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# document.cpp Example File

demos/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.
     **
     ** $QT_BEGIN_LICENSE:LGPL$
     ** 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.
     **
     ** GNU General Public License Usage
     ** Alternatively, this file may be used under the terms of the GNU
     ** General Public License version 3.0 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 the GNU General Public License version 3.0 requirements will be
     ** met: http://www.gnu.org/copyleft/gpl.html.
     **
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #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();
     }