[Qt-qml] Performance issue with Repeater

[Sohail Somani]

Hi,

I have a need to create a bunch of rectangles with different heights in 
a single column.

Essentially it's like a scrollable bar chart but with a large number of 
entries.

The self-contained code I'm using to create this bar chart is attached.

The problem seems to be that when I get to a normal number of elements 
(approx 3000), the initial display performance is incredibly slow. I 
think I understand why: there are a lot of rectangles that need to be 
created.

One option I thought of is to remove all the rectangles that display 
units less than a certain amount but this roughly amounts to having less 
elements and loses precision. Worst case, I can expect about 60,000 
although it is quite literally impossible for any particular user. In my 
testing, 3000 is about normal so I'd like to be able to handle at most 
3-4x that amount if possible.

So any techniques you can recommend for faster display for the attached? 
Delayed loading perhaps?

Thanks in advance!

Sohail
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