Anchor Layout Example

Demonstrates anchor layout in a graphics view scene.

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

See also Simple Anchor Layout Example.

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