在Qt中的QGraphicsScene中绘画

Question

I am trying to paint a line in a QGraphicsScene . I know how to add items in a scene but not how to add items in the scene that are drawn using painter. Below is the code I am trying to implement:

void MainWindow::drawLine(){
    painter->drawLine(100,10,200,20);
    item = ??
    scene->addItem(item);
    ui->graphicsView->setScene(scene);
    qDebug() << "Line Created";
}

As you may see, the item is not defined above. How to create an item for the same so that it is painted in the scene?

Answer 1

You should inherit from QGraphicsItem and override the paint method. I found a nice tutorial regarding it: tutorial.

Keep in mind that in your inherited item, you must implement at least the two pure virtual methods paint and boundingRect . You can see that these functions are pure virtual by looking in the documentation of QGraphicsItem : QGraphicsItem.