Qt 4.3: diagramitem.cpp Example File (graphicsview/diagramscene/diagramitem.cpp)

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# diagramitem.cpp Example File
graphicsview/diagramscene/diagramitem.cpp

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     #include <QtGui>

     #include "diagramitem.h"
     #include "arrow.h"

     DiagramItem::DiagramItem(DiagramType diagramType, QMenu *contextMenu,
                  QGraphicsItem *parent, QGraphicsScene *scene)
         : QGraphicsPolygonItem(parent, scene)
     {
         myDiagramType = diagramType;
         myContextMenu = contextMenu;

         QPainterPath path;
         switch (myDiagramType) {
             case StartEnd:
                 path.moveTo(200, 50);
                 path.arcTo(150, 0, 50, 50, 0, 90);
                 path.arcTo(50, 0, 50, 50, 90, 90);
                 path.arcTo(50, 50, 50, 50, 180, 90);
                 path.arcTo(150, 50, 50, 50, 270, 90);
                 path.lineTo(200, 25);
                 myPolygon = path.toFillPolygon();
                 break;
             case Conditional:
                 myPolygon << QPointF(-100, 0) << QPointF(0, 100)
                           << QPointF(100, 0) << QPointF(0, -100)
                           << QPointF(-100, 0);
                 break;
             case Step:
                 myPolygon << QPointF(-100, -100) << QPointF(100, -100)
                           << QPointF(100, 100) << QPointF(-100, 100)
                           << QPointF(-100, -100);
                 break;
             default:
                 myPolygon << QPointF(-120, -80) << QPointF(-70, 80)
                           << QPointF(120, 80) << QPointF(70, -80)
                           << QPointF(-120, -80);
                 break;
         }
         setPolygon(myPolygon);
         setFlag(QGraphicsItem::ItemIsMovable, true);
         setFlag(QGraphicsItem::ItemIsSelectable, true);
     }

     void DiagramItem::removeArrow(Arrow *arrow)
     {
         int index = arrows.indexOf(arrow);

         if (index != -1)
             arrows.removeAt(index);
     }

     void DiagramItem::removeArrows()
     {
         foreach (Arrow *arrow, arrows) {
             arrow->startItem()->removeArrow(arrow);
             arrow->endItem()->removeArrow(arrow);
             scene()->removeItem(arrow);
             delete arrow;
         }
     }

     void DiagramItem::addArrow(Arrow *arrow)
     {
         arrows.append(arrow);
     }

     QPixmap DiagramItem::image() const
     {
         QPixmap pixmap(250, 250);
         pixmap.fill(Qt::transparent);
         QPainter painter(&pixmap);
         painter.setPen(QPen(Qt::black, 8));
         painter.translate(125, 125);
         painter.drawPolyline(myPolygon);

         return pixmap;
     }

     void DiagramItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event)
     {
         scene()->clearSelection();
         setSelected(true);
         myContextMenu->exec(event->screenPos());
     }

     QVariant DiagramItem::itemChange(GraphicsItemChange change,
                          const QVariant &value)
     {
         if (change == QGraphicsItem::ItemPositionChange) {
             foreach (Arrow *arrow, arrows) {
                 arrow->updatePosition();
             }
         }

         return value;
     }