QPainter trick .

[Walux]

Hi Qt Community ,

I tried countless times to create a certain shape but i failed :

I want to draw a "donut"-like shape whose center is transparent , so i tried something like this , but it was in vain :

painter->setBrush(MyColor);
painter->drawEllipse(QPointF(0,0),10,10);
painter->setBrush(Qt::NoBrush);
painter->drawEllipse(QPointF(0,0),6,6);

Any ideas ?

[A Former User]

@Walux said:

Any ideas ?

    QPainterPath path;
    path.addEllipse(0, 0, 400, 400);
    path.addEllipse(50,50,300,300);
    painter->setRenderHint(QPainter::Antialiasing);
    painter->setBrush( QBrush(QColor("black")) );
    painter->drawPath(path);

[Walux]

@Wieland

Works like a charm !
I wonder why this worked !

[A Former User]

@Walux said:

I wonder why this worked

See QPainterPath Class, especially note:

Finally we draw the entire path. The path is filled using the default fill rule, Qt::OddEvenFill.

Qt::OddEvenFill

Specifies that the region is filled using the odd even fill rule. With this rule, we determine whether a point is inside the shape by using the following method. Draw a horizontal line from the point to a location outside the shape, and count the number of intersections. If the number of intersections is an odd number, the point is inside the shape. This mode is the default.

[Walux]

@Wieland

Very informative :)
U have my precious thanks ;)

[A Former User]

@Walux :-)