puzzlewidget.cpp Example File

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  #include "puzzlewidget.h"
  #include "pieceslist.h"

  #include <QDrag>
  #include <QDragEnterEvent>
  #include <QMimeData>
  #include <QPainter>

  PuzzleWidget::PuzzleWidget(int imageSize, QWidget *parent)
      : QWidget(parent), m_ImageSize(imageSize)
  {
      setAcceptDrops(true);
      setMinimumSize(m_ImageSize, m_ImageSize);
      setMaximumSize(m_ImageSize, m_ImageSize);
  }

  void PuzzleWidget::clear()
  {
      pieceLocations.clear();
      piecePixmaps.clear();
      pieceRects.clear();
      highlightedRect = QRect();
      inPlace = 0;
      update();
  }

  void PuzzleWidget::dragEnterEvent(QDragEnterEvent *event)
  {
      if (event->mimeData()->hasFormat(PiecesList::puzzleMimeType()))
          event->accept();
      else
          event->ignore();
  }

  void PuzzleWidget::dragLeaveEvent(QDragLeaveEvent *event)
  {
      QRect updateRect = highlightedRect;
      highlightedRect = QRect();
      update(updateRect);
      event->accept();
  }

  void PuzzleWidget::dragMoveEvent(QDragMoveEvent *event)
  {
      QRect updateRect = highlightedRect.united(targetSquare(event->pos()));

      if (event->mimeData()->hasFormat(PiecesList::puzzleMimeType())
          && pieceRects.indexOf(targetSquare(event->pos())) == -1) {

          highlightedRect = targetSquare(event->pos());
          event->setDropAction(Qt::MoveAction);
          event->accept();
      } else {
          highlightedRect = QRect();
          event->ignore();
      }

      update(updateRect);
  }

  void PuzzleWidget::dropEvent(QDropEvent *event)
  {
      if (event->mimeData()->hasFormat(PiecesList::puzzleMimeType())
          && pieceRects.indexOf(targetSquare(event->pos())) == -1) {

          QByteArray pieceData = event->mimeData()->data(PiecesList::puzzleMimeType());
          QDataStream dataStream(&pieceData, QIODevice::ReadOnly);
          QRect square = targetSquare(event->pos());
          QPixmap pixmap;
          QPoint location;
          dataStream >> pixmap >> location;

          pieceLocations.append(location);
          piecePixmaps.append(pixmap);
          pieceRects.append(square);

          highlightedRect = QRect();
          update(square);

          event->setDropAction(Qt::MoveAction);
          event->accept();

          if (location == QPoint(square.x()/pieceSize(), square.y()/pieceSize())) {
              inPlace++;
              if (inPlace == 25)
                  emit puzzleCompleted();
          }
      } else {
          highlightedRect = QRect();
          event->ignore();
      }
  }

  void PuzzleWidget::mousePressEvent(QMouseEvent *event)
  {
      QRect square = targetSquare(event->pos());
      int found = pieceRects.indexOf(square);

      if (found == -1)
          return;

      QPoint location = pieceLocations[found];
      QPixmap pixmap = piecePixmaps[found];
      pieceLocations.removeAt(found);
      piecePixmaps.removeAt(found);
      pieceRects.removeAt(found);

      if (location == QPoint(square.x()/pieceSize(), square.y()/pieceSize()))
          inPlace--;

      update(square);

      QByteArray itemData;
      QDataStream dataStream(&itemData, QIODevice::WriteOnly);

      dataStream << pixmap << location;

      QMimeData *mimeData = new QMimeData;
      mimeData->setData(PiecesList::puzzleMimeType(), itemData);

      QDrag *drag = new QDrag(this);
      drag->setMimeData(mimeData);
      drag->setHotSpot(event->pos() - square.topLeft());
      drag->setPixmap(pixmap);

      if (!(drag->exec(Qt::MoveAction) == Qt::MoveAction)) {
          pieceLocations.insert(found, location);
          piecePixmaps.insert(found, pixmap);
          pieceRects.insert(found, square);
          update(targetSquare(event->pos()));

          if (location == QPoint(square.x()/pieceSize(), square.y()/pieceSize()))
              inPlace++;
      }
  }

  void PuzzleWidget::paintEvent(QPaintEvent *event)
  {
      QPainter painter;
      painter.begin(this);
      painter.fillRect(event->rect(), Qt::white);

      if (highlightedRect.isValid()) {
          painter.setBrush(QColor("#ffcccc"));
          painter.setPen(Qt::NoPen);
          painter.drawRect(highlightedRect.adjusted(0, 0, -1, -1));
      }

      for (int i = 0; i < pieceRects.size(); ++i)
          painter.drawPixmap(pieceRects[i], piecePixmaps[i]);
      painter.end();
  }

  const QRect PuzzleWidget::targetSquare(const QPoint &position) const
  {
      return QRect(position.x()/pieceSize() * pieceSize(), position.y()/pieceSize() * pieceSize(), pieceSize(), pieceSize());
  }

  int PuzzleWidget::pieceSize() const
  {
      return m_ImageSize / 5;
  }

  int PuzzleWidget::imageSize() const
  {
      return m_ImageSize;
  }