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Tag Archives: Qt 4.4

Grabbing all QGraphicItems current viewable in a QGraphicView

The best way to get a list of all items current displayed inside the QGraphicsView is done through the combination of three steps:

get viewing rectangle
get items intersecting or inside rectangle
check for visibility

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QList<QGraphicsItem* > viewItems = m_pView->items(m_pView->rect());
 
for(int i=0; i < viewItems.size(); ++i) {
if(viewItems.at(i)->isVisible()) {
//payload
}
}

Do not use other rectangle functions like sceneRect(), childrenRect(), contentsRect(), etc… as they [...]

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Making a QPixmap transparent the Right Way

The Problem
The classic situation that this problem can occur is when one wants to create a QPixmap with a transparent background and then draws on only some of the available pixels. This process is akin to creating a transparent GIF. Well there is a wrong way and a right way. I discovered this because I [...]

Posted in Qt Code | Also tagged , , | Leave a comment