Anchor Layout Example

The Anchor Layout example demonstrates the use of the QGraphicsAnchorLayout class.

The basic steps of this example are:

• Create a QGraphicsScene
• Create widgets
• Create a QGraphicsAnchorLayout
• Create a QGraphicsWidget
• Add vertical and horizontal anchors between the widgets
• View the scene with a QGraphicsView object

Creating a QGraphicsScene

     QGraphicsScene scene;
     scene.setSceneRect(0, 0, 800, 480);

Creating Widgets

     QGraphicsProxyWidget *a = createItem(minSize, prefSize, maxSize, "A");
     QGraphicsProxyWidget *b = createItem(minSize, prefSize, maxSize, "B");
     QGraphicsProxyWidget *c = createItem(minSize, prefSize, maxSize, "C");
     QGraphicsProxyWidget *d = createItem(minSize, prefSize, maxSize, "D");
     QGraphicsProxyWidget *e = createItem(minSize, prefSize, maxSize, "E");
     QGraphicsProxyWidget *f = createItem(QSizeF(30, 50), QSizeF(150, 50), maxSize, "F (overflow)");
     QGraphicsProxyWidget *g = createItem(QSizeF(30, 50), QSizeF(30, 100), maxSize, "G (overflow)");

Creating a Layout

     QGraphicsAnchorLayout *l = new QGraphicsAnchorLayout;
     l->setSpacing(0);

Creating a QGraphicsWidget

     QGraphicsWidget *w = new QGraphicsWidget(nullptr, Qt::Window);
     w->setPos(20, 20);
     w->setLayout(l);

Adding Anchors

     // vertical
     l->addAnchor(a, Qt::AnchorTop, l, Qt::AnchorTop);
     l->addAnchor(b, Qt::AnchorTop, l, Qt::AnchorTop);

     l->addAnchor(c, Qt::AnchorTop, a, Qt::AnchorBottom);
     l->addAnchor(c, Qt::AnchorTop, b, Qt::AnchorBottom);
     l->addAnchor(c, Qt::AnchorBottom, d, Qt::AnchorTop);
     l->addAnchor(c, Qt::AnchorBottom, e, Qt::AnchorTop);

     l->addAnchor(d, Qt::AnchorBottom, l, Qt::AnchorBottom);
     l->addAnchor(e, Qt::AnchorBottom, l, Qt::AnchorBottom);

     l->addAnchor(c, Qt::AnchorTop, f, Qt::AnchorTop);
     l->addAnchor(c, Qt::AnchorVerticalCenter, f, Qt::AnchorBottom);
     l->addAnchor(f, Qt::AnchorBottom, g, Qt::AnchorTop);
     l->addAnchor(c, Qt::AnchorBottom, g, Qt::AnchorBottom);

     // horizontal
     l->addAnchor(l, Qt::AnchorLeft, a, Qt::AnchorLeft);
     l->addAnchor(l, Qt::AnchorLeft, d, Qt::AnchorLeft);
     l->addAnchor(a, Qt::AnchorRight, b, Qt::AnchorLeft);

     l->addAnchor(a, Qt::AnchorRight, c, Qt::AnchorLeft);
     l->addAnchor(c, Qt::AnchorRight, e, Qt::AnchorLeft);

     l->addAnchor(b, Qt::AnchorRight, l, Qt::AnchorRight);
     l->addAnchor(e, Qt::AnchorRight, l, Qt::AnchorRight);
     l->addAnchor(d, Qt::AnchorRight, e, Qt::AnchorLeft);

     l->addAnchor(l, Qt::AnchorLeft, f, Qt::AnchorLeft);
     l->addAnchor(l, Qt::AnchorLeft, g, Qt::AnchorLeft);
     l->addAnchor(f, Qt::AnchorRight, g, Qt::AnchorRight);

Viewing the Scene with QGraphicsView

     scene.addItem(w);
     scene.setBackgroundBrush(Qt::darkGreen);
     QGraphicsView view(&scene);

     view.show();

Example project @ code.qt.io