Square drawn at the end of a dashed line.

#include <QApplication>
#include <QMainWindow>
#include <QGraphicsScene>
#include <QGraphicsView>
#include <QGraphicsLineItem>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QMainWindow w;

    QGraphicsScene* scene = new QGraphicsScene(&w);
    QGraphicsView* view = new QGraphicsView(scene);

    w.setCentralWidget(view);

    QGraphicsLineItem* line = new QGraphicsLineItem(0, 0, 120, 90);
    QPen pen;
    pen.setStyle(Qt::DashLine);
    line->setPen(pen);
    scene->addItem(line);

    // The problem occurs only with some scaling factors
    // 3.160913184460621305760241739335469901561737060546875 is one of them
    // Many others can be found, for example by successively
    // calling view->scale(1.01, 1.01)
    qreal f = 3.160913184460621305760241739335469901561737060546875;
    view->scale(f, f);

    w.setMinimumSize(700, 700);
    w.show();
    return a.exec();
}