/*

 * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.

 * Copyright (C) 2007 Alp Toker <alp@atoker.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.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``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 COMPUTER, INC. OR

 * 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 "config.h"

#include "CanvasGradient.h"

#if PLATFORM(CG)

#include <ApplicationServices/ApplicationServices.h>

#elif PLATFORM(QT)

#include <QGradient>

#elif PLATFORM(CAIRO)

#include <cairo.h>

#endif

namespace WebCore {

CanvasGradient::CanvasGradient(const FloatPoint& p0, const FloatPoint& p1)

    : m_radial(false), m_p0(p0), m_p1(p1), m_stopsSorted(false), m_lastStop(0)

#if PLATFORM(CG)

    , m_shading(0)

#elif PLATFORM(QT)

    , m_shading(0)

#elif PLATFORM(CAIRO)

    , m_shading(0)

#endif

{

}

CanvasGradient::CanvasGradient(const FloatPoint& p0, float r0, const FloatPoint& p1, float r1)

    : m_radial(true), m_p0(p0), m_p1(p1), m_r0(r0), m_r1(r1), m_stopsSorted(false), m_lastStop(0)

#if PLATFORM(CG)

    , m_shading(0)

#elif PLATFORM(QT)

    , m_shading(0)

#elif PLATFORM(CAIRO)

    , m_shading(0)

#endif

{

}

CanvasGradient::~CanvasGradient()

{

#if PLATFORM(CG)

    CGShadingRelease(m_shading);

#elif PLATFORM(QT)

    delete m_shading;

#elif PLATFORM(CAIRO)

    cairo_pattern_destroy(m_shading);

#endif

}

void CanvasGradient::addColorStop(float value, const String& color)

{

    RGBA32 rgba = CSSParser::parseColor(color);

    m_stops.append(ColorStop(value,

        ((rgba >> 16) & 0xFF) / 255.0f,

        ((rgba >> 8) & 0xFF) / 255.0f,

        (rgba & 0xFF) / 255.0f,

        ((rgba >> 24) & 0xFF) / 255.0f));

    m_stopsSorted = false;

#if PLATFORM(CG)

    CGShadingRelease(m_shading);

    m_shading = 0;

#elif PLATFORM(QT)

    delete m_shading;

    m_shading = 0;

#elif PLATFORM(CAIRO)

    cairo_pattern_destroy(m_shading);

    m_shading = 0;

#endif

}

#if PLATFORM(CG)

static void gradientCallback(void* info, const CGFloat* in, CGFloat* out)

{

    float r, g, b, a;

    static_cast<CanvasGradient*>(info)->getColor(*in, &r, &g, &b, &a);

    out[0] = r;

    out[1] = g;

    out[2] = b;

    out[3] = a;

}

CGShadingRef CanvasGradient::platformShading()

{

    if (m_shading)

        return m_shading;

    const CGFloat intervalRanges[2] = { 0, 1 };

    const CGFloat colorComponentRanges[4 * 2] = { 0, 1, 0, 1, 0, 1, 0, 1 };

    const CGFunctionCallbacks gradientCallbacks = { 0, gradientCallback, 0 };

    CGFunctionRef colorFunction = CGFunctionCreate(this, 1, intervalRanges, 4, colorComponentRanges, &gradientCallbacks);

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    if (m_radial)

        m_shading = CGShadingCreateRadial(colorSpace, m_p0, m_r0, m_p1, m_r1, colorFunction, true, true);

    else

        m_shading = CGShadingCreateAxial(colorSpace, m_p0, m_p1, colorFunction, true, true);

    CGColorSpaceRelease(colorSpace);

    CGFunctionRelease(colorFunction);

    return m_shading;

}

#elif PLATFORM(QT)

QGradient* CanvasGradient::platformShading()

{

    if (m_shading)

        return m_shading;

    if (m_radial)

        m_shading = new QRadialGradient(m_p0.x(), m_p0.y(), m_r0, m_p1.x(), m_p1.y());

    else m_shading = new QLinearGradient(m_p0.x(), m_p0.y(), m_p1.x(), m_p1.y());

    QColor stopColor;

    Vector<ColorStop>::iterator stopIterator = m_stops.begin();;

    while (stopIterator != m_stops.end()) {

        stopColor.setRgbF(stopIterator->red, stopIterator->green, stopIterator->blue, stopIterator->alpha);

        m_shading->setColorAt(stopIterator->stop, stopColor);

        ++stopIterator;

    }

    return m_shading;

}

#elif PLATFORM(CAIRO)

cairo_pattern_t* CanvasGradient::platformShading()

{

    if (m_shading)

        return m_shading;

    if (m_radial)

        m_shading = cairo_pattern_create_radial(m_p0.x(), m_p0.y(), m_r0, m_p1.x(), m_p1.y(), m_r1);

    else

        m_shading = cairo_pattern_create_linear(m_p0.x(), m_p0.y(), m_p1.x(), m_p1.y());

    Vector<ColorStop>::iterator stopIterator = m_stops.begin();

    while (stopIterator != m_stops.end()) {

        cairo_pattern_add_color_stop_rgba(m_shading, stopIterator->stop, stopIterator->red, stopIterator->green, stopIterator->blue, stopIterator->alpha);

        ++stopIterator;

    }

    return m_shading;

}

#endif

static inline bool compareStops(const CanvasGradient::ColorStop &a, const CanvasGradient::ColorStop &b)

{

    return a.stop < b.stop;

}

void CanvasGradient::getColor(float value, float* r, float* g, float* b, float* a)

{

    ASSERT(value >= 0);

    ASSERT(value <= 1);

    if (m_stops.isEmpty()) {

        *r = 0;

        *g = 0;

        *b = 0;

        *a = 0;

        return;

    }

    if (!m_stopsSorted) {

        if (m_stops.size())

            std::stable_sort(m_stops.begin(), m_stops.end(), compareStops);

        m_stopsSorted = true;

    }

    if (value <= 0 || value <= m_stops.first().stop) {

        *r = m_stops.first().red;

        *g = m_stops.first().green;

        *b = m_stops.first().blue;

        *a = m_stops.first().alpha;

        return;

    }

    if (value >= 1 || value >= m_stops.last().stop) {

        *r = m_stops.last().red;

        *g = m_stops.last().green;

        *b = m_stops.last().blue;

        *a = m_stops.last().alpha;

        return;

    }

    // Find stop before and stop after and interpolate.

    int stop = findStop(value);

    const ColorStop& lastStop = m_stops[stop];    

    const ColorStop& nextStop = m_stops[stop + 1];

    float stopFraction = (value - lastStop.stop) / (nextStop.stop - lastStop.stop);

    *r = lastStop.red + (nextStop.red - lastStop.red) * stopFraction;

    *g = lastStop.green + (nextStop.green - lastStop.green) * stopFraction;

    *b = lastStop.blue + (nextStop.blue - lastStop.blue) * stopFraction;

    *a = lastStop.alpha + (nextStop.alpha - lastStop.alpha) * stopFraction;

}

int CanvasGradient::findStop(float value) const

{

    ASSERT(value >= 0);

    ASSERT(value <= 1);

    ASSERT(m_stopsSorted);

    int numStops = m_stops.size();

    ASSERT(numStops >= 2);

    ASSERT(m_lastStop < numStops - 1);

    int i = m_lastStop;

    if (value < m_stops[i].stop)

        i = 1;

    else

        i = m_lastStop + 1;

    for (; i < numStops - 1; ++i)

        if (value < m_stops[i].stop)

            break;

    m_lastStop = i - 1;

    return m_lastStop;

}

} //namespace