When I do the following, is there a full copy operation happening under the hood or does this share memory?

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QWebElement el = page()->mainFrame()->findFirstElement("#canvas0");

QImage image(el.geometry().width(), el.geometry().height(), QImage::Format_ARGB32);
QPainter painter(&image);
el.render(&painter);
painter.end();

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I'm doing that so that I can then use QImage to get the pixel value at the mouse position:

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QRgb rgbVal = image.pixel(mouseEvent->x(), mouseEvent->y());
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If I do that on each mousemove event, and it's copying and not sharing memory, I worry about performance.. Perhaps there is a better way for me to get the pixel value at the mouse-location from the QWebView widget itself?