Limit connection offsets to reasonable values

editor.cpp

     current_connection_edit_item->setZValue(0);
     setConnectionEditControlsEnabled(true);
     setConnectionEditControlValues(current_connection_edit_item->connection);
+    ui->spinBox_ConnectionOffset->setMaximum(current_connection_edit_item->getMaxOffset());
+    ui->spinBox_ConnectionOffset->setMinimum(current_connection_edit_item->getMinOffset());
 }
 
 void Editor::onConnectionDirectionChanged(QString newDirection) {
     map->connection_items.append(item);
     item->setVisible(!hide);
 
-    ConnectionPixmapItem *connection_edit_item = new ConnectionPixmapItem(pixmap, connection, x, y);
+    ConnectionPixmapItem *connection_edit_item = new ConnectionPixmapItem(pixmap, connection, x, y, map->getWidth(), map->getHeight());
     connection_edit_item->setX(x);
     connection_edit_item->setY(y);
     connection_edit_item->setZValue(-1);
         return;
 
     current_connection_edit_item->blockSignals(true);
+    offset = qMin(offset, current_connection_edit_item->getMaxOffset());
+    offset = qMax(offset, current_connection_edit_item->getMinOffset());
     current_connection_edit_item->connection->offset = QString::number(offset);
     if (current_connection_edit_item->connection->direction == "up" || current_connection_edit_item->connection->direction == "down") {
         current_connection_edit_item->setX(current_connection_edit_item->initialX + (offset - current_connection_edit_item->initialOffset) * 16);
     }
 }
 
+int ConnectionPixmapItem::getMinOffset() {
+    if (connection->direction == "up" || connection->direction == "down")
+        return 1 - (this->pixmap().width() / 16);
+    else
+        return 1 - (this->pixmap().height() / 16);
+}
+int ConnectionPixmapItem::getMaxOffset() {
+    if (connection->direction == "up" || connection->direction == "down")
+        return baseMapWidth - 1;
+    else
+        return baseMapHeight - 1;
+}
 QVariant ConnectionPixmapItem::itemChange(GraphicsItemChange change, const QVariant &value)
 {
     if (change == ItemPositionChange) {
         if (connection->direction == "up" || connection->direction == "down") {
             x = round(newPos.x() / 16) * 16;
             newOffset += (x - initialX) / 16;
+            newOffset = qMin(newOffset, this->getMaxOffset());
+            newOffset = qMax(newOffset, this->getMinOffset());
+            x = newOffset * 16;
         }
         else {
             x = initialX;
         if (connection->direction == "right" || connection->direction == "left") {
             y = round(newPos.y() / 16) * 16;
             newOffset += (y - initialY) / 16;
+            newOffset = qMin(newOffset, this->getMaxOffset());
+            newOffset = qMax(newOffset, this->getMinOffset());
+            y = newOffset * 16;
         }
         else {
             y = initialY;

editor.h

 class ConnectionPixmapItem : public QObject, public QGraphicsPixmapItem {
     Q_OBJECT
 public:
-    ConnectionPixmapItem(QPixmap pixmap, Connection* connection, int x, int y): QGraphicsPixmapItem(pixmap) {
+    ConnectionPixmapItem(QPixmap pixmap, Connection* connection, int x, int y, int baseMapWidth, int baseMapHeight): QGraphicsPixmapItem(pixmap) {
         this->basePixmap = pixmap;
         this->connection = connection;
         setFlag(ItemIsMovable);
         this->initialX = x;
         this->initialY = y;
         this->initialOffset = connection->offset.toInt();
+        this->baseMapWidth = baseMapWidth;
+        this->baseMapHeight = baseMapHeight;
     }
     void render(qreal opacity = 1) {
         QPixmap newPixmap = basePixmap.copy(0, 0, basePixmap.width(), basePixmap.height());
         }
         this->setPixmap(newPixmap);
     }
+    int getMinOffset();
+    int getMaxOffset();
     QPixmap basePixmap;
     Connection* connection;
     int initialX;
     int initialY;
     int initialOffset;
+    int baseMapWidth;
+    int baseMapHeight;
 protected:
     QVariant itemChange(GraphicsItemChange change, const QVariant &value);
     void mousePressEvent(QGraphicsSceneMouseEvent*);