GradientCG.cpp   [plain text]

/*
 * Copyright (C) 2006, 2007, 2008 Apple 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 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 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 "Gradient.h"

#if USE(CG)

#include "GraphicsContextCG.h"
#include <CoreGraphics/CoreGraphics.h>
#include <wtf/RetainPtr.h>

namespace WebCore {

void Gradient::platformDestroy()
{
    CGGradientRelease(m_gradient);
    m_gradient = 0;
}

CGGradientRef Gradient::platformGradient()
{
    if (m_gradient)
        return m_gradient;

    sortStopsIfNecessary();

    auto colorsArray = adoptCF(CFArrayCreateMutable(0, m_stops.size(), &kCFTypeArrayCallBacks));
    unsigned numStops = m_stops.size();

    const int reservedStops = 3;
    Vector<CGFloat, reservedStops> locations;
    locations.reserveInitialCapacity(numStops);

    Vector<CGFloat, 4 * reservedStops> colorComponents;
    colorComponents.reserveInitialCapacity(numStops * 4);

    bool hasExtendedColors = false;
    for (const auto& stop : m_stops) {

        // If all the stops are sRGB, it is faster to create a gradient using
        // components than CGColors.
        // FIXME: Rather than just check for extended colors, we should check the actual
        // color space, and whether or not the components are outside [0-1].
        // <rdar://problem/32926606>

        if (stop.color.isExtended())
            hasExtendedColors = true;

        float r;
        float g;
        float b;
        float a;
        stop.color.getRGBA(r, g, b, a);
        colorComponents.uncheckedAppend(r);
        colorComponents.uncheckedAppend(g);
        colorComponents.uncheckedAppend(b);
        colorComponents.uncheckedAppend(a);

        CFArrayAppendValue(colorsArray.get(), cachedCGColor(stop.color));
        locations.uncheckedAppend(stop.offset);
    }

    if (hasExtendedColors)
        m_gradient = CGGradientCreateWithColors(extendedSRGBColorSpaceRef(), colorsArray.get(), locations.data());
    else
        m_gradient = CGGradientCreateWithColorComponents(sRGBColorSpaceRef(), colorComponents.data(), locations.data(), numStops);

    return m_gradient;
}

void Gradient::fill(GraphicsContext* context, const FloatRect& rect)
{
    context->clip(rect);
    paint(context);
}

void Gradient::paint(GraphicsContext* context)
{
    CGContextRef ctx = context->platformContext();
    paint(ctx);
}

void Gradient::paint(CGContextRef context)
{
    CGGradientDrawingOptions extendOptions = kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation;
    if (!m_radial) {
        CGContextDrawLinearGradient(context, platformGradient(), m_p0, m_p1, extendOptions);
        return;
    }

    bool needScaling = aspectRatio() != 1;
    if (needScaling) {
        CGContextSaveGState(context);
        // Scale from the center of the gradient. We only ever scale non-deprecated gradients,
        // for which m_p0 == m_p1.
        ASSERT(m_p0 == m_p1);
        CGContextTranslateCTM(context, m_p0.x(), m_p0.y());
        CGContextScaleCTM(context, 1, 1 / aspectRatio());
        CGContextTranslateCTM(context, -m_p0.x(), -m_p0.y());
    }

    CGContextDrawRadialGradient(context, platformGradient(), m_p0, m_r0, m_p1, m_r1, extendOptions);

    if (needScaling)
        CGContextRestoreGState(context);
}

} //namespace

#endif