[Qt-interest] paint on QGraphicsView

[caius ligarius]

Hi,

I have a QGraphicsView widget which is used to display an image from a
QImage pointer (pseudo code below).

1) What is the best way to paint pixels on the viewport for the "current
image" which is displayed (example: draw lines, points etc.)
2) What is the quickest way to update an existing QImage data buffer ? (I
tried using setpixel but it's too slow!)

void Class:: DisplayImage(QImage* currImg)
{
     QPixmap np = QPixmap::fromImage(*currImg);

     graphicpixmapitem->setPixmap(np);
     graphicsscene->setSceneRect(0, 0, currImg->width(), currImg->height());
     graphicsscene->addItem(graphicitemSingleView);

     ui.graphicsView->setScene(graphicssceneSingleView);
     ui.graphicsView->show();
}

graphicpixmapitem: is QGraphicsPixmap class member variable
graphicsscene: is QGraphicsScene class member variable
ui.graphicsView: is QGraphicsView class member variable


Thanks,
Caius
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