use painter in QGraphicsScene::drawForeground

[jano_alex_es]

Hi,

I want to draw a QRectF on my graphicsScene, but I don't know why it doesn't work.

void myScene::drawBackground ( QPainter * painter, const QRectF & rect )
{
        QRectF rec(m_startRectPoint, getCursorScenePos/*this function works perfectly*/()); 
		painter->setPen(QPen(Qt::black, 1, Qt::DashLine));
		painter->drawRect(rec);
                update();
 
	//QGraphicsScene::drawForeground(painter, rect);
	QGraphicsScene::drawBackground(painter, rect);
}

void myScene::drawBackground ( QPainter * painter, const QRectF & rect )
{
        QRectF rec(m_startRectPoint, getCursorScenePos/*this function works perfectly*/()); 
		painter->setPen(QPen(Qt::black, 1, Qt::DashLine));
		painter->drawRect(rec);
                update();

	//QGraphicsScene::drawForeground(painter, rect);
	QGraphicsScene::drawBackground(painter, rect);
}

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I want to draw a rectangle which starts in "m_startREctPoint" and finishes in the mouse pointer, at each moment (I did similar things using paint event in the QGraphicsItems).
Am I doing something wrong there?

EDIT: I forgot to say something, if you minimize and maximize the widow it paints it well, as expected.

thanks!

[alpinista]

Hi ..

I want just ask: How do you force the scene to call your drawBackground() method? It seems that it isn't called when you move the mouse. Have you tryied QGraphicsScene::invalidate()?

By the way, I have very similar problem with drawForeground() ..
Please tell me, if you solve this.

[jano_alex_es]

Yep, now it works here. By the way, I don't force it, it's called at each moment, as far as I know as paint() event.

I just needed to move the "update()" statment after QGraphicsScene::drawBackground(painter, rect);