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      1 /*
      2  * Copyright (C) 2006, 2007, 2008 Apple Computer, 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 "CSSParser.h"
     31 #include "GraphicsContext.h"
     32 
     33 #include <QGradient>
     34 #include <QPainter>
     35 
     36 namespace WebCore {
     37 
     38 void Gradient::platformDestroy()
     39 {
     40     delete m_gradient;
     41     m_gradient = 0;
     42 }
     43 
     44 QGradient* Gradient::platformGradient()
     45 {
     46     if (m_gradient)
     47         return m_gradient;
     48 
     49     bool reversed = m_r0 > m_r1;
     50 
     51     qreal innerRadius = reversed ? m_r1 : m_r0;
     52     qreal outerRadius = reversed ? m_r0 : m_r1;
     53     QPointF center = reversed ? m_p0 : m_p1;
     54     QPointF focalPoint = reversed ? m_p1 : m_p0;
     55 
     56     if (m_radial)
     57         m_gradient = new QRadialGradient(center, outerRadius, focalPoint);
     58     else
     59         m_gradient = new QLinearGradient(m_p0.x(), m_p0.y(), m_p1.x(), m_p1.y());
     60 
     61     m_gradient->setInterpolationMode(QGradient::ComponentInterpolation);
     62 
     63     sortStopsIfNecessary();
     64 
     65     QColor stopColor;
     66     Vector<ColorStop>::iterator stopIterator = m_stops.begin();
     67     qreal lastStop(0.0);
     68     const qreal lastStopDiff = 0.0000001;
     69     while (stopIterator != m_stops.end()) {
     70         stopColor.setRgbF(stopIterator->red, stopIterator->green, stopIterator->blue, stopIterator->alpha);
     71         if (qFuzzyCompare(lastStop, qreal(stopIterator->stop)))
     72             lastStop = stopIterator->stop + lastStopDiff;
     73         else
     74             lastStop = stopIterator->stop;
     75 
     76         if (m_radial && !qFuzzyCompare(1 + outerRadius, qreal(1))) {
     77             lastStop = lastStop * (1.0f - innerRadius / outerRadius);
     78             if (!reversed)
     79                 lastStop += innerRadius / outerRadius;
     80         }
     81 
     82         qreal stopPosition = qMin(lastStop, qreal(1.0f));
     83 
     84         if (m_radial && reversed)
     85             stopPosition = 1 - stopPosition;
     86 
     87         m_gradient->setColorAt(stopPosition, stopColor);
     88         // Keep the lastStop as orginal value, since the following stopColor depend it
     89         lastStop = stopIterator->stop;
     90         ++stopIterator;
     91     }
     92 
     93     if (m_stops.isEmpty()) {
     94         // The behavior of QGradient with no stops is defined differently from HTML5 spec,
     95         // where the latter requires the gradient to be transparent black.
     96         m_gradient->setColorAt(0.0, QColor(0, 0, 0, 0));
     97     }
     98 
     99     switch (m_spreadMethod) {
    100     case SpreadMethodPad:
    101         m_gradient->setSpread(QGradient::PadSpread);
    102         break;
    103     case SpreadMethodReflect:
    104         m_gradient->setSpread(QGradient::ReflectSpread);
    105         break;
    106     case SpreadMethodRepeat:
    107         m_gradient->setSpread(QGradient::RepeatSpread);
    108         break;
    109     }
    110 
    111     return m_gradient;
    112 }
    113 
    114 void Gradient::fill(GraphicsContext* context, const FloatRect& rect)
    115 {
    116     context->platformContext()->fillRect(rect, *platformGradient());
    117 }
    118 
    119 } //namespace
    120