third_party/blink/renderer/platform/geometry/float_quad.cc - chromium/src - Git at Google

 /*
  * Copyright (C) 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2013 Xidorn Quan (quanxunzhen@gmail.com)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
  *     documentation and/or other materials provided with the distribution.
  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  *     its contributors may be used to endorse or promote products derived
  *     from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "third_party/blink/renderer/platform/geometry/float_quad.h"

 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include "third_party/blink/renderer/platform/geometry/float_shape_helpers.h"
 #include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
 #include "third_party/skia/include/core/SkPoint.h"

 namespace blink {

 static inline float Min4(float a, float b, float c, float d) {
   return std::min(std::min(a, b), std::min(c, d));
 }

 static inline float Max4(float a, float b, float c, float d) {
   return std::max(std::max(a, b), std::max(c, d));
 }

 inline float Dot(const FloatSize& a, const FloatSize& b) {
   return a.Width() * b.Width() + a.Height() * b.Height();
 }

 inline bool IsPointInTriangle(const FloatPoint& p,
                               const FloatPoint& t1,
                               const FloatPoint& t2,
                               const FloatPoint& t3) {
   // Compute vectors
   FloatSize v0 = t3 - t1;
   FloatSize v1 = t2 - t1;
   FloatSize v2 = p - t1;

   // Compute dot products
   float dot00 = Dot(v0, v0);
   float dot01 = Dot(v0, v1);
   float dot02 = Dot(v0, v2);
   float dot11 = Dot(v1, v1);
   float dot12 = Dot(v1, v2);

   // Compute barycentric coordinates
   float inv_denom = 1.0f / (dot00 * dot11 - dot01 * dot01);
   float u = (dot11 * dot02 - dot01 * dot12) * inv_denom;
   float v = (dot00 * dot12 - dot01 * dot02) * inv_denom;

   // Check if point is in triangle
   return (u >= 0) && (v >= 0) && (u + v <= 1);
 }

 static inline float SaturateInf(float value) {
   if (UNLIKELY(std::isinf(value))) {
     return std::signbit(value) ? std::numeric_limits<int>::min()
                                : std::numeric_limits<int>::max();
   }
   return value;
 }

 FloatRect FloatQuad::BoundingBox() const {
   float left = SaturateInf(Min4(p1_.X(), p2_.X(), p3_.X(), p4_.X()));
   float top = SaturateInf(Min4(p1_.Y(), p2_.Y(), p3_.Y(), p4_.Y()));

   float right = SaturateInf(Max4(p1_.X(), p2_.X(), p3_.X(), p4_.X()));
   float bottom = SaturateInf(Max4(p1_.Y(), p2_.Y(), p3_.Y(), p4_.Y()));

   return FloatRect(left, top, right - left, bottom - top);
 }

 static inline bool WithinEpsilon(float a, float b) {
   return fabs(a - b) < std::numeric_limits<float>::epsilon();
 }

 FloatQuad::FloatQuad(const SkPoint (&quad)[4])
     : FloatQuad(FloatPoint(quad[0]),
                 FloatPoint(quad[1]),
                 FloatPoint(quad[2]),
                 FloatPoint(quad[3])) {}

 bool FloatQuad::IsRectilinear() const {
   return (WithinEpsilon(p1_.X(), p2_.X()) && WithinEpsilon(p2_.Y(), p3_.Y()) &&
           WithinEpsilon(p3_.X(), p4_.X()) && WithinEpsilon(p4_.Y(), p1_.Y())) ||
          (WithinEpsilon(p1_.Y(), p2_.Y()) && WithinEpsilon(p2_.X(), p3_.X()) &&
           WithinEpsilon(p3_.Y(), p4_.Y()) && WithinEpsilon(p4_.X(), p1_.X()));
 }

 bool FloatQuad::ContainsPoint(const FloatPoint& p) const {
   return IsPointInTriangle(p, p1_, p2_, p3_) ||
          IsPointInTriangle(p, p1_, p3_, p4_);
 }

 // Note that we only handle convex quads here.
 bool FloatQuad::ContainsQuad(const FloatQuad& other) const {
   return ContainsPoint(other.P1()) && ContainsPoint(other.P2()) &&
          ContainsPoint(other.P3()) && ContainsPoint(other.P4());
 }

 static inline FloatPoint RightMostCornerToVector(const FloatRect& rect,
                                                  const FloatSize& vector) {
   // Return the corner of the rectangle that if it is to the left of the vector
   // would mean all of the rectangle is to the left of the vector.
   // The vector here represents the side between two points in a clockwise
   // convex polygon.
   //
   //  Q  XXX
   // QQQ XXX   If the lower left corner of X is left of the vector that goes
   //  QQQ      from the top corner of Q to the right corner of Q, then all of X
   //   Q       is left of the vector, and intersection impossible.
   //
   FloatPoint point;
   if (vector.Width() >= 0)
     point.SetY(rect.MaxY());
   else
     point.SetY(rect.Y());
   if (vector.Height() >= 0)
     point.SetX(rect.X());
   else
     point.SetX(rect.MaxX());
   return point;
 }

 bool FloatQuad::IntersectsRect(const FloatRect& rect) const {
   // IntersectsRect is only valid on convex quads which an empty quad is not.
   DCHECK(!IsEmpty());

   // For each side of the quad clockwise we check if the rectangle is to the
   // left of it since only content on the right can onlap with the quad.  This
   // only works if the quad is convex.
   FloatSize v1, v2, v3, v4;

   // Ensure we use clockwise vectors.
   if (!IsCounterclockwise()) {
     v1 = p2_ - p1_;
     v2 = p3_ - p2_;
     v3 = p4_ - p3_;
     v4 = p1_ - p4_;
   } else {
     v1 = p4_ - p1_;
     v2 = p1_ - p2_;
     v3 = p2_ - p3_;
     v4 = p3_ - p4_;
   }

   FloatPoint p = RightMostCornerToVector(rect, v1);
   if (Determinant(v1, p - p1_) < 0)
     return false;

   p = RightMostCornerToVector(rect, v2);
   if (Determinant(v2, p - p2_) < 0)
     return false;

   p = RightMostCornerToVector(rect, v3);
   if (Determinant(v3, p - p3_) < 0)
     return false;

   p = RightMostCornerToVector(rect, v4);
   if (Determinant(v4, p - p4_) < 0)
     return false;

   // If not all of the rectangle is outside one of the quad's four sides, then
   // that means at least a part of the rectangle is overlapping the quad.
   return true;
 }

 // Tests whether the line is contained by or intersected with the circle.
 static inline bool LineIntersectsCircle(const FloatPoint& center,
                                         float radius,
                                         const FloatPoint& p0,
                                         const FloatPoint& p1) {
   float x0 = p0.X() - center.X(), y0 = p0.Y() - center.Y();
   float x1 = p1.X() - center.X(), y1 = p1.Y() - center.Y();
   float radius2 = radius * radius;
   if ((x0 * x0 + y0 * y0) <= radius2 || (x1 * x1 + y1 * y1) <= radius2)
     return true;
   if (p0 == p1)
     return false;

   float a = y0 - y1;
   float b = x1 - x0;
   float c = x0 * y1 - x1 * y0;
   float distance2 = c * c / (a * a + b * b);
   // If distance between the center point and the line > the radius,
   // the line doesn't cross (or is contained by) the ellipse.
   if (distance2 > radius2)
     return false;

   // The nearest point on the line is between p0 and p1?
   float x = -a * c / (a * a + b * b);
   float y = -b * c / (a * a + b * b);

   return (((x0 <= x && x <= x1) || (x0 >= x && x >= x1)) &&
           ((y0 <= y && y <= y1) || (y1 <= y && y <= y0)));
 }

 bool FloatQuad::IntersectsCircle(const FloatPoint& center, float radius) const {
   return ContainsPoint(
              center)  // The circle may be totally contained by the quad.
          || LineIntersectsCircle(center, radius, p1_, p2_) ||
          LineIntersectsCircle(center, radius, p2_, p3_) ||
          LineIntersectsCircle(center, radius, p3_, p4_) ||
          LineIntersectsCircle(center, radius, p4_, p1_);
 }

 bool FloatQuad::IntersectsEllipse(const FloatPoint& center,
                                   const FloatSize& radii) const {
   // Transform the ellipse to an origin-centered circle whose radius is the
   // product of major radius and minor radius.  Here we apply the same
   // transformation to the quad.
   FloatQuad transformed_quad(*this);
   transformed_quad.Move(-center.X(), -center.Y());
   transformed_quad.Scale(radii.Height(), radii.Width());

   FloatPoint origin_point;
   return transformed_quad.IntersectsCircle(origin_point,
                                            radii.Height() * radii.Width());
 }

 bool FloatQuad::IsCounterclockwise() const {
   // Return if the two first vectors are turning clockwise. If the quad is
   // convex then all following vectors will turn the same way.
   return Determinant(p2_ - p1_, p3_ - p2_) < 0;
 }

 std::ostream& operator<<(std::ostream& ostream, const FloatQuad& quad) {
   return ostream << quad.ToString();
 }

 String FloatQuad::ToString() const {
   return String::Format("%s; %s; %s; %s", p1_.ToString().Ascii().c_str(),
                         p2_.ToString().Ascii().c_str(),
                         p3_.ToString().Ascii().c_str(),
                         p4_.ToString().Ascii().c_str());
 }

 }  // namespace blink
	/*
	* Copyright (C) 2008 Apple Inc. All rights reserved.
	* Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
	* Copyright (C) 2013 Xidorn Quan (quanxunzhen@gmail.com)
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
	* its contributors may be used to endorse or promote products derived
	* from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
	* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
	* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
	* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
	* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "third_party/blink/renderer/platform/geometry/float_quad.h"

	#include <algorithm>
	#include <cmath>
	#include <limits>
	#include "third_party/blink/renderer/platform/geometry/float_shape_helpers.h"
	#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
	#include "third_party/skia/include/core/SkPoint.h"

	namespace blink {

	static inline float Min4(float a, float b, float c, float d) {
	return std::min(std::min(a, b), std::min(c, d));
	}

	static inline float Max4(float a, float b, float c, float d) {
	return std::max(std::max(a, b), std::max(c, d));
	}

	inline float Dot(const FloatSize& a, const FloatSize& b) {
	return a.Width() * b.Width() + a.Height() * b.Height();
	}

	inline bool IsPointInTriangle(const FloatPoint& p,
	const FloatPoint& t1,
	const FloatPoint& t2,
	const FloatPoint& t3) {
	// Compute vectors
	FloatSize v0 = t3 - t1;
	FloatSize v1 = t2 - t1;
	FloatSize v2 = p - t1;

	// Compute dot products
	float dot00 = Dot(v0, v0);
	float dot01 = Dot(v0, v1);
	float dot02 = Dot(v0, v2);
	float dot11 = Dot(v1, v1);
	float dot12 = Dot(v1, v2);

	// Compute barycentric coordinates
	float inv_denom = 1.0f / (dot00 * dot11 - dot01 * dot01);
	float u = (dot11 * dot02 - dot01 * dot12) * inv_denom;
	float v = (dot00 * dot12 - dot01 * dot02) * inv_denom;

	// Check if point is in triangle
	return (u >= 0) && (v >= 0) && (u + v <= 1);
	}

	static inline float SaturateInf(float value) {
	if (UNLIKELY(std::isinf(value))) {
	return std::signbit(value) ? std::numeric_limits<int>::min()
	: std::numeric_limits<int>::max();
	}
	return value;
	}

	FloatRect FloatQuad::BoundingBox() const {
	float left = SaturateInf(Min4(p1_.X(), p2_.X(), p3_.X(), p4_.X()));
	float top = SaturateInf(Min4(p1_.Y(), p2_.Y(), p3_.Y(), p4_.Y()));

	float right = SaturateInf(Max4(p1_.X(), p2_.X(), p3_.X(), p4_.X()));
	float bottom = SaturateInf(Max4(p1_.Y(), p2_.Y(), p3_.Y(), p4_.Y()));

	return FloatRect(left, top, right - left, bottom - top);
	}

	static inline bool WithinEpsilon(float a, float b) {
	return fabs(a - b) < std::numeric_limits<float>::epsilon();
	}

	FloatQuad::FloatQuad(const SkPoint (&quad)[4])
	: FloatQuad(FloatPoint(quad[0]),
	FloatPoint(quad[1]),
	FloatPoint(quad[2]),
	FloatPoint(quad[3])) {}

	bool FloatQuad::IsRectilinear() const {
	return (WithinEpsilon(p1_.X(), p2_.X()) && WithinEpsilon(p2_.Y(), p3_.Y()) &&
	WithinEpsilon(p3_.X(), p4_.X()) && WithinEpsilon(p4_.Y(), p1_.Y())) \|\|
	(WithinEpsilon(p1_.Y(), p2_.Y()) && WithinEpsilon(p2_.X(), p3_.X()) &&
	WithinEpsilon(p3_.Y(), p4_.Y()) && WithinEpsilon(p4_.X(), p1_.X()));
	}

	bool FloatQuad::ContainsPoint(const FloatPoint& p) const {
	return IsPointInTriangle(p, p1_, p2_, p3_) \|\|
	IsPointInTriangle(p, p1_, p3_, p4_);
	}

	// Note that we only handle convex quads here.
	bool FloatQuad::ContainsQuad(const FloatQuad& other) const {
	return ContainsPoint(other.P1()) && ContainsPoint(other.P2()) &&
	ContainsPoint(other.P3()) && ContainsPoint(other.P4());
	}

	static inline FloatPoint RightMostCornerToVector(const FloatRect& rect,
	const FloatSize& vector) {
	// Return the corner of the rectangle that if it is to the left of the vector
	// would mean all of the rectangle is to the left of the vector.
	// The vector here represents the side between two points in a clockwise
	// convex polygon.
	//
	// Q XXX
	// QQQ XXX If the lower left corner of X is left of the vector that goes
	// QQQ from the top corner of Q to the right corner of Q, then all of X
	// Q is left of the vector, and intersection impossible.
	//
	FloatPoint point;
	if (vector.Width() >= 0)
	point.SetY(rect.MaxY());
	else
	point.SetY(rect.Y());
	if (vector.Height() >= 0)
	point.SetX(rect.X());
	else
	point.SetX(rect.MaxX());
	return point;
	}

	bool FloatQuad::IntersectsRect(const FloatRect& rect) const {
	// IntersectsRect is only valid on convex quads which an empty quad is not.
	DCHECK(!IsEmpty());

	// For each side of the quad clockwise we check if the rectangle is to the
	// left of it since only content on the right can onlap with the quad. This
	// only works if the quad is convex.
	FloatSize v1, v2, v3, v4;

	// Ensure we use clockwise vectors.
	if (!IsCounterclockwise()) {
	v1 = p2_ - p1_;
	v2 = p3_ - p2_;
	v3 = p4_ - p3_;
	v4 = p1_ - p4_;
	} else {
	v1 = p4_ - p1_;
	v2 = p1_ - p2_;
	v3 = p2_ - p3_;
	v4 = p3_ - p4_;
	}

	FloatPoint p = RightMostCornerToVector(rect, v1);
	if (Determinant(v1, p - p1_) < 0)
	return false;

	p = RightMostCornerToVector(rect, v2);
	if (Determinant(v2, p - p2_) < 0)
	return false;

	p = RightMostCornerToVector(rect, v3);
	if (Determinant(v3, p - p3_) < 0)
	return false;

	p = RightMostCornerToVector(rect, v4);
	if (Determinant(v4, p - p4_) < 0)
	return false;

	// If not all of the rectangle is outside one of the quad's four sides, then
	// that means at least a part of the rectangle is overlapping the quad.
	return true;
	}

	// Tests whether the line is contained by or intersected with the circle.
	static inline bool LineIntersectsCircle(const FloatPoint& center,
	float radius,
	const FloatPoint& p0,
	const FloatPoint& p1) {
	float x0 = p0.X() - center.X(), y0 = p0.Y() - center.Y();
	float x1 = p1.X() - center.X(), y1 = p1.Y() - center.Y();
	float radius2 = radius * radius;
	if ((x0 * x0 + y0 * y0) <= radius2 \|\| (x1 * x1 + y1 * y1) <= radius2)
	return true;
	if (p0 == p1)
	return false;

	float a = y0 - y1;
	float b = x1 - x0;
	float c = x0 * y1 - x1 * y0;
	float distance2 = c * c / (a * a + b * b);
	// If distance between the center point and the line > the radius,
	// the line doesn't cross (or is contained by) the ellipse.
	if (distance2 > radius2)
	return false;

	// The nearest point on the line is between p0 and p1?
	float x = -a * c / (a * a + b * b);
	float y = -b * c / (a * a + b * b);

	return (((x0 <= x && x <= x1) \|\| (x0 >= x && x >= x1)) &&
	((y0 <= y && y <= y1) \|\| (y1 <= y && y <= y0)));
	}

	bool FloatQuad::IntersectsCircle(const FloatPoint& center, float radius) const {
	return ContainsPoint(
	center) // The circle may be totally contained by the quad.
	\|\| LineIntersectsCircle(center, radius, p1_, p2_) \|\|
	LineIntersectsCircle(center, radius, p2_, p3_) \|\|
	LineIntersectsCircle(center, radius, p3_, p4_) \|\|
	LineIntersectsCircle(center, radius, p4_, p1_);
	}

	bool FloatQuad::IntersectsEllipse(const FloatPoint& center,
	const FloatSize& radii) const {
	// Transform the ellipse to an origin-centered circle whose radius is the
	// product of major radius and minor radius. Here we apply the same
	// transformation to the quad.
	FloatQuad transformed_quad(*this);
	transformed_quad.Move(-center.X(), -center.Y());
	transformed_quad.Scale(radii.Height(), radii.Width());

	FloatPoint origin_point;
	return transformed_quad.IntersectsCircle(origin_point,
	radii.Height() * radii.Width());
	}

	bool FloatQuad::IsCounterclockwise() const {
	// Return if the two first vectors are turning clockwise. If the quad is
	// convex then all following vectors will turn the same way.
	return Determinant(p2_ - p1_, p3_ - p2_) < 0;
	}

	std::ostream& operator<<(std::ostream& ostream, const FloatQuad& quad) {
	return ostream << quad.ToString();
	}

	String FloatQuad::ToString() const {
	return String::Format("%s; %s; %s; %s", p1_.ToString().Ascii().c_str(),
	p2_.ToString().Ascii().c_str(),
	p3_.ToString().Ascii().c_str(),
	p4_.ToString().Ascii().c_str());
	}

	} // namespace blink