[Interest] [QtGraphs] Scalability of CustomSeries for high-density candlestick charting

[Camellia]

Hi all,

I am currently working on a financial project that requires rendering
high-density candlestick charts. My typical dataset ranges from thousands
to tens of thousands of data points (1k - 10k+) per view.

I've successfully implemented the charts using the new *CustomSeries* in Qt
Graphs. However, based on my observations of the scene graph performance,
it appears that CustomSeries might be instantiating a distinct QQuickItem
or Scene Graph node for every single data point. As the dataset grows
towards the 10k+ range, I'm noticing performance bottlenecks during
interactive zooming and panning.

I have two questions for the team or the community:

   1.

   Is CustomSeries primarily designed for smaller datasets where visual
   customization per-item is the priority, or is it intended to scale to these
   higher densities?
   2.

   For use cases involving tens of thousands of structurally identical
   shapes (like candlesticks), does Qt Graphs offer—or plan to offer—a more
   performant "batch-rendered" or "virtualized" series type?

I’m trying to determine if I should continue optimizing my implementation
with CustomSeries or if I should look into lower-level RHI-based rendering
for this scale.

Thank you for the great work on the Qt Graphs module!

Best regards,

Camellia
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