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# pathstroke.cpp Example File
demos/pathstroke/pathstroke.cpp

        /****************************************************************************
        **
        ** Copyright (C) 2005-2006 Trolltech ASA. All rights reserved.
        **
        ** This file is part of the documentation of the Qt Toolkit.
        **
        ** This file may be used under the terms of the GNU General Public
        ** License version 2.0 as published by the Free Software Foundation
        ** and appearing in the file LICENSE.GPL included in the packaging of
        ** this file.  Please review the following information to ensure GNU
        ** General Public Licensing requirements will be met:
        ** http://www.trolltech.com/products/qt/opensource.html
        **
        ** If you are unsure which license is appropriate for your use, please
        ** review the following information:
        ** http://www.trolltech.com/products/qt/licensing.html or contact the
        ** sales department at sales@trolltech.com.
        **
        ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
        ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        **
        ****************************************************************************/

        #include "pathstroke.h"
        #include "arthurstyle.h"
        #include "arthurwidgets.h"

        extern void draw_round_rect(QPainter *p, const QRect &bounds, int radius);

        PathStrokeWidget::PathStrokeWidget()
        {
            setWindowTitle(tr("Path Stroking"));

            // Setting up palette.
            QPalette pal = palette();
        //     pal.setBrush(QPalette::Background, Qt::white);
        //     pal.setBrush(QPalette::Foreground, QColor("aquamarine"));
        //     pal.setBrush(QPalette::Background, QPixmap("background.png"));
            setPalette(pal);

            // Widget construction and property setting
            m_renderer = new PathStrokeRenderer(this);

            QGroupBox *mainGroup = new QGroupBox(this);
        //     QWidget *mainGroup = new QWidget(this);
            mainGroup->setFixedWidth(180);
            mainGroup->setTitle("Path Stroking");

            QGroupBox *capGroup = new QGroupBox(mainGroup);
            capGroup->setAttribute(Qt::WA_ContentsPropagated);
            QRadioButton *flatCap = new QRadioButton(capGroup);
            QRadioButton *squareCap = new QRadioButton(capGroup);
            QRadioButton *roundCap = new QRadioButton(capGroup);
            capGroup->setTitle("Cap Style");
            flatCap->setText("Flat Cap");
            squareCap->setText("Square Cap");
            roundCap->setText("Round Cap");

            QGroupBox *joinGroup = new QGroupBox(mainGroup);
            joinGroup->setAttribute(Qt::WA_ContentsPropagated);
            QRadioButton *bevelJoin = new QRadioButton(joinGroup);
            QRadioButton *miterJoin = new QRadioButton(joinGroup);
            QRadioButton *roundJoin = new QRadioButton(joinGroup);
            joinGroup->setTitle("Join Style");
            bevelJoin->setText("Bevel Join");
            miterJoin->setText("Miter Join");
            roundJoin->setText("Round Join");

            QGroupBox *styleGroup = new QGroupBox(mainGroup);
            styleGroup->setAttribute(Qt::WA_ContentsPropagated);
            QRadioButton *solidLine = new QRadioButton(styleGroup);
            QRadioButton *dashLine = new QRadioButton(styleGroup);
            QRadioButton *dotLine = new QRadioButton(styleGroup);
            QRadioButton *dashDotLine = new QRadioButton(styleGroup);
            QRadioButton *dashDotDotLine = new QRadioButton(styleGroup);
            QRadioButton *customDashLine = new QRadioButton(styleGroup);
            styleGroup->setTitle("Pen Style");
        #if 0
            solidLine->setText("Solid Line");
            dashLine->setText("Dash Line");
            dotLine->setText("Dot Line");
            dashDotLine->setText("Dash Dot Line");
            dashDotDotLine->setText("Dash Dot Dot Line");
        #else
            solidLine->setIcon(QPixmap(":res/images/line_solid.png"));
            dashLine->setIcon(QPixmap(":res/images/line_dashed.png"));
            dotLine->setIcon(QPixmap(":res/images/line_dotted.png"));
            dashDotLine->setIcon(QPixmap(":res/images/line_dash_dot.png"));
            dashDotDotLine->setIcon(QPixmap(":res/images/line_dash_dot_dot.png"));
            customDashLine->setText("Custom Style");

            int fixedHeight = bevelJoin->sizeHint().height();
            solidLine->setFixedHeight(fixedHeight);
            dashLine->setFixedHeight(fixedHeight);
            dotLine->setFixedHeight(fixedHeight);
            dashDotLine->setFixedHeight(fixedHeight);
            dashDotDotLine->setFixedHeight(fixedHeight);
        #endif

            QGroupBox *pathModeGroup = new QGroupBox(mainGroup);
            pathModeGroup->setAttribute(Qt::WA_ContentsPropagated);
            QRadioButton *curveMode = new QRadioButton(pathModeGroup);
            QRadioButton *lineMode = new QRadioButton(pathModeGroup);
            pathModeGroup->setTitle("Path composed of");
            curveMode->setText("Curves");
            lineMode->setText("Lines");

            QGroupBox *penWidthGroup = new QGroupBox(mainGroup);
            penWidthGroup->setAttribute(Qt::WA_ContentsPropagated);
            QSlider *penWidth = new QSlider(Qt::Horizontal, penWidthGroup);
            penWidth->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);
            penWidthGroup->setTitle("Pen Width");
            penWidth->setRange(0, 500);

        #if 0
            QCheckBox *animated = new QCheckBox(mainGroup);
            animated->setText("Animated");
        #else
            QPushButton *animated = new QPushButton(mainGroup);
            animated->setText("Animate");
            animated->setCheckable(true);
        #endif

            QPushButton *showSourceButton = new QPushButton(mainGroup);
            showSourceButton->setText("Show Source");

            QPushButton *whatsThisButton = new QPushButton(mainGroup);
            whatsThisButton->setText("What's This?");
            whatsThisButton->setCheckable(true);

            // Layouting
            QHBoxLayout *viewLayout = new QHBoxLayout(this);
            viewLayout->addWidget(m_renderer);
            viewLayout->addWidget(mainGroup);

            QVBoxLayout *mainGroupLayout = new QVBoxLayout(mainGroup);
            mainGroupLayout->setMargin(3);
            mainGroupLayout->addWidget(capGroup);
            mainGroupLayout->addWidget(joinGroup);
            mainGroupLayout->addWidget(styleGroup);
            mainGroupLayout->addWidget(penWidthGroup);
            mainGroupLayout->addWidget(pathModeGroup);
            mainGroupLayout->addWidget(animated);
            mainGroupLayout->addStretch(1);
            mainGroupLayout->addWidget(showSourceButton);
            mainGroupLayout->addWidget(whatsThisButton);

            QVBoxLayout *capGroupLayout = new QVBoxLayout(capGroup);
            capGroupLayout->addWidget(flatCap);
            capGroupLayout->addWidget(squareCap);
            capGroupLayout->addWidget(roundCap);

            QVBoxLayout *joinGroupLayout = new QVBoxLayout(joinGroup);
            joinGroupLayout->addWidget(bevelJoin);
            joinGroupLayout->addWidget(miterJoin);
            joinGroupLayout->addWidget(roundJoin);

            QVBoxLayout *styleGroupLayout = new QVBoxLayout(styleGroup);
            styleGroupLayout->addWidget(solidLine);
            styleGroupLayout->addWidget(dashLine);
            styleGroupLayout->addWidget(dotLine);
            styleGroupLayout->addWidget(dashDotLine);
            styleGroupLayout->addWidget(dashDotDotLine);
            styleGroupLayout->addWidget(customDashLine);

            QVBoxLayout *pathModeGroupLayout = new QVBoxLayout(pathModeGroup);
            pathModeGroupLayout->addWidget(curveMode);
            pathModeGroupLayout->addWidget(lineMode);

            QVBoxLayout *penWidthLayout = new QVBoxLayout(penWidthGroup);
            penWidthLayout->addWidget(penWidth);

            // Set up connections
            connect(penWidth, SIGNAL(valueChanged(int)),
                    m_renderer, SLOT(setPenWidth(int)));
            connect(animated, SIGNAL(toggled(bool)),
                    m_renderer, SLOT(setAnimation(bool)));

            connect(flatCap, SIGNAL(clicked()), m_renderer, SLOT(setFlatCap()));
            connect(squareCap, SIGNAL(clicked()), m_renderer, SLOT(setSquareCap()));
            connect(roundCap, SIGNAL(clicked()), m_renderer, SLOT(setRoundCap()));

            connect(bevelJoin, SIGNAL(clicked()), m_renderer, SLOT(setBevelJoin()));
            connect(miterJoin, SIGNAL(clicked()), m_renderer, SLOT(setMiterJoin()));
            connect(roundJoin, SIGNAL(clicked()), m_renderer, SLOT(setRoundJoin()));

            connect(curveMode, SIGNAL(clicked()), m_renderer, SLOT(setCurveMode()));
            connect(lineMode, SIGNAL(clicked()), m_renderer, SLOT(setLineMode()));

            connect(solidLine, SIGNAL(clicked()), m_renderer, SLOT(setSolidLine()));
            connect(dashLine, SIGNAL(clicked()), m_renderer, SLOT(setDashLine()));
            connect(dotLine, SIGNAL(clicked()), m_renderer, SLOT(setDotLine()));
            connect(dashDotLine, SIGNAL(clicked()), m_renderer, SLOT(setDashDotLine()));
            connect(dashDotDotLine, SIGNAL(clicked()), m_renderer, SLOT(setDashDotDotLine()));
            connect(customDashLine, SIGNAL(clicked()), m_renderer, SLOT(setCustomDashLine()));

            connect(showSourceButton, SIGNAL(clicked()), m_renderer, SLOT(showSource()));

            connect(whatsThisButton, SIGNAL(clicked(bool)), m_renderer, SLOT(setDescriptionEnabled(bool)));
            connect(m_renderer, SIGNAL(descriptionEnabledChanged(bool)),
                    whatsThisButton, SLOT(setChecked(bool)));

            // Set the defaults
            animated->setChecked(true);
            flatCap->setChecked(true);
            bevelJoin->setChecked(true);
            penWidth->setValue(50);
            curveMode->setChecked(true);
            solidLine->setChecked(true);

            m_renderer->loadSourceFile(":res/pathstroke.cpp");
            m_renderer->loadDescription(":res/pathstroke.html");
        }

        PathStrokeRenderer::PathStrokeRenderer(QWidget *parent)
            : ArthurFrame(parent)
        {
            m_pointSize = 10;
            m_activePoint = -1;
            m_capStyle = Qt::FlatCap;
            m_joinStyle = Qt::BevelJoin;
            m_pathMode = CurveMode;
            m_penWidth = 1;
            m_penStyle = Qt::SolidLine;
            m_wasAnimated = true;
            setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
        }

        void PathStrokeRenderer::paint(QPainter *painter)
        {
            if (m_points.isEmpty())
                initializePoints();

            painter->setRenderHint(QPainter::Antialiasing);

            QPalette pal = palette();
            painter->setPen(Qt::NoPen);

            // Construct the path
            QPainterPath path;
            path.moveTo(m_points.at(0));

            if (m_pathMode == LineMode) {
                for (int i=1; i<m_points.size(); ++i) {
                    path.lineTo(m_points.at(i));
                }
            } else {
                int i=1;
                while (i + 2 < m_points.size()) {
                    path.cubicTo(m_points.at(i), m_points.at(i+1), m_points.at(i+2));
                    i += 3;
                }
                while (i < m_points.size()) {
                    path.lineTo(m_points.at(i));
                    ++i;
                }
            }

            // Draw the path
            {
                QColor lg = Qt::red;

                // The "custom" pen
                if (m_penStyle == Qt::NoPen) {
                    QPainterPathStroker stroker;
                    stroker.setWidth(m_penWidth);
                    stroker.setJoinStyle(m_joinStyle);
                    stroker.setCapStyle(m_capStyle);

                    QVector<qreal> dashes;
                    qreal space = 4;
                    dashes << 1 << space
                           << 3 << space
                           << 9 << space
                           << 27 << space
                           << 9 << space
                           << 3 << space;
                    stroker.setDashPattern(dashes);
                    QPainterPath stroke = stroker.createStroke(path);
                    painter->fillPath(stroke, lg);

                } else {
                    QPen pen(lg, m_penWidth, m_penStyle, m_capStyle, m_joinStyle);
                    painter->strokePath(path, pen);
                }
            }

            if (1) {
                // Draw the control points
                painter->setPen(QColor(50, 100, 120, 200));
                painter->setBrush(QColor(200, 200, 210, 120));
                for (int i=0; i<m_points.size(); ++i) {
                    QPointF pos = m_points.at(i);
                    painter->drawEllipse(QRectF(pos.x() - m_pointSize,
                                               pos.y() - m_pointSize,
                                               m_pointSize*2, m_pointSize*2));
                }
                painter->setPen(QPen(Qt::lightGray, 0, Qt::SolidLine));
                painter->setBrush(Qt::NoBrush);
                painter->drawPolyline(m_points);
            }

        }

        void PathStrokeRenderer::initializePoints()
        {
            const int count = 7;
            m_points.clear();
            m_vectors.clear();

            QMatrix m;
            double rot = 360 / count;
            QPointF center(width() / 2, height() / 2);
            QMatrix vm;
            vm.shear(2, -1);
            vm.scale(3, 3);

            for (int i=0; i<count; ++i) {
                m_vectors << QPointF(.1f, .25f) * (m * vm);
                m_points << QPointF(0, 100) * m + center;
                m.rotate(rot);
            }
        }

        void PathStrokeRenderer::updatePoints()
        {
            double pad = 10;
            double left = pad;
            double right = width() - pad;
            double top = pad;
            double bottom = height() - pad;

            Q_ASSERT(m_points.size() == m_vectors.size());
            for (int i=0; i<m_points.size(); ++i) {

                if (i == m_activePoint)
                    continue;

                QPointF pos = m_points.at(i);
                QPointF vec = m_vectors.at(i);
                pos += vec;
                if (pos.x() < left || pos.x() > right) {
                    vec.setX(-vec.x());
                    pos.setX(pos.x() < left ? left : right);
                } if (pos.y() < top || pos.y() > bottom) {
                    vec.setY(-vec.y());
                    pos.setY(pos.y() < top ? top : bottom);
                }
                m_points[i] = pos;
                m_vectors[i] = vec;
            }
            update();
        }

        void PathStrokeRenderer::mousePressEvent(QMouseEvent *e)
        {
            setDescriptionEnabled(false);
            m_activePoint = -1;
            qreal distance = -1;
            for (int i=0; i<m_points.size(); ++i) {
                qreal d = QLineF(e->pos(), m_points.at(i)).length();
                if ((distance < 0 && d < 8 * m_pointSize) || d < distance) {
                    distance = d;
                    m_activePoint = i;
                }
            }

            if (m_activePoint != -1) {
                m_wasAnimated = m_timer.isActive();
                setAnimation(false);
                mouseMoveEvent(e);
            }
        }

        void PathStrokeRenderer::mouseMoveEvent(QMouseEvent *e)
        {
            if (m_activePoint >= 0 && m_activePoint < m_points.size()) {
                m_points[m_activePoint] = e->pos();
                update();
            }
        }

        void PathStrokeRenderer::mouseReleaseEvent(QMouseEvent *)
        {
            m_activePoint = -1;
            setAnimation(m_wasAnimated);
        }

        void PathStrokeRenderer::timerEvent(QTimerEvent *e)
        {
            if (e->timerId() == m_timer.timerId()) {
                updatePoints();
                QApplication::syncX();
            } // else if (e->timerId() == m_fpsTimer.timerId()) {
        //         emit frameRate(m_frameCount);
        //         m_frameCount = 0;
        //     }
        }

        void PathStrokeRenderer::setAnimation(bool animation)
        {
            m_timer.stop();
        //     m_fpsTimer.stop();

            if (animation) {
                m_timer.start(25, this);
        //         m_fpsTimer.start(1000, this);
        //         m_frameCount = 0;
            }
        }