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      1 /*
      2  * Copyright (C) 2004, 2006, 2007 Apple Inc.  All rights reserved.
      3  * Copyright (C) 2005 Nokia.  All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      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  *
     14  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     15  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     17  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     18  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     19  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     20  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     21  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     22  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 #include "config.h"
     28 #include "platform/geometry/FloatPoint.h"
     29 
     30 #include "SkPoint.h"
     31 #include "platform/FloatConversion.h"
     32 #include "platform/geometry/LayoutPoint.h"
     33 #include "platform/geometry/LayoutSize.h"
     34 #include <limits>
     35 #include <math.h>
     36 
     37 namespace WebCore {
     38 
     39 // Skia has problems when passed infinite, etc floats, filter them to 0.
     40 static inline SkScalar WebCoreFloatToSkScalar(float f)
     41 {
     42     return SkFloatToScalar(std::isfinite(f) ? f : 0);
     43 }
     44 
     45 FloatPoint::FloatPoint(const IntPoint& p) : m_x(p.x()), m_y(p.y())
     46 {
     47 }
     48 
     49 FloatPoint::FloatPoint(const LayoutPoint& p)
     50     : m_x(p.x().toFloat())
     51     , m_y(p.y().toFloat())
     52 {
     53 }
     54 
     55 void FloatPoint::normalize()
     56 {
     57     float tempLength = length();
     58 
     59     if (tempLength) {
     60         m_x /= tempLength;
     61         m_y /= tempLength;
     62     }
     63 }
     64 
     65 float FloatPoint::slopeAngleRadians() const
     66 {
     67     return atan2f(m_y, m_x);
     68 }
     69 
     70 float FloatPoint::length() const
     71 {
     72     return sqrtf(lengthSquared());
     73 }
     74 
     75 void FloatPoint::move(const LayoutSize& size)
     76 {
     77     m_x += size.width();
     78     m_y += size.height();
     79 }
     80 
     81 void FloatPoint::moveBy(const LayoutPoint& point)
     82 {
     83     m_x += point.x();
     84     m_y += point.y();
     85 }
     86 
     87 SkPoint FloatPoint::data() const
     88 {
     89     SkPoint p = { WebCoreFloatToSkScalar(m_x), WebCoreFloatToSkScalar(m_y) };
     90     return p;
     91 }
     92 
     93 FloatPoint FloatPoint::narrowPrecision(double x, double y)
     94 {
     95     return FloatPoint(narrowPrecisionToFloat(x), narrowPrecisionToFloat(y));
     96 }
     97 
     98 float findSlope(const FloatPoint& p1, const FloatPoint& p2, float& c)
     99 {
    100     if (p2.x() == p1.x())
    101         return std::numeric_limits<float>::infinity();
    102 
    103     // y = mx + c
    104     float slope = (p2.y() - p1.y()) / (p2.x() - p1.x());
    105     c = p1.y() - slope * p1.x();
    106     return slope;
    107 }
    108 
    109 bool findIntersection(const FloatPoint& p1, const FloatPoint& p2, const FloatPoint& d1, const FloatPoint& d2, FloatPoint& intersection)
    110 {
    111     float pxLength = p2.x() - p1.x();
    112     float pyLength = p2.y() - p1.y();
    113 
    114     float dxLength = d2.x() - d1.x();
    115     float dyLength = d2.y() - d1.y();
    116 
    117     float denom = pxLength * dyLength - pyLength * dxLength;
    118     if (!denom)
    119         return false;
    120 
    121     float param = ((d1.x() - p1.x()) * dyLength - (d1.y() - p1.y()) * dxLength) / denom;
    122 
    123     intersection.setX(p1.x() + param * pxLength);
    124     intersection.setY(p1.y() + param * pyLength);
    125     return true;
    126 }
    127 
    128 }
    129