piecesmodel.cpp Example File

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  #include "piecesmodel.h"

  #include <QIcon>
  #include <QMimeData>

  PiecesModel::PiecesModel(int pieceSize, QObject *parent)
      : QAbstractListModel(parent), m_PieceSize(pieceSize)
  {
  }

  QVariant PiecesModel::data(const QModelIndex &index, int role) const
  {
      if (!index.isValid())
          return QVariant();

      if (role == Qt::DecorationRole)
          return QIcon(pixmaps.value(index.row()).scaled(m_PieceSize, m_PieceSize,
                           Qt::KeepAspectRatio, Qt::SmoothTransformation));
      else if (role == Qt::UserRole)
          return pixmaps.value(index.row());
      else if (role == Qt::UserRole + 1)
          return locations.value(index.row());

      return QVariant();
  }

  void PiecesModel::addPiece(const QPixmap &pixmap, const QPoint &location)
  {
      int row;
      if (int(2.0 * qrand() / (RAND_MAX + 1.0)) == 1)
          row = 0;
      else
          row = pixmaps.size();

      beginInsertRows(QModelIndex(), row, row);
      pixmaps.insert(row, pixmap);
      locations.insert(row, location);
      endInsertRows();
  }

  Qt::ItemFlags PiecesModel::flags(const QModelIndex &index) const
  {
      if (index.isValid())
          return (QAbstractListModel::flags(index)|Qt::ItemIsDragEnabled);

      return Qt::ItemIsDropEnabled;
  }

  bool PiecesModel::removeRows(int row, int count, const QModelIndex &parent)
  {
      if (parent.isValid())
          return false;

      if (row >= pixmaps.size() || row + count <= 0)
          return false;

      int beginRow = qMax(0, row);
      int endRow = qMin(row + count - 1, pixmaps.size() - 1);

      beginRemoveRows(parent, beginRow, endRow);

      while (beginRow <= endRow) {
          pixmaps.removeAt(beginRow);
          locations.removeAt(beginRow);
          ++beginRow;
      }

      endRemoveRows();
      return true;
  }

  QStringList PiecesModel::mimeTypes() const
  {
      QStringList types;
      types << "image/x-puzzle-piece";
      return types;
  }

  QMimeData *PiecesModel::mimeData(const QModelIndexList &indexes) const
  {
      QMimeData *mimeData = new QMimeData();
      QByteArray encodedData;

      QDataStream stream(&encodedData, QIODevice::WriteOnly);

      foreach (QModelIndex index, indexes) {
          if (index.isValid()) {
              QPixmap pixmap = qvariant_cast<QPixmap>(data(index, Qt::UserRole));
              QPoint location = data(index, Qt::UserRole+1).toPoint();
              stream << pixmap << location;
          }
      }

      mimeData->setData("image/x-puzzle-piece", encodedData);
      return mimeData;
  }

  bool PiecesModel::dropMimeData(const QMimeData *data, Qt::DropAction action,
                                 int row, int column, const QModelIndex &parent)
  {
      if (!data->hasFormat("image/x-puzzle-piece"))
          return false;

      if (action == Qt::IgnoreAction)
          return true;

      if (column > 0)
          return false;

      int endRow;

      if (!parent.isValid()) {
          if (row < 0)
              endRow = pixmaps.size();
          else
              endRow = qMin(row, pixmaps.size());
      } else {
          endRow = parent.row();
      }

      QByteArray encodedData = data->data("image/x-puzzle-piece");
      QDataStream stream(&encodedData, QIODevice::ReadOnly);

      while (!stream.atEnd()) {
          QPixmap pixmap;
          QPoint location;
          stream >> pixmap >> location;

          beginInsertRows(QModelIndex(), endRow, endRow);
          pixmaps.insert(endRow, pixmap);
          locations.insert(endRow, location);
          endInsertRows();

          ++endRow;
      }

      return true;
  }

  int PiecesModel::rowCount(const QModelIndex &parent) const
  {
      if (parent.isValid())
          return 0;
      else
          return pixmaps.size();
  }

  Qt::DropActions PiecesModel::supportedDropActions() const
  {
      return Qt::CopyAction | Qt::MoveAction;
  }

  void PiecesModel::addPieces(const QPixmap& pixmap)
  {
      beginRemoveRows(QModelIndex(), 0, 24);
      pixmaps.clear();
      locations.clear();
      endRemoveRows();
      for (int y = 0; y < 5; ++y) {
          for (int x = 0; x < 5; ++x) {
              QPixmap pieceImage = pixmap.copy(x*m_PieceSize, y*m_PieceSize, m_PieceSize, m_PieceSize);
              addPiece(pieceImage, QPoint(x, y));
          }
      }
  }