Draw many markers on a picture using Qt
<p>What is the efficient way of drawing many markers on a picture (a local map) using Qt?</p>

<p>I am using QGraphicsview/scene and I need markers to be selectable and draggable.</p>

<p>My problem can be exactly reporduced by using Qt's 40000 chips example. In the example, you can zoom in and out.</p>

<p>When you zoom out to the lowest level (where your can see all the chips), everything just became painfully lag (including selection and dragging).</p>

<p>My code is modified from the chips example, so it has the same behavior.
I need to drag many items (1000+) together smoothly.</p>

<p>Any suggestions on how to improve this? </p>

<p>Do I have to painfully implement my own drawing engine using OpenGL?</p>