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      1 /*
      2  * Copyright (C) 2008 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  *
      8  * 1.  Redistributions of source code must retain the above copyright
      9  *     notice, this list of conditions and the following disclaimer.
     10  * 2.  Redistributions in binary form must reproduce the above copyright
     11  *     notice, this list of conditions and the following disclaimer in the
     12  *     documentation and/or other materials provided with the distribution.
     13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
     14  *     its contributors may be used to endorse or promote products derived
     15  *     from this software without specific prior written permission.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
     18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #ifndef FloatQuad_h
     30 #define FloatQuad_h
     31 
     32 #include "core/platform/graphics/FloatPoint.h"
     33 #include "core/platform/graphics/FloatRect.h"
     34 #include "core/platform/graphics/IntRect.h"
     35 
     36 namespace WebCore {
     37 
     38 // A FloatQuad is a collection of 4 points, often representing the result of
     39 // mapping a rectangle through transforms. When initialized from a rect, the
     40 // points are in clockwise order from top left.
     41 class FloatQuad {
     42 public:
     43     FloatQuad()
     44     {
     45     }
     46 
     47     FloatQuad(const FloatPoint& p1, const FloatPoint& p2, const FloatPoint& p3, const FloatPoint& p4)
     48         : m_p1(p1)
     49         , m_p2(p2)
     50         , m_p3(p3)
     51         , m_p4(p4)
     52     {
     53     }
     54 
     55     FloatQuad(const FloatRect& inRect)
     56         : m_p1(inRect.location())
     57         , m_p2(inRect.maxX(), inRect.y())
     58         , m_p3(inRect.maxX(), inRect.maxY())
     59         , m_p4(inRect.x(), inRect.maxY())
     60     {
     61     }
     62 
     63     FloatPoint p1() const { return m_p1; }
     64     FloatPoint p2() const { return m_p2; }
     65     FloatPoint p3() const { return m_p3; }
     66     FloatPoint p4() const { return m_p4; }
     67 
     68     void setP1(const FloatPoint& p) { m_p1 = p; }
     69     void setP2(const FloatPoint& p) { m_p2 = p; }
     70     void setP3(const FloatPoint& p) { m_p3 = p; }
     71     void setP4(const FloatPoint& p) { m_p4 = p; }
     72 
     73     // isEmpty tests that the bounding box is empty. This will not identify
     74     // "slanted" empty quads.
     75     bool isEmpty() const { return boundingBox().isEmpty(); }
     76 
     77     // Tests whether this quad can be losslessly represented by a FloatRect,
     78     // that is, if two edges are parallel to the x-axis and the other two
     79     // are parallel to the y-axis. If this method returns true, the
     80     // corresponding FloatRect can be retrieved with boundingBox().
     81     bool isRectilinear() const;
     82 
     83     // Tests whether the given point is inside, or on an edge or corner of this quad.
     84     bool containsPoint(const FloatPoint&) const;
     85 
     86     // Tests whether the four corners of other are inside, or coincident with the sides of this quad.
     87     // Note that this only works for convex quads, but that includes all quads that originate
     88     // from transformed rects.
     89     bool containsQuad(const FloatQuad&) const;
     90 
     91     // Tests whether any part of the rectangle intersects with this quad.
     92     // This only works for convex quads.
     93     bool intersectsRect(const FloatRect&) const;
     94 
     95     // Test whether any part of the circle/ellipse intersects with this quad.
     96     // Note that these two functions only work for convex quads.
     97     bool intersectsCircle(const FloatPoint& center, float radius) const;
     98     bool intersectsEllipse(const FloatPoint& center, const FloatSize& radii) const;
     99 
    100     // The center of the quad. If the quad is the result of a affine-transformed rectangle this is the same as the original center transformed.
    101     FloatPoint center() const
    102     {
    103         return FloatPoint((m_p1.x() + m_p2.x() + m_p3.x() + m_p4.x()) / 4.0,
    104                           (m_p1.y() + m_p2.y() + m_p3.y() + m_p4.y()) / 4.0);
    105     }
    106 
    107     FloatRect boundingBox() const;
    108     IntRect enclosingBoundingBox() const
    109     {
    110         return enclosingIntRect(boundingBox());
    111     }
    112 
    113     void move(const FloatSize& offset)
    114     {
    115         m_p1 += offset;
    116         m_p2 += offset;
    117         m_p3 += offset;
    118         m_p4 += offset;
    119     }
    120 
    121     void move(float dx, float dy)
    122     {
    123         m_p1.move(dx, dy);
    124         m_p2.move(dx, dy);
    125         m_p3.move(dx, dy);
    126         m_p4.move(dx, dy);
    127     }
    128 
    129     void scale(float dx, float dy)
    130     {
    131         m_p1.scale(dx, dy);
    132         m_p2.scale(dx, dy);
    133         m_p3.scale(dx, dy);
    134         m_p4.scale(dx, dy);
    135     }
    136 
    137     // Tests whether points are in clock-wise, or counter clock-wise order.
    138     // Note that output is undefined when all points are colinear.
    139     bool isCounterclockwise() const;
    140 
    141 private:
    142     FloatPoint m_p1;
    143     FloatPoint m_p2;
    144     FloatPoint m_p3;
    145     FloatPoint m_p4;
    146 };
    147 
    148 inline FloatQuad& operator+=(FloatQuad& a, const FloatSize& b)
    149 {
    150     a.move(b);
    151     return a;
    152 }
    153 
    154 inline FloatQuad& operator-=(FloatQuad& a, const FloatSize& b)
    155 {
    156     a.move(-b.width(), -b.height());
    157     return a;
    158 }
    159 
    160 inline bool operator==(const FloatQuad& a, const FloatQuad& b)
    161 {
    162     return a.p1() == b.p1() &&
    163            a.p2() == b.p2() &&
    164            a.p3() == b.p3() &&
    165            a.p4() == b.p4();
    166 }
    167 
    168 inline bool operator!=(const FloatQuad& a, const FloatQuad& b)
    169 {
    170     return a.p1() != b.p1() ||
    171            a.p2() != b.p2() ||
    172            a.p3() != b.p3() ||
    173            a.p4() != b.p4();
    174 }
    175 
    176 }   // namespace WebCore
    177 
    178 
    179 #endif // FloatQuad_h
    180 
    181