183 { | |
| 184 float x0 = p0.x() - center.x(), y0 = p0.y() - center.y(); | |
| 185 float x1 = p1.x() - center.x(), y1 = p1.y() - center.y(); | |
| 186 float radius2 = radius * radius; | |
| 187 if ((x0 * x0 + y0 * y0) <= radius2 || (x1 * x1 + y1 * y1) <= radius2) | |
| 188 return true; | |
| 189 if (p0 == p1) | |
| 190 return false; | |
| 191 | |
| 192 float a = y0 - y1; | |
| 193 float b = x1 - x0; | |
| 194 float c = x0 * y1 - x1 * y0; | |
| 195 float distance2 = c * c / (a * a + b * b); | |
| 196 // If distance between the center point and the line > the radius, | |
| 197 // the line doesn't cross (or is contained by) the ellipse. | |
| 198 if (distance2 > radius2) | |
| 199 return false; | |
| 200 | |
| 201 // The nearest point on the line is between p0 and p1? | |
| 202 float x = - a * c / (a * a + b * b); | |
| 203 float y = - b * c / (a * a + b * b); | |
| 204 return (((x0 <= x && x <= x1) || (x0 >= x && x >= x1)) | |
| 205 && ((y0 <= y && y <= y1) || (y1 <= y && y <= y0))); | |
| 206 } | |
| 207 | |
| 208 bool FloatQuad::intersectsCircle(const FloatPoint& center, float radius) const | |
| 209 { | |
| 210 return containsPoint(center) // The circle may be totally contained by the q
uad. | |
| 211 || lineIntersectsCircle(center, radius, m_p1, m_p2) | |
| 212 || lineIntersectsCircle(center, radius, m_p2, m_p3) | |
| 213 || lineIntersectsCircle(center, radius, m_p3, m_p4) | |
| 214 || lineIntersectsCircle(center, radius, m_p4, m_p1); | |
| 215 } | |
| 216 | |
| 217 bool FloatQuad::intersectsEllipse(const FloatPoint& center, const FloatSize& rad
ii) const | |
| 218 { | |
| 219 // Transform the ellipse to an origin-centered circle whose radius is the pr
oduct of major radius and minor radius. | |
| 220 // Here we apply the same transformation to the quad. | |
| 221 FloatQuad transformedQuad(*this); | |
| 222 transformedQuad.move(-center.x(), -center.y()); | |
| 223 transformedQuad.scale(radii.height(), radii.width()); | |
| 224 | |
| 225 FloatPoint originPoint; | |
| 226 return transformedQuad.intersectsCircle(originPoint, radii.height() * radii.
width()); | |
| 227 | |
| 228 } | |
| 229 | |
| 230 bool FloatQuad::isCounterclockwise() const | |
| 231 { | |
| 232 // Return if the two first vectors are turning clockwise. If the quad is con
vex then all following vectors will turn the same way. | |
| 233 return determinant(m_p2 - m_p1, m_p3 - m_p2) < 0; | |
| 234 } | |
| 235 | |
| 236 } // namespace WebCore | |
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Chromium Code Reviews
Issue 25494003:
Move geometry classes from core/platform/graphics to platform/geometry (Closed)
Base URL: svn://svn.chromium.org/blink/trunk