document.cpp Example File
^{demos/undo/document.cpp}

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 #include <math.h>
 #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();
 }