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Slowdown issue with DrawAni when drawing multiple Line charts


Posted by jo at 04:57 on Friday 26th January 2024 [link]
When drawing multiple line charts, a speed degradation issue occurs during drawAni. In RGraph.common.core.js, within the RGraph.Background.draw function:

// Reset the line dash
if (typeof args.object.context.setLineDash == 'function') {
args.object.context.setLineDash([1,0]);
}

This part takes a long time. Setting it to the default value like this:

args.object.context.setLineDash([]);

restores the speed to normal.

Please confirm.

Thank you."

Posted by Richard at 11:08 on Friday 26th January 2024 [link]
Thanks very much for identifying the issue. I've added the fix into the code and it will be a part of version 6.17. The updated library is available on GitHub if you want it:

https://raw.githubusercontent.com/heyesr/rgraph/main/libraries/RGraph.common.core.js

I've set up two demo pages that show the difference with the Line chart trace effect:

https://www.rgraph.net/tests/canvas.line/dashed-lines-pre-fix.html
https://www.rgraph.net/tests/canvas.line/dashed-lines-post-fix.html

The difference is quite pronounced!

And with the background grid code being shared between a few libraries (eg bar/line/gantt/hbar/scatter) this is unlikely to just affect the Line chart animations - but those other charts too.

Cheers.

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