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 ?

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@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 !

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@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 ;)

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@Walux :-)