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Branched from the monolithic repo, Qt master branch, at commit
896db169ea224deb96c59ce8af800d019de63f12

1 files changed, 824 insertions, 0 deletions

diff --git a/examples/script/context2d/context2d.cpp b/examples/script/context2d/context2d.cpp
new file mode 100644
index 0000000..ca6c85e
--- /dev/null
+++ b/examples/script/context2d/context2d.cpp
@@ -0,0 +1,824 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * 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.
+**   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
+**     the names of its contributors may be used to endorse or promote
+**     products derived from this software without specific prior written
+**     permission.
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "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 THE COPYRIGHT
+** OWNER 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."
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "context2d.h"
+
+#include <QVariant>
+
+#include <math.h>
+static const double Q_PI   = 3.14159265358979323846;   // pi
+
+#define DEGREES(t) ((t) * 180.0 / Q_PI)
+
+#define qClamp(val, min, max) qMin(qMax(val, min), max)
+static QList<qreal> parseNumbersList(QString::const_iterator &itr)
+{
+    QList<qreal> points;
+    QString temp;
+    while ((*itr).isSpace())
+        ++itr;
+    while ((*itr).isNumber() ||
+           (*itr) == '-' || (*itr) == '+' || (*itr) == '.') {
+        temp = QString();
+
+        if ((*itr) == '-')
+            temp += *itr++;
+        else if ((*itr) == '+')
+            temp += *itr++;
+        while ((*itr).isDigit())
+            temp += *itr++;
+        if ((*itr) == '.')
+            temp += *itr++;
+        while ((*itr).isDigit())
+            temp += *itr++;
+        while ((*itr).isSpace())
+            ++itr;
+        if ((*itr) == ',')
+            ++itr;
+        points.append(temp.toDouble());
+        //eat spaces
+        while ((*itr).isSpace())
+            ++itr;
+    }
+
+    return points;
+}
+
+QColor colorFromString(const QString &name)
+{
+    QString::const_iterator itr = name.constBegin();
+    QList<qreal> compo;
+    if (name.startsWith("rgba(")) {
+        ++itr; ++itr; ++itr; ++itr; ++itr;
+        compo = parseNumbersList(itr);
+        if (compo.size() != 4) {
+            return QColor();
+        }
+        //alpha seems to be always between 0-1
+        compo[3] *= 255;
+        return QColor((int)compo[0], (int)compo[1],
+                      (int)compo[2], (int)compo[3]);
+    } else if (name.startsWith("rgb(")) {
+        ++itr; ++itr; ++itr; ++itr;
+        compo = parseNumbersList(itr);
+        if (compo.size() != 3) {
+            return QColor();
+        }
+        return QColor((int)qClamp(compo[0], qreal(0), qreal(255)),
+                      (int)qClamp(compo[1], qreal(0), qreal(255)),
+                      (int)qClamp(compo[2], qreal(0), qreal(255)));
+    } else {
+        //QRgb color;
+        //CSSParser::parseColor(name, color);
+        return QColor(name);
+    }
+}
+
+
+static QPainter::CompositionMode compositeOperatorFromString(const QString &compositeOperator)
+{
+    if ( compositeOperator == "source-over" ) {
+        return QPainter::CompositionMode_SourceOver;
+    } else if ( compositeOperator == "source-out" ) {
+        return QPainter::CompositionMode_SourceOut;
+    } else if ( compositeOperator == "source-in" ) {
+        return QPainter::CompositionMode_SourceIn;
+    } else if ( compositeOperator == "source-atop" ) {
+        return QPainter::CompositionMode_SourceAtop;
+    } else if ( compositeOperator == "destination-atop" ) {
+        return QPainter::CompositionMode_DestinationAtop;
+    } else if ( compositeOperator == "destination-in" ) {
+        return QPainter::CompositionMode_DestinationIn;
+    } else if ( compositeOperator == "destination-out" ) {
+        return QPainter::CompositionMode_DestinationOut;
+    } else if ( compositeOperator == "destination-over" ) {
+        return QPainter::CompositionMode_DestinationOver;
+    } else if ( compositeOperator == "darker" ) {
+        return QPainter::CompositionMode_SourceOver;
+    } else if ( compositeOperator == "lighter" ) {
+        return QPainter::CompositionMode_SourceOver;
+    } else if ( compositeOperator == "copy" ) {
+        return QPainter::CompositionMode_Source;
+    } else if ( compositeOperator == "xor" ) {
+        return QPainter::CompositionMode_Xor;
+    }
+
+    return QPainter::CompositionMode_SourceOver;
+}
+
+static QString compositeOperatorToString(QPainter::CompositionMode op)
+{
+    switch (op) {
+    case QPainter::CompositionMode_SourceOver:
+        return "source-over";
+    case QPainter::CompositionMode_DestinationOver:
+        return "destination-over";
+    case QPainter::CompositionMode_Clear:
+        return "clear";
+    case QPainter::CompositionMode_Source:
+        return "source";
+    case QPainter::CompositionMode_Destination:
+        return "destination";
+    case QPainter::CompositionMode_SourceIn:
+        return "source-in";
+    case QPainter::CompositionMode_DestinationIn:
+        return "destination-in";
+    case QPainter::CompositionMode_SourceOut:
+        return "source-out";
+    case QPainter::CompositionMode_DestinationOut:
+        return "destination-out";
+    case QPainter::CompositionMode_SourceAtop:
+        return "source-atop";
+    case QPainter::CompositionMode_DestinationAtop:
+        return "destination-atop";
+    case QPainter::CompositionMode_Xor:
+        return "xor";
+    case QPainter::CompositionMode_Plus:
+        return "plus";
+    case QPainter::CompositionMode_Multiply:
+        return "multiply";
+    case QPainter::CompositionMode_Screen:
+        return "screen";
+    case QPainter::CompositionMode_Overlay:
+        return "overlay";
+    case QPainter::CompositionMode_Darken:
+        return "darken";
+    case QPainter::CompositionMode_Lighten:
+        return "lighten";
+    case QPainter::CompositionMode_ColorDodge:
+        return "color-dodge";
+    case QPainter::CompositionMode_ColorBurn:
+        return "color-burn";
+    case QPainter::CompositionMode_HardLight:
+        return "hard-light";
+    case QPainter::CompositionMode_SoftLight:
+        return "soft-light";
+    case QPainter::CompositionMode_Difference:
+        return "difference";
+    case QPainter::CompositionMode_Exclusion:
+        return "exclusion";
+    default:
+        break;
+    }
+    return QString();
+}
+
+void Context2D::save()
+{
+    m_stateStack.push(m_state);
+}
+
+
+void Context2D::restore()
+{
+    if (!m_stateStack.isEmpty()) {
+        m_state = m_stateStack.pop();
+        m_state.flags = AllIsFullOfDirt;
+    }
+}
+
+
+void Context2D::scale(qreal x, qreal y)
+{
+    m_state.matrix.scale(x, y);
+    m_state.flags |= DirtyTransformationMatrix;
+}
+
+
+void Context2D::rotate(qreal angle)
+{
+    m_state.matrix.rotate(DEGREES(angle));
+    m_state.flags |= DirtyTransformationMatrix;
+}
+
+
+void Context2D::translate(qreal x, qreal y)
+{
+    m_state.matrix.translate(x, y);
+    m_state.flags |= DirtyTransformationMatrix;
+}
+
+
+void Context2D::transform(qreal m11, qreal m12, qreal m21, qreal m22,
+                          qreal dx, qreal dy)
+{
+    QMatrix mat(m11, m12,
+                m21, m22,
+                dx, dy);
+    m_state.matrix *= mat;
+    m_state.flags |= DirtyTransformationMatrix;
+}
+
+
+void Context2D::setTransform(qreal m11, qreal m12, qreal m21, qreal m22,
+                             qreal dx, qreal dy)
+{
+    QMatrix mat(m11, m12,
+                m21, m22,
+                dx, dy);
+    m_state.matrix = mat;
+    m_state.flags |= DirtyTransformationMatrix;
+}
+
+
+QString Context2D::globalCompositeOperation() const
+{
+    return compositeOperatorToString(m_state.globalCompositeOperation);
+}
+
+void Context2D::setGlobalCompositeOperation(const QString &op)
+{
+    QPainter::CompositionMode mode =
+        compositeOperatorFromString(op);
+    m_state.globalCompositeOperation = mode;
+    m_state.flags |= DirtyGlobalCompositeOperation;
+}
+
+QVariant Context2D::strokeStyle() const
+{
+    return m_state.strokeStyle;
+}
+
+void Context2D::setStrokeStyle(const QVariant &style)
+{
+    if (style.canConvert<CanvasGradient>()) {
+        CanvasGradient cg = qvariant_cast<CanvasGradient>(style);
+        m_state.strokeStyle = cg.value;
+    } else {
+        QColor color = colorFromString(style.toString());
+        m_state.strokeStyle = color;
+    }
+    m_state.flags |= DirtyStrokeStyle;
+}
+
+QVariant Context2D::fillStyle() const
+{
+    return m_state.fillStyle;
+}
+
+//! [3]
+void Context2D::setFillStyle(const QVariant &style)
+{
+    if (style.canConvert<CanvasGradient>()) {
+        CanvasGradient cg = qvariant_cast<CanvasGradient>(style);
+        m_state.fillStyle = cg.value;
+    } else {
+        QColor color = colorFromString(style.toString());
+        m_state.fillStyle = color;
+    }
+    m_state.flags |= DirtyFillStyle;
+}
+//! [3]
+
+qreal Context2D::globalAlpha() const
+{
+    return m_state.globalAlpha;
+}
+
+void Context2D::setGlobalAlpha(qreal alpha)
+{
+    m_state.globalAlpha = alpha;
+    m_state.flags |= DirtyGlobalAlpha;
+}
+
+
+CanvasGradient Context2D::createLinearGradient(qreal x0, qreal y0,
+                                               qreal x1, qreal y1)
+{
+    QLinearGradient g(x0, y0, x1, y1);
+    return CanvasGradient(g);
+}
+
+
+CanvasGradient Context2D::createRadialGradient(qreal x0, qreal y0,
+                                               qreal r0, qreal x1,
+                                               qreal y1, qreal r1)
+{
+    QRadialGradient g(QPointF(x1, y1), r0+r1, QPointF(x0, y0));
+    return CanvasGradient(g);
+}
+
+qreal Context2D::lineWidth() const
+{
+    return m_state.lineWidth;
+}
+
+void Context2D::setLineWidth(qreal w)
+{
+    m_state.lineWidth = w;
+    m_state.flags |= DirtyLineWidth;
+}
+
+//! [0]
+QString Context2D::lineCap() const
+{
+    switch (m_state.lineCap) {
+    case Qt::FlatCap:
+        return "butt";
+    case Qt::SquareCap:
+        return "square";
+    case Qt::RoundCap:
+        return "round";
+    default: ;
+    }
+    return QString();
+}
+
+void Context2D::setLineCap(const QString &capString)
+{
+    Qt::PenCapStyle style;
+    if (capString == "round")
+        style = Qt::RoundCap;
+    else if (capString == "square")
+        style = Qt::SquareCap;
+    else //if (capString == "butt")
+        style = Qt::FlatCap;
+    m_state.lineCap = style;
+    m_state.flags |= DirtyLineCap;
+}
+//! [0]
+
+QString Context2D::lineJoin() const
+{
+    switch (m_state.lineJoin) {
+    case Qt::RoundJoin:
+        return "round";
+    case Qt::BevelJoin:
+        return "bevel";
+    case Qt::MiterJoin:
+        return "miter";
+    default: ;
+    }
+    return QString();
+}
+
+void Context2D::setLineJoin(const QString &joinString)
+{
+    Qt::PenJoinStyle style;
+    if (joinString == "round")
+        style = Qt::RoundJoin;
+    else if (joinString == "bevel")
+        style = Qt::BevelJoin;
+    else //if (joinString == "miter")
+        style = Qt::MiterJoin;
+    m_state.lineJoin = style;
+    m_state.flags |= DirtyLineJoin;
+}
+
+qreal Context2D::miterLimit() const
+{
+    return m_state.miterLimit;
+}
+
+void Context2D::setMiterLimit(qreal m)
+{
+    m_state.miterLimit = m;
+    m_state.flags |= DirtyMiterLimit;
+}
+
+void Context2D::setShadowOffsetX(qreal x)
+{
+    m_state.shadowOffsetX = x;
+    m_state.flags |= DirtyShadowOffsetX;
+}
+
+void Context2D::setShadowOffsetY(qreal y)
+{
+    m_state.shadowOffsetY = y;
+    m_state.flags |= DirtyShadowOffsetY;
+}
+
+void Context2D::setShadowBlur(qreal b)
+{
+    m_state.shadowBlur = b;
+    m_state.flags |= DirtyShadowBlur;
+}
+
+void Context2D::setShadowColor(const QString &str)
+{
+    m_state.shadowColor = colorFromString(str);
+    m_state.flags |= DirtyShadowColor;
+}
+
+qreal Context2D::shadowOffsetX() const
+{
+    return m_state.shadowOffsetX;
+}
+
+qreal Context2D::shadowOffsetY() const
+{
+    return m_state.shadowOffsetY;
+}
+
+
+qreal Context2D::shadowBlur() const
+{
+    return m_state.shadowBlur;
+}
+
+
+QString Context2D::shadowColor() const
+{
+    return m_state.shadowColor.name();
+}
+
+
+void Context2D::clearRect(qreal x, qreal y, qreal w, qreal h)
+{
+    beginPainting();
+    m_painter.save();
+    m_painter.setMatrix(m_state.matrix, false);
+    m_painter.setCompositionMode(QPainter::CompositionMode_Source);
+    m_painter.fillRect(QRectF(x, y, w, h), QColor(0, 0, 0, 0));
+    m_painter.restore();
+    scheduleChange();
+}
+
+
+//! [1]
+void Context2D::fillRect(qreal x, qreal y, qreal w, qreal h)
+{
+    beginPainting();
+    m_painter.save();
+    m_painter.setMatrix(m_state.matrix, false);
+    m_painter.fillRect(QRectF(x, y, w, h), m_painter.brush());
+    m_painter.restore();
+    scheduleChange();
+}
+//! [1]
+
+
+void Context2D::strokeRect(qreal x, qreal y, qreal w, qreal h)
+{
+    QPainterPath path;
+    path.addRect(x, y, w, h);
+    beginPainting();
+    m_painter.save();
+    m_painter.setMatrix(m_state.matrix, false);
+    m_painter.strokePath(path, m_painter.pen());
+    m_painter.restore();
+    scheduleChange();
+}
+
+
+void Context2D::beginPath()
+{
+    m_path = QPainterPath();
+}
+
+
+void Context2D::closePath()
+{
+    m_path.closeSubpath();
+}
+
+
+void Context2D::moveTo(qreal x, qreal y)
+{
+    QPointF pt = m_state.matrix.map(QPointF(x, y));
+    m_path.moveTo(pt);
+}
+
+
+void Context2D::lineTo(qreal x, qreal y)
+{
+    QPointF pt = m_state.matrix.map(QPointF(x, y));
+    m_path.lineTo(pt);
+}
+
+
+void Context2D::quadraticCurveTo(qreal cpx, qreal cpy, qreal x, qreal y)
+{
+    QPointF cp = m_state.matrix.map(QPointF(cpx, cpy));
+    QPointF xy = m_state.matrix.map(QPointF(x, y));
+    m_path.quadTo(cp, xy);
+}
+
+
+void Context2D::bezierCurveTo(qreal cp1x, qreal cp1y,
+                              qreal cp2x, qreal cp2y, qreal x, qreal y)
+{
+    QPointF cp1 = m_state.matrix.map(QPointF(cp1x, cp1y));
+    QPointF cp2 = m_state.matrix.map(QPointF(cp2x, cp2y));
+    QPointF end = m_state.matrix.map(QPointF(x, y));
+    m_path.cubicTo(cp1, cp2, end);
+}
+
+
+void Context2D::arcTo(qreal x1, qreal y1, qreal x2, qreal y2, qreal radius)
+{
+    //FIXME: this is surely busted
+    QPointF st  = m_state.matrix.map(QPointF(x1, y1));
+    QPointF end = m_state.matrix.map(QPointF(x2, y2));
+    m_path.arcTo(st.x(), st.y(),
+                 end.x()-st.x(), end.y()-st.y(),
+                 radius, 90);
+}
+
+
+void Context2D::rect(qreal x, qreal y, qreal w, qreal h)
+{
+    QPainterPath path; path.addRect(x, y, w, h);
+    path = m_state.matrix.map(path);
+    m_path.addPath(path);
+}
+
+void Context2D::arc(qreal xc, qreal yc, qreal radius,
+                    qreal sar, qreal ear,
+                    bool anticlockwise)
+{
+    //### HACK
+    // In Qt we don't switch the coordinate system for degrees
+    // and still use the 0,0 as bottom left for degrees so we need
+    // to switch
+    sar = -sar;
+    ear = -ear;
+    anticlockwise = !anticlockwise;
+    //end hack
+
+    float sa = DEGREES(sar);
+    float ea = DEGREES(ear);
+
+    double span = 0;
+
+    double xs     = xc - radius;
+    double ys     = yc - radius;
+    double width  = radius*2;
+    double height = radius*2;
+
+    if (!anticlockwise && (ea < sa)) {
+        span += 360;
+    } else if (anticlockwise && (sa < ea)) {
+        span -= 360;
+    }
+
+    //### this is also due to switched coordinate system
+    // we would end up with a 0 span instead of 360
+    if (!(qFuzzyCompare(span + (ea - sa) + 1, 1) &&
+          qFuzzyCompare(qAbs(span), 360))) {
+        span   += ea - sa;
+    }
+
+    QPainterPath path;
+    path.moveTo(QPointF(xc + radius  * cos(sar),
+                                yc - radius  * sin(sar)));
+
+    path.arcTo(xs, ys, width, height, sa, span);
+    path = m_state.matrix.map(path);
+    m_path.addPath(path);
+}
+
+
+void Context2D::fill()
+{
+    beginPainting();
+    m_painter.fillPath(m_path, m_painter.brush());
+    scheduleChange();
+}
+
+
+void Context2D::stroke()
+{
+    beginPainting();
+    m_painter.save();
+    m_painter.setMatrix(m_state.matrix, false);
+    QPainterPath tmp = m_state.matrix.inverted().map(m_path);
+    m_painter.strokePath(tmp, m_painter.pen());
+    m_painter.restore();
+    scheduleChange();
+}
+
+
+void Context2D::clip()
+{
+    m_state.clipPath = m_path;
+    m_state.flags |= DirtyClippingRegion;
+}
+
+
+bool Context2D::isPointInPath(qreal x, qreal y) const
+{
+    return m_path.contains(QPointF(x, y));
+}
+
+
+ImageData Context2D::getImageData(qreal sx, qreal sy, qreal sw, qreal sh)
+{
+    Q_UNUSED(sx);
+    Q_UNUSED(sy);
+    Q_UNUSED(sw);
+    Q_UNUSED(sh);
+    return ImageData();
+}
+
+
+void Context2D::putImageData(ImageData image, qreal dx, qreal dy)
+{
+    Q_UNUSED(image);
+    Q_UNUSED(dx);
+    Q_UNUSED(dy);
+}
+
+Context2D::Context2D(QObject *parent)
+    : QObject(parent), m_changeTimerId(-1)
+{
+    reset();
+}
+
+const QImage &Context2D::endPainting()
+{
+    if (m_painter.isActive())
+        m_painter.end();
+    return m_image;
+}
+
+void Context2D::beginPainting()
+{
+    if (!m_painter.isActive()) {
+        m_painter.begin(&m_image);
+        m_painter.setRenderHint(QPainter::Antialiasing);
+        if (!m_state.clipPath.isEmpty())
+            m_painter.setClipPath(m_state.clipPath);
+        m_painter.setBrush(m_state.fillStyle);
+        m_painter.setOpacity(m_state.globalAlpha);
+        QPen pen;
+        pen.setBrush(m_state.strokeStyle);
+        if (pen.style() == Qt::NoPen)
+            pen.setStyle(Qt::SolidLine);
+        pen.setCapStyle(m_state.lineCap);
+        pen.setJoinStyle(m_state.lineJoin);
+        pen.setWidthF(m_state.lineWidth);
+        pen.setMiterLimit(m_state.miterLimit);
+        m_painter.setPen(pen);
+    } else {
+        if ((m_state.flags & DirtyClippingRegion) && !m_state.clipPath.isEmpty())
+            m_painter.setClipPath(m_state.clipPath);
+        if (m_state.flags & DirtyFillStyle)
+            m_painter.setBrush(m_state.fillStyle);
+        if (m_state.flags & DirtyGlobalAlpha)
+            m_painter.setOpacity(m_state.globalAlpha);
+        if (m_state.flags & DirtyGlobalCompositeOperation)
+            m_painter.setCompositionMode(m_state.globalCompositeOperation);
+        if (m_state.flags & MDirtyPen) {
+            QPen pen = m_painter.pen();
+            if (m_state.flags & DirtyStrokeStyle)
+                pen.setBrush(m_state.strokeStyle);
+            if (m_state.flags & DirtyLineWidth)
+                pen.setWidthF(m_state.lineWidth);
+            if (m_state.flags & DirtyLineCap)
+                pen.setCapStyle(m_state.lineCap);
+            if (m_state.flags & DirtyLineJoin)
+                pen.setJoinStyle(m_state.lineJoin);
+            if (m_state.flags & DirtyMiterLimit)
+                pen.setMiterLimit(m_state.miterLimit);
+            m_painter.setPen(pen);
+        }
+        m_state.flags = 0;
+    }
+}
+
+void Context2D::clear()
+{
+    endPainting();
+    m_image.fill(qRgba(0,0,0,0));
+    scheduleChange();
+}
+
+void Context2D::reset()
+{
+    m_stateStack.clear();
+    m_state.matrix = QMatrix();
+    m_state.clipPath = QPainterPath();
+    m_state.globalAlpha = 1.0;
+    m_state.globalCompositeOperation = QPainter::CompositionMode_SourceOver;
+    m_state.strokeStyle = Qt::black;
+    m_state.fillStyle = Qt::black;
+    m_state.lineWidth = 1;
+    m_state.lineCap = Qt::FlatCap;
+    m_state.lineJoin = Qt::MiterJoin;
+    m_state.miterLimit = 10;
+    m_state.shadowOffsetX = 0;
+    m_state.shadowOffsetY = 0;
+    m_state.shadowBlur = 0;
+    m_state.shadowColor = qRgba(0, 0, 0, 0);
+    m_state.flags = AllIsFullOfDirt;
+    clear();
+}
+
+void Context2D::setSize(int width, int height)
+{
+    endPainting();
+    QImage newi(width, height, QImage::Format_ARGB32_Premultiplied);
+    newi.fill(qRgba(0,0,0,0));
+    QPainter p(&newi);
+    p.drawImage(0, 0, m_image);
+    p.end();
+    m_image = newi;
+    scheduleChange();
+}
+
+void Context2D::setSize(const QSize &size)
+{
+    setSize(size.width(), size.height());
+}
+
+QSize Context2D::size() const
+{
+    return m_image.size();
+}
+
+void Context2D::drawImage(DomImage *image, qreal dx, qreal dy)
+{
+    if (!image)
+        return;
+    if (dx < 0) {
+        qreal sx = qAbs(dx);
+        qreal sy = qAbs(dy);
+        qreal sw = image->width() - sx;
+        qreal sh = image->height() - sy;
+
+        drawImage(image, sx, sy, sw, sh, 0, 0, sw, sh);
+    } else {
+        beginPainting();
+        m_painter.drawImage(QPointF(dx, dy), image->image());
+        scheduleChange();
+    }
+}
+
+void Context2D::drawImage(DomImage *image, qreal dx, qreal dy,
+                          qreal dw, qreal dh)
+{
+    if (!image)
+        return;
+    beginPainting();
+    m_painter.drawImage(QRectF(dx, dy, dw, dh).toRect(), image->image());
+    scheduleChange();
+}
+
+void Context2D::drawImage(DomImage *image, qreal sx, qreal sy,
+                          qreal sw, qreal sh, qreal dx, qreal dy,
+                          qreal dw, qreal dh)
+{
+    if (!image)
+        return;
+    beginPainting();
+    m_painter.drawImage(QRectF(dx, dy, dw, dh), image->image(),
+                        QRectF(sx, sy, sw, sh));
+    scheduleChange();
+}
+
+//! [2]
+void Context2D::scheduleChange()
+{
+    if (m_changeTimerId == -1)
+        m_changeTimerId = startTimer(0);
+}
+
+void Context2D::timerEvent(QTimerEvent *e)
+{
+    if (e->timerId() == m_changeTimerId) {
+        killTimer(m_changeTimerId);
+        m_changeTimerId = -1;
+        emit changed(endPainting());
+    } else {
+        QObject::timerEvent(e);
+    }
+}
+//! [2]