[Interest] [QGV] Asynchronous painting of millions QGPathItem

[Philip Schuchardt]

Since QGraphicsView can only render in the main gui thread, rendering in a
separate process will prevent the blocking on the main thread. You could
even implement "big pixel" zooming. You zoom in on the visible buffer while
a back buffer is being rendered in the background by the separate process.
This approach doesn't optimize the rendering. It just prevents the main gui
thread from being blocked by the rendering. It would be great if you could
render QGraphicsScene in a non-gui thread, but as far as I can tell you
can't.

On Tue, Dec 6, 2016 at 4:25 AM Ulf Hermann <ulf.hermann at qt.io> wrote:

> Hello,
>
> I had a somewhat similar, but not quite the same problem when building the
> timeline view for the QML profiler in Qt Creator. It's currently usable
> with up to about 1 million events in the timeline and you can zoom and
> scroll it. There might be potential for further optimization. I used the Qt
> Quick SceneGraph API to directly work with OpenGL geometry. The scene graph
> nodes are built on demand and then cached and recycled when applicable. You
> can check out the result in the Qt Creator sources in src/libs/timeline.
>
> br,
> Ulf
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>
-- 
Phi|ip
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