[Interest] Double-buffering QGraphicsItem with QImage on retina display

[Ch'Gans]

On 17 March 2017 at 16:01, Patrick Stinson <patrickkidd at gmail.com> wrote:
> Hi there!
>
> I am implementing handwriting with the apple pencil and am double-buffering each stroke on a QImage before passing the resulting pixmap and bounding rect for the stroke to a QGraphicsItem. The problem is that painting to the QImage is not at retina resolution which is what you get when you paint directly to the scene via QGraphicsItem::paint.
>
> Does anyone have a suggestion for how to handle this?
>
> Should I just double the QImage size and then translate the coordinates appropriately? Then half the target rect in QPainter::drawPixmap(const Rect &target, const QPixmap &, const QSize &source)? Or is there a more elegant way to do it?
>

Have you tried QGraphicsItem::DeviceCoordinateCache ?

My 2 cents

> Thanks!
> -P
>
>
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