- Qt 6.9
- Qt Widgets
- Simple Anchor Layout Example
- Qt 6.9.0 Reference Documentation

# Simple Anchor Layout Example

Demonstrates anchor layout on a graphics view scene.

The Simple Anchor Layout example shows the basic use of the QGraphicsAnchorLayout class.

The example starts by creating a QGraphicsScene (`scene`), 3 widgets (`a`, `b`, and `c`), and a QGraphicsAnchorlayout (`layout`).

         QGraphicsScene scene;

         Widget *a = new Widget(Qt::blue, Qt::white, "a");
         a->setPreferredSize(100, 100);
         Widget *b = new Widget(Qt::green, Qt::black, "b");
         b->setPreferredSize(100, 100);
         Widget *c = new Widget(Qt::red, Qt::black, "c");
         c->setPreferredSize(100, 100);

         QGraphicsAnchorLayout *layout = new QGraphicsAnchorLayout;

First it anchors the top left corner of item `a` to the top left corner of `layout`. This can be done in two steps:

         layout->addAnchor(a, Qt::AnchorTop, layout, Qt::AnchorTop);
         layout->addAnchor(a, Qt::AnchorLeft, layout, Qt::AnchorLeft);

Or in one step:

         layout->addCornerAnchors(a, Qt::TopLeftCorner, layout, Qt::TopLeftCorner);

Then the right anchor of `a` is anchored to the left anchor of `b`, and the top of item `b` is anchored to the bottom of `a`.

         layout->addAnchor(b, Qt::AnchorLeft, a, Qt::AnchorRight);
         layout->addAnchor(b, Qt::AnchorTop, a, Qt::AnchorBottom);

Place a third widget `c` under widget `b`:

         layout->addAnchor(b, Qt::AnchorBottom, c, Qt::AnchorTop);

Items `b` and `c` are anchored to each other horizontally:

         layout->addAnchors(b, c, Qt::Horizontal);

Item c is anchored to the bottom right point of `layout`

         layout->addCornerAnchors(c, Qt::BottomRightCorner, layout, Qt::BottomRightCorner);

Finally, QGraphicsWidget `w` is displayed in QGraphicsView `view`.

         auto w = new QGraphicsWidget(nullptr, Qt::Window | Qt::CustomizeWindowHint | Qt::WindowTitleHint);
         w->setPos(20, 20);
         w->setMinimumSize(100, 100);
         w->setPreferredSize(320, 240);
         w->setLayout(layout);
         w->setWindowTitle(QApplication::translate("simpleanchorlayout", "QGraphicsAnchorLayout in use"));
         scene.addItem(w);

         QGraphicsView view;
         view.setScene(&scene);
         view.setWindowTitle(QApplication::translate("simpleanchorlayout", "Simple Anchor Layout"));

         view.resize(360, 320);
         view.show();

         return app.exec();

Example project @ code.qt.io