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      1 /*
      2  * Copyright (C) 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
      3  * Copyright (C) 2007 Alp Toker <alp (at) atoker.com>
      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 "Gradient.h"
     29 
     30 #include "Color.h"
     31 #include "FloatRect.h"
     32 #include <wtf/UnusedParam.h>
     33 
     34 namespace WebCore {
     35 
     36 Gradient::Gradient(const FloatPoint& p0, const FloatPoint& p1)
     37     : m_radial(false)
     38     , m_p0(p0)
     39     , m_p1(p1)
     40     , m_r0(0)
     41     , m_r1(0)
     42     , m_stopsSorted(false)
     43     , m_lastStop(0)
     44     , m_spreadMethod(SpreadMethodPad)
     45 {
     46     platformInit();
     47 }
     48 
     49 Gradient::Gradient(const FloatPoint& p0, float r0, const FloatPoint& p1, float r1)
     50     : m_radial(true)
     51     , m_p0(p0)
     52     , m_p1(p1)
     53     , m_r0(r0)
     54     , m_r1(r1)
     55     , m_stopsSorted(false)
     56     , m_lastStop(0)
     57     , m_spreadMethod(SpreadMethodPad)
     58 {
     59     platformInit();
     60 }
     61 
     62 Gradient::~Gradient()
     63 {
     64     platformDestroy();
     65 }
     66 
     67 void Gradient::adjustParametersForTiledDrawing(IntSize& size, FloatRect& srcRect)
     68 {
     69     if (m_radial)
     70         return;
     71 
     72     if (srcRect.isEmpty())
     73         return;
     74 
     75     if (m_p0.x() == m_p1.x()) {
     76         size.setWidth(1);
     77         srcRect.setWidth(1);
     78         srcRect.setX(0);
     79         return;
     80     }
     81     if (m_p0.y() != m_p1.y())
     82         return;
     83 
     84     size.setHeight(1);
     85     srcRect.setHeight(1);
     86     srcRect.setY(0);
     87 }
     88 
     89 void Gradient::addColorStop(float value, const Color& color)
     90 {
     91     float r;
     92     float g;
     93     float b;
     94     float a;
     95     color.getRGBA(r, g, b, a);
     96     m_stops.append(ColorStop(value, r, g, b, a));
     97 
     98     m_stopsSorted = false;
     99 
    100     platformDestroy();
    101 }
    102 
    103 static inline bool compareStops(const Gradient::ColorStop& a, const Gradient::ColorStop& b)
    104 {
    105     return a.stop < b.stop;
    106 }
    107 
    108 void Gradient::sortStopsIfNecessary()
    109 {
    110     if (m_stopsSorted)
    111         return;
    112 
    113     if (m_stops.size())
    114         std::stable_sort(m_stops.begin(), m_stops.end(), compareStops);
    115     m_stopsSorted = true;
    116 }
    117 
    118 void Gradient::getColor(float value, float* r, float* g, float* b, float* a) const
    119 {
    120     ASSERT(value >= 0);
    121     ASSERT(value <= 1);
    122 
    123     if (m_stops.isEmpty()) {
    124         *r = 0;
    125         *g = 0;
    126         *b = 0;
    127         *a = 0;
    128         return;
    129     }
    130     if (!m_stopsSorted) {
    131         if (m_stops.size())
    132             std::stable_sort(m_stops.begin(), m_stops.end(), compareStops);
    133         m_stopsSorted = true;
    134     }
    135     if (value <= 0 || value <= m_stops.first().stop) {
    136         *r = m_stops.first().red;
    137         *g = m_stops.first().green;
    138         *b = m_stops.first().blue;
    139         *a = m_stops.first().alpha;
    140         return;
    141     }
    142     if (value >= 1 || value >= m_stops.last().stop) {
    143         *r = m_stops.last().red;
    144         *g = m_stops.last().green;
    145         *b = m_stops.last().blue;
    146         *a = m_stops.last().alpha;
    147         return;
    148     }
    149 
    150     // Find stop before and stop after and interpolate.
    151     int stop = findStop(value);
    152     const ColorStop& lastStop = m_stops[stop];
    153     const ColorStop& nextStop = m_stops[stop + 1];
    154     float stopFraction = (value - lastStop.stop) / (nextStop.stop - lastStop.stop);
    155     *r = lastStop.red + (nextStop.red - lastStop.red) * stopFraction;
    156     *g = lastStop.green + (nextStop.green - lastStop.green) * stopFraction;
    157     *b = lastStop.blue + (nextStop.blue - lastStop.blue) * stopFraction;
    158     *a = lastStop.alpha + (nextStop.alpha - lastStop.alpha) * stopFraction;
    159 }
    160 
    161 int Gradient::findStop(float value) const
    162 {
    163     ASSERT(value >= 0);
    164     ASSERT(value <= 1);
    165     ASSERT(m_stopsSorted);
    166 
    167     int numStops = m_stops.size();
    168     ASSERT(numStops >= 2);
    169     ASSERT(m_lastStop < numStops - 1);
    170 
    171     int i = m_lastStop;
    172     if (value < m_stops[i].stop)
    173         i = 1;
    174     else
    175         i = m_lastStop + 1;
    176 
    177     for (; i < numStops - 1; ++i)
    178         if (value < m_stops[i].stop)
    179             break;
    180 
    181     m_lastStop = i - 1;
    182     return m_lastStop;
    183 }
    184 
    185 void Gradient::setSpreadMethod(GradientSpreadMethod spreadMethod)
    186 {
    187     // FIXME: Should it become necessary, allow calls to this method after m_gradient has been set.
    188     ASSERT(m_gradient == 0);
    189     m_spreadMethod = spreadMethod;
    190 }
    191 
    192 void Gradient::setGradientSpaceTransform(const AffineTransform& gradientSpaceTransformation)
    193 {
    194     m_gradientSpaceTransformation = gradientSpaceTransformation;
    195     setPlatformGradientSpaceTransform(gradientSpaceTransformation);
    196 }
    197 
    198 #if !(PLATFORM(SKIA) && !PLATFORM(ANDROID))
    199 void Gradient::setPlatformGradientSpaceTransform(const AffineTransform&)
    200 {
    201 }
    202 #endif
    203 
    204 
    205 } //namespace
    206