[Solved] QGraphicsScene/View displays empty rect

Woomla

Hi,

If I add a rect to a QGraphicsScene with a zero height, the rect is still displayed on the QGraphicsView.

!http://i42.tinypic.com/2pt8dg5.jpg!

Created with:

@QMatrix matrix;
matrix.scale(8, -8);
graphicsView.setMatrix(matrix);

scene.addRect(0, 0, 10, 5, QPen(QColor("yellow"), 1));
scene.addRect(0, 0, 1, 0, QPen(QColor("red"), 1));
scene.addRect(5, 0, 5, 0, QPen(QColor("blue"), 0), QBrush(QColor("green"), Qt::NoBrush));
@

The complete source file is here: "Empty Rect Example":http://pastebin.com/64tkStUe

What can I do to make this (red and blue) rect to not display anything but still be there?

Asperamanca

The pen specifies the border of the rectangle. Basically, a rectangle of height zero behaves like a line, so it's logical that something will be painted.

Use a Brush instead of a Pen to fill the interior of the rectangle instead of painting the border. A rectangle with height zero should have no interior, and therefore not draw
You can always write your own rectangle item that behaves exactly as you want...

Woomla

Great!

I've changed line 5,6 and 7 to:

@
scene.addRect(0, 0, 10, 5, QPen(QBrush(Qt::NoBrush), 0), QBrush(QColor("yellow")));
scene.addRect(0, 0, 1, 0, QPen(QBrush(Qt::NoBrush), 0), QBrush(QColor("#red")));
scene.addRect(5, 0, 5, 0, QPen(QBrush(Qt::NoBrush), 0), QBrush(QColor("#blue")));
@

Asperamanca

I think you can simplify to

@scene.addRect(0, 0, 10, 5, QPen(Qt::NoPen), QBrush(QColor("yellow")));@

Woomla

Cool! Tx.

And of course '#red' should be just 'red'.