Qt 5.11 | Qt Widgets | Item Views Puzzle Example | piecesmodel.cpp Example File

Qt 5.11.3 Reference Documentation

# piecesmodel.cpp Example File

itemviews/puzzle/piecesmodel.cpp

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      #include "piecesmodel.h"

      #include <QIcon>
      #include <QMimeData>
      #include <QRandomGenerator>

      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 (QRandomGenerator::global()->bounded(2) == 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)
      {
          if (!pixmaps.isEmpty()) {
              beginRemoveRows(QModelIndex(), 0, pixmaps.size() - 1);
              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));
              }
          }
      }