Qt 5.6 | Qt Widgets | Undo Framework | document.cpp Example File

Qt 5.6.2 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
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      ** 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.
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      ** $QT_END_LICENSE$
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      ****************************************************************************/

      #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();
      }