- Qt 5.5
- Qt Widgets
- Undo Framework
- document.cpp Example File
- Qt 5.5.1 Reference Documentation

# document.cpp Example File

tools/undo/document.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the demonstration applications of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:LGPL21$
    ** Commercial License Usage
    ** Licensees holding valid commercial Qt licenses may use this file in
    ** accordance with the commercial license agreement provided with the
    ** Software or, alternatively, in accordance with the terms contained in
    ** a written agreement between you and The Qt Company. For licensing terms
    ** and conditions see http://www.qt.io/terms-conditions. For further
    ** information use the contact form at http://www.qt.io/contact-us.
    **
    ** GNU Lesser General Public License Usage
    ** Alternatively, this file may be used under the terms of the GNU Lesser
    ** General Public License version 2.1 or version 3 as published by the Free
    ** Software Foundation and appearing in the file LICENSE.LGPLv21 and
    ** LICENSE.LGPLv3 included in the packaging of this file. Please review the
    ** following information to ensure the GNU Lesser General Public License
    ** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
    ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
    **
    ** As a special exception, The Qt Company gives you certain additional
    ** rights. These rights are described in The Qt Company LGPL Exception
    ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
    **
    ** $QT_END_LICENSE$
    **
    ****************************************************************************/

    #include <qevent.h>
    #include <QPainter>
    #include <QTextStream>
    #include <QUndoStack>
    #include "document.h"
    #include "commands.h"

    static const int resizeHandleWidth = 6;

    /******************************************************************************
    ** Shape
    */

    const QSize Shape::minSize(80, 50);

    Shape::Shape(Type type, const QColor &color, const QRect &rect)
        : m_type(type), m_rect(rect), m_color(color)
    {
    }

    Shape::Type Shape::type() const
    {
        return m_type;
    }

    QRect Shape::rect() const
    {
        return m_rect;
    }

    QColor Shape::color() const
    {
        return m_color;
    }

    QString Shape::name() const
    {
        return m_name;
    }

    QRect Shape::resizeHandle() const
    {
        QPoint br = m_rect.bottomRight();
        return QRect(br - QPoint(resizeHandleWidth, resizeHandleWidth), br);
    }

    QString Shape::typeToString(Type type)
    {
        QString result;

        switch (type) {
            case Rectangle:
                result = QLatin1String("Rectangle");
                break;
            case Circle:
                result = QLatin1String("Circle");
                break;
            case Triangle:
                result = QLatin1String("Triangle");
                break;
        }

        return result;
    }

    Shape::Type Shape::stringToType(const QString &s, bool *ok)
    {
        if (ok != 0)
            *ok = true;

        if (s == QLatin1String("Rectangle"))
            return Rectangle;
        if (s == QLatin1String("Circle"))
            return Circle;
        if (s == QLatin1String("Triangle"))
            return Triangle;

        if (ok != 0)
            *ok = false;
        return Rectangle;
    }

    /******************************************************************************
    ** Document
    */

    Document::Document(QWidget *parent)
        : QWidget(parent), m_currentIndex(-1), m_mousePressIndex(-1), m_resizeHandlePressed(false)
    {
        m_undoStack = new QUndoStack(this);

        setAutoFillBackground(true);
        setBackgroundRole(QPalette::Base);

        QPalette pal = palette();
        pal.setBrush(QPalette::Base, QPixmap(":/icons/background.png"));
        pal.setColor(QPalette::HighlightedText, Qt::red);
        setPalette(pal);
    }

    QString Document::addShape(const Shape &shape)
    {
        QString name = Shape::typeToString(shape.type());
        name = uniqueName(name);

        m_shapeList.append(shape);
        m_shapeList[m_shapeList.count() - 1].m_name = name;
        setCurrentShape(m_shapeList.count() - 1);

        return name;
    }

    void Document::deleteShape(const QString &shapeName)
    {
        int index = indexOf(shapeName);
        if (index == -1)
            return;

        update(m_shapeList.at(index).rect());

        m_shapeList.removeAt(index);

        if (index <= m_currentIndex) {
            m_currentIndex = -1;
            if (index == m_shapeList.count())
                --index;
            setCurrentShape(index);
        }
    }

    Shape Document::shape(const QString &shapeName) const
    {
        int index = indexOf(shapeName);
        if (index == -1)
            return Shape();
        return m_shapeList.at(index);
    }

    void Document::setShapeRect(const QString &shapeName, const QRect &rect)
    {
        int index = indexOf(shapeName);
        if (index == -1)
            return;

        Shape &shape = m_shapeList[index];

        update(shape.rect());
        update(rect);

        shape.m_rect = rect;
    }

    void Document::setShapeColor(const QString &shapeName, const QColor &color)
    {

        int index = indexOf(shapeName);
        if (index == -1)
            return;

        Shape &shape = m_shapeList[index];
        shape.m_color = color;

        update(shape.rect());
    }

    QUndoStack *Document::undoStack() const
    {
        return m_undoStack;
    }

    bool Document::load(QTextStream &stream)
    {
        m_shapeList.clear();

        while (!stream.atEnd()) {
            QString shapeType, shapeName, colorName;
            int left, top, width, height;
            stream >> shapeType >> shapeName >> colorName >> left >> top >> width >> height;
            if (stream.status() != QTextStream::Ok)
                return false;
            bool ok;
            Shape::Type type = Shape::stringToType(shapeType, &ok);
            if (!ok)
                return false;
            QColor color(colorName);
            if (!color.isValid())
                return false;

            Shape shape(type);
            shape.m_name = shapeName;
            shape.m_color = color;
            shape.m_rect = QRect(left, top, width, height);

            m_shapeList.append(shape);
        }

        m_currentIndex = m_shapeList.isEmpty() ? -1 : 0;

        return true;
    }

    void Document::save(QTextStream &stream)
    {
        for (int i = 0; i < m_shapeList.count(); ++i) {
            const Shape &shape = m_shapeList.at(i);
            QRect r = shape.rect();
            stream << Shape::typeToString(shape.type()) << QLatin1Char(' ')
                    << shape.name() << QLatin1Char(' ')
                    << shape.color().name() << QLatin1Char(' ')
                    << r.left() << QLatin1Char(' ')
                    << r.top() << QLatin1Char(' ')
                    << r.width() << QLatin1Char(' ')
                    << r.height();
            if (i != m_shapeList.count() - 1)
                stream << QLatin1Char('\n');
        }
        m_undoStack->setClean();
    }

    QString Document::fileName() const
    {
        return m_fileName;
    }

    void Document::setFileName(const QString &fileName)
    {
        m_fileName = fileName;
    }

    int Document::indexAt(const QPoint &pos) const
    {
        for (int i = m_shapeList.count() - 1; i >= 0; --i) {
            if (m_shapeList.at(i).rect().contains(pos))
                return i;
        }
        return -1;
    }

    void Document::mousePressEvent(QMouseEvent *event)
    {
        event->accept();
        int index = indexAt(event->pos());;
        if (index != -1) {
            setCurrentShape(index);

            const Shape &shape = m_shapeList.at(index);
            m_resizeHandlePressed = shape.resizeHandle().contains(event->pos());

            if (m_resizeHandlePressed)
                m_mousePressOffset = shape.rect().bottomRight() - event->pos();
            else
                m_mousePressOffset = event->pos() - shape.rect().topLeft();
        }
        m_mousePressIndex = index;
    }

    void Document::mouseReleaseEvent(QMouseEvent *event)
    {
        event->accept();
        m_mousePressIndex = -1;
    }

    void Document::mouseMoveEvent(QMouseEvent *event)
    {
        event->accept();

        if (m_mousePressIndex == -1)
            return;

        const Shape &shape = m_shapeList.at(m_mousePressIndex);

        QRect rect;
        if (m_resizeHandlePressed) {
            rect = QRect(shape.rect().topLeft(), event->pos() + m_mousePressOffset);
        } else {
            rect = shape.rect();
            rect.moveTopLeft(event->pos() - m_mousePressOffset);
        }

        QSize size = rect.size().expandedTo(Shape::minSize);
        rect.setSize(size);

        m_undoStack->push(new SetShapeRectCommand(this, shape.name(), rect));
    }

    static QGradient gradient(const QColor &color, const QRect &rect)
    {
        QColor c = color;
        c.setAlpha(160);
        QLinearGradient result(rect.topLeft(), rect.bottomRight());
        result.setColorAt(0, c.dark(150));
        result.setColorAt(0.5, c.light(200));
        result.setColorAt(1, c.dark(150));
        return result;
    }

    static QPolygon triangle(const QRect &rect)
    {
        QPolygon result(3);
        result.setPoint(0, rect.center().x(), rect.top());
        result.setPoint(1, rect.right(), rect.bottom());
        result.setPoint(2, rect.left(), rect.bottom());
        return result;
    }

    void Document::paintEvent(QPaintEvent *event)
    {
        QRegion paintRegion = event->region();
        QPainter painter(this);
        QPalette pal = palette();

        for (int i = 0; i < m_shapeList.count(); ++i) {
            const Shape &shape = m_shapeList.at(i);

            if (!paintRegion.contains(shape.rect()))
                continue;

            QPen pen = pal.text().color();
            pen.setWidth(i == m_currentIndex ? 2 : 1);
            painter.setPen(pen);
            painter.setBrush(gradient(shape.color(), shape.rect()));

            QRect rect = shape.rect();
            rect.adjust(1, 1, -resizeHandleWidth/2, -resizeHandleWidth/2);

            // paint the shape
            switch (shape.type()) {
                case Shape::Rectangle:
                    painter.drawRect(rect);
                    break;
                case Shape::Circle:
                    painter.setRenderHint(QPainter::Antialiasing);
                    painter.drawEllipse(rect);
                    painter.setRenderHint(QPainter::Antialiasing, false);
                    break;
                case Shape::Triangle:
                    painter.setRenderHint(QPainter::Antialiasing);
                    painter.drawPolygon(triangle(rect));
                    painter.setRenderHint(QPainter::Antialiasing, false);
                    break;
            }

            // paint the resize handle
            painter.setPen(pal.text().color());
            painter.setBrush(Qt::white);
            painter.drawRect(shape.resizeHandle().adjusted(0, 0, -1, -1));

            // paint the shape name
            painter.setBrush(pal.text());
            if (shape.type() == Shape::Triangle)
                rect.adjust(0, rect.height()/2, 0, 0);
            painter.drawText(rect, Qt::AlignCenter, shape.name());
        }
    }

    void Document::setCurrentShape(int index)
    {
        QString currentName;

        if (m_currentIndex != -1)
            update(m_shapeList.at(m_currentIndex).rect());

        m_currentIndex = index;

        if (m_currentIndex != -1) {
            const Shape &current = m_shapeList.at(m_currentIndex);
            update(current.rect());
            currentName = current.name();
        }

        emit currentShapeChanged(currentName);
    }

    int Document::indexOf(const QString &shapeName) const
    {
        for (int i = 0; i < m_shapeList.count(); ++i) {
            if (m_shapeList.at(i).name() == shapeName)
                return i;
        }
        return -1;
    }

    QString Document::uniqueName(const QString &name) const
    {
        QString unique;

        for (int i = 0; ; ++i) {
            unique = name;
            if (i > 0)
                unique += QString::number(i);
            if (indexOf(unique) == -1)
                break;
        }

        return unique;
    }

    QString Document::currentShapeName() const
    {
        if (m_currentIndex == -1)
            return QString();
        return m_shapeList.at(m_currentIndex).name();
    }