graphicscontextqt.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

/*
 * Copyright (C) 2006 Dirk Mueller <[e-mail]>
 * Copyright (C) 2006 Zack Rusin <[e-mail]>
 * Copyright (C) 2006 George Staikos <[e-mail]>
 * Copyright (C) 2006 Simon Hausmann <[e-mail]>
 * Copyright (C) 2006 Allan Sandfeld Jensen <[e-mail]>
 * Copyright (C) 2006 Nikolas Zimmermann <[e-mail]>
 * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies).
 * Copyright (C) 2008 Dirk Schulze <[e-mail]>
 *
 * All rights reserved.
 *
 * 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"

#ifdef Q_WS_WIN
#include <windows.h>
#endif

#include "TransformationMatrix.h"
#include "Color.h"
#include "FloatConversion.h"
#include "Font.h"
#include "GraphicsContext.h"
#include "GraphicsContextPrivate.h"
#include "ImageBuffer.h"
#include "Path.h"
#include "Pattern.h"
#include "Pen.h"
#include "NotImplemented.h"

#include <QDebug>
#include <QGradient>
#include <QPainter>
#include <QPaintDevice>
#include <QPaintEngine>
#include <QPainterPath>
#include <QPixmap>
#include <QPolygonF>
#include <QStack>
#include <QVector>

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

namespace WebCore {

static inline QPainter::CompositionMode toQtCompositionMode(CompositeOperator op)
{
    switch (op) {
        case CompositeClear:
            return QPainter::CompositionMode_Clear;
        case CompositeCopy:
            return QPainter::CompositionMode_Source;
        case CompositeSourceOver:
            return QPainter::CompositionMode_SourceOver;
        case CompositeSourceIn:
            return QPainter::CompositionMode_SourceIn;
        case CompositeSourceOut:
            return QPainter::CompositionMode_SourceOut;
        case CompositeSourceAtop:
            return QPainter::CompositionMode_SourceAtop;
        case CompositeDestinationOver:
            return QPainter::CompositionMode_DestinationOver;
        case CompositeDestinationIn:
            return QPainter::CompositionMode_DestinationIn;
        case CompositeDestinationOut:
            return QPainter::CompositionMode_DestinationOut;
        case CompositeDestinationAtop:
            return QPainter::CompositionMode_DestinationAtop;
        case CompositeXOR:
            return QPainter::CompositionMode_Xor;
        case CompositePlusDarker:
            return QPainter::CompositionMode_SourceOver;
        case CompositeHighlight:
            return QPainter::CompositionMode_SourceOver;
        case CompositePlusLighter:
            return QPainter::CompositionMode_SourceOver;
    }

    return QPainter::CompositionMode_SourceOver;
}

static inline Qt::PenCapStyle toQtLineCap(LineCap lc)
{
    switch (lc) {
        case ButtCap:
            return Qt::FlatCap;
        case RoundCap:
            return Qt::RoundCap;
        case SquareCap:
            return Qt::SquareCap;
    }

    return Qt::FlatCap;
}

static inline Qt::PenJoinStyle toQtLineJoin(LineJoin lj)
{
    switch (lj) {
        case MiterJoin:
            return Qt::SvgMiterJoin;
        case RoundJoin:
            return Qt::RoundJoin;
        case BevelJoin:
            return Qt::BevelJoin;
    }

    return Qt::MiterJoin;
}

static Qt::PenStyle toQPenStyle(StrokeStyle style)
{
    switch (style) {
    case NoStroke:
        return Qt::NoPen;
        break;
    case SolidStroke:
        return Qt::SolidLine;
        break;
    case DottedStroke:
        return Qt::DotLine;
        break;
    case DashedStroke:
        return Qt::DashLine;
        break;
    }
    qWarning("couldn't recognize the pen style");
    return Qt::NoPen;
}

struct TransparencyLayer
{
    TransparencyLayer(const QPainter* p, const QRect &rect)
        : pixmap(rect.width(), rect.height())
    {
        offset = rect.topLeft();
        pixmap.fill(Qt::transparent);
        painter.begin(&pixmap);
        painter.setRenderHint(QPainter::Antialiasing, p->testRenderHint(QPainter::Antialiasing));
        painter.translate(-offset);
        painter.setPen(p->pen());
        painter.setBrush(p->brush());
        painter.setTransform(p->transform(), true);
        painter.setOpacity(p->opacity());
        painter.setFont(p->font());
        if (painter.paintEngine()->hasFeature(QPaintEngine::PorterDuff))
            painter.setCompositionMode(p->compositionMode());
        painter.setClipPath(p->clipPath());
    }

    TransparencyLayer()
    {
    }

    QPixmap pixmap;
    QPoint offset;
    QPainter painter;
    qreal opacity;
private:
    TransparencyLayer(const TransparencyLayer &) {}
    TransparencyLayer & operator=(const TransparencyLayer &) { return *this; }
};

class GraphicsContextPlatformPrivate
{
public:
    GraphicsContextPlatformPrivate(QPainter* painter);
    ~GraphicsContextPlatformPrivate();

    inline QPainter* p()
    {
        if (layers.isEmpty()) {
            if (redirect)
                return redirect;

            return painter;
        } else
            return &layers.top()->painter;
    }

    bool antiAliasingForRectsAndLines;

    QStack<TransparencyLayer *> layers;
    QPainter* redirect;

    QBrush solidColor;

    // Only used by SVG for now.
    QPainterPath currentPath;

private:
    QPainter* painter;
};


GraphicsContextPlatformPrivate::GraphicsContextPlatformPrivate(QPainter* p)
{
    painter = p;
    redirect = 0;

    solidColor = QBrush(Qt::black);

    if (painter) {
        // use the default the QPainter was constructed with
        antiAliasingForRectsAndLines = painter->testRenderHint(QPainter::Antialiasing);
        // FIXME: Maybe only enable in SVG mode?
        painter->setRenderHint(QPainter::Antialiasing, true);
    } else {
        antiAliasingForRectsAndLines = false;
    }
}

GraphicsContextPlatformPrivate::~GraphicsContextPlatformPrivate()
{
}

GraphicsContext::GraphicsContext(PlatformGraphicsContext* context)
    : m_common(createGraphicsContextPrivate())
    , m_data(new GraphicsContextPlatformPrivate(context))
{
    setPaintingDisabled(!context);
    if (context) {
        // Make sure the context starts in sync with our state.
        setPlatformFillColor(fillColor());
        setPlatformStrokeColor(strokeColor());
    }
}

GraphicsContext::~GraphicsContext()
{
    while(!m_data->layers.isEmpty())
        endTransparencyLayer();

    destroyGraphicsContextPrivate(m_common);
    delete m_data;
}

PlatformGraphicsContext* GraphicsContext::platformContext() const
{
    return m_data->p();
}

TransformationMatrix GraphicsContext::getCTM() const
{
    QTransform matrix(platformContext()->combinedTransform());
    return TransformationMatrix(matrix.m11(), matrix.m12(), 0, matrix.m13(), 
                                matrix.m21(), matrix.m22(), 0, matrix.m23(),
                                           0,            0, 1,            0,
                                matrix.m31(), matrix.m32(), 0, matrix.m33());
}

void GraphicsContext::savePlatformState()
{
    m_data->p()->save();
}

void GraphicsContext::restorePlatformState()
{
    m_data->p()->restore();

    if (!m_data->currentPath.isEmpty() && m_common->state.pathTransform.isInvertible()) {
        QTransform matrix = m_common->state.pathTransform;
        m_data->currentPath = m_data->currentPath * matrix;
    }
}

/* FIXME: DISABLED WHILE MERGING BACK FROM UNITY
void GraphicsContext::drawTextShadow(const TextRun& run, const IntPoint& point, const FontStyle& style)
{
    if (paintingDisabled())
        return;

    if (m_data->shadow.isNull())
        return;

    TextShadow* shadow = &m_data->shadow;

    if (shadow->blur <= 0) {
        Pen p = pen();
        setPen(shadow->color);
        font().drawText(this, run, style, IntPoint(point.x() + shadow->x, point.y() + shadow->y));
        setPen(p);
    } else {
        const int thickness = shadow->blur;
        // FIXME: OPTIMIZE: limit the area to only the actually painted area + 2*thickness
        const int w = m_data->p()->device()->width();
        const int h = m_data->p()->device()->height();
        const QRgb color = qRgb(255, 255, 255);
        const QRgb bgColor = qRgb(0, 0, 0);
        QImage image(QSize(w, h), QImage::Format_ARGB32);
        image.fill(bgColor);
        QPainter p;

        Pen curPen = pen();
        p.begin(&image);
        setPen(color);
        m_data->redirect = &p;
        font().drawText(this, run, style, IntPoint(point.x() + shadow->x, point.y() + shadow->y));
        m_data->redirect = 0;
        p.end();
        setPen(curPen);

        int md = thickness * thickness; // max-dist^2

        // blur map/precalculated shadow-decay
        float* bmap = (float*) alloca(sizeof(float) * (md + 1));
        for (int n = 0; n <= md; n++) {
            float f;
            f = n / (float) (md + 1);
            f = 1.0 - f * f;
            bmap[n] = f;
        }

        float factor = 0.0; // maximal potential opacity-sum
        for (int n = -thickness; n <= thickness; n++) {
            for (int m = -thickness; m <= thickness; m++) {
                int d = n * n + m * m;
                if (d <= md)
                    factor += bmap[d];
            }
        }

        // alpha map
        float* amap = (float*) alloca(sizeof(float) * (h * w));
        memset(amap, 0, h * w * (sizeof(float)));

        for (int j = thickness; j<h-thickness; j++) {
            for (int i = thickness; i<w-thickness; i++) {
                QRgb col = image.pixel(i,j);
                if (col == bgColor)
                    continue;

                float g = qAlpha(col);
                g = g / 255;

                for (int n = -thickness; n <= thickness; n++) {
                    for (int m = -thickness; m <= thickness; m++) {
                        int d = n * n + m * m;
                        if (d > md)
                            continue;

                        float f = bmap[d];
                        amap[(i + m) + (j + n) * w] += (g * f);
                    }
                }
            }
        }

        QImage res(QSize(w,h),QImage::Format_ARGB32);
        int r = shadow->color.red();
        int g = shadow->color.green();
        int b = shadow->color.blue();
        int a1 = shadow->color.alpha();

        // arbitratry factor adjustment to make shadows more solid.
        factor = 1.333 / factor;

        for (int j = 0; j < h; j++) {
            for (int i = 0; i < w; i++) {
                int a = (int) (amap[i + j * w] * factor * a1);
                if (a > 255)
                    a = 255;

                res.setPixel(i,j, qRgba(r, g, b, a));
            }
        }

        m_data->p()->drawImage(0, 0, res, 0, 0, -1, -1, Qt::DiffuseAlphaDither | Qt::ColorOnly | Qt::PreferDither);
    }
}
*/

// Draws a filled rectangle with a stroked border.