How to draw rounded live using QT

[CorD SaC]

How can I design rounded line like this image.I need to design a rounded line when the button click.

void MainWindow::on_btnCreateRoundedLine_clicked()
{

}

[koahnig]

@CorD-SaC

Possibly as part of an ellipse

[CorD SaC]

@koahnig Can you provide me sample code please

[mrjj]

@CorD-SaC
Can you provide at little bit more information ?
Are you using QGraphicsView or QPainter ?
Where do you want to draw it ?
You cannot just paint in on_btnCreateRoundedLine_clicked
as all painting must be done in paintEvent function.
You could paint on a pixmap and use a QLabel to display it.

Also what you are showing is not really a line with round edge but
more of a spline type.

A very fast way would be to use drawing program like inkscape and simply load
it as a SVG image into a QLabel.

But it all really depends on what you are trying to do.

[CorD SaC]

@mrjj I tried it like this problem solved.now I need to change the color of this shape when I select color from color dialog or another way,and also I need to rotate this Item.how can I do this?

This is my code.

void Widget::on_pushButton_clicked()
{
    QPainterPath path;
    path.moveTo(10, 20);
    path.lineTo(10, 40);
    path.arcTo(QRectF(10, 20, 40, 40), 180, 180);
    path.moveTo(50, 40);
    path.lineTo(50, 20);
    QPen redPen(Qt::red);
    redPen.setWidth(2);
    QGraphicsPathItem* item = ui->graphicsView->scene()->addPath(path, redPen);
    /*
        QGraphicsPathItem* item = new QGraphicsPathItem(path);
        item->setPen(redPen);
    */

    item->setFlag(QGraphicsItem::ItemIsMovable, true);
    item->setFlag(QGraphicsItem::ItemIsSelectable,true);
}

[mrjj]

• now I need to change the color of this shape

You can just do it
http://doc.qt.io/qt-5/qabstractgraphicsshapeitem.html#setPen

[CorD SaC]

@mrjj said in How to draw rounded live using QT:

can just do it

I solved rotate item problem. now I need to change color of this item.according to your answer I already use setPen method. But how can I change the color of this Item when I select color from color dialog.

[koahnig]

@CorD-SaC

How about this method setColor?

[CorD SaC]

@koahnig Can You give some sample code.How can I pick color from QColorDialog and assign that color to this curve shape

[koahnig]

@CorD-SaC

There is this example in the document database