[Interest] efficient drawing advice

[william.crocker at analog.com]

On 03/26/2014 06:35 AM, Graham Labdon wrote:
> Hi
> My application needs to display a series of 'traces'.
> Each trace will consist of 5000+ points and there can be up to 50 traces.
> I would be grateful of some pointers on how to do this in the most efficient way -
> QPainter on a widget
> Use of OpenGL
> QGraphicsScene
> Which of these will be the most efficient at displaying the data quickly?
>

Create trace abstracts (with reduced point counts) for the purposes of drawing.
In the extreme case, if a trace is close enough to a straight line (given
the resolution of the display) the trace could be abstracted as 2 points.
Your cache of abstractions probably needs to depend on your zoom level.
This works for me and I have traces with millions of points.
I also capitalize on the fact that my traces are (thankfully) monotonic
in the X coordinate.

> Thanks for your time
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