[RadCartesianChart] Refresh issue when adding data in real time

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Sebastien
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Sebastien asked on 19 May 2022, 06:08 PM
Hi,

1- Run the app
2- After short time, you will see that the chart refreshes.

Data is added in real time on a 1 second timer, you can put the timer at 2 seconds and you will see the issu.e

With very few data, I would expect the Chart to not cause a flickering.

Thank you
Didi
Telerik team
commented on 24 May 2022, 12:05 PM

Hi Sebastien,

Thank you for the provided video and project.

I reproduced the behavior. I will need some time to review the chart implementation and will write back once I have more details on the flickering (by the end of the week).

Didi
Telerik team
commented on 25 May 2022, 01:11 PM

Hi Sebastien, 

The flickering occurs when series are created dynamically. This requires redrawing of many chart elements. The flickering occurs because the elements are recreated and redrawn each time data is added. 

Sebastien
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commented on 25 May 2022, 01:43 PM

Hi,

In all of your Chart documentation (WPF, WinUI, UWP), it is mentioned unmatched performance and real time update. Seeing flickering at 40 points in a chart is not something that I would call performant or it supports real-time update. Sometimes looks fishy I believe. Would it be possible to re-review the case with your team? Thanks

Lance | Manager Technical Support
Telerik team
commented on 27 May 2022, 03:33 PM

Hi Sebastien,

As promised, attached is a modified version of the demo that shows smooth real-time data being displayed by the Chart. Instead of changing your existing code, I added a UserControl which is displayed on MainPage

  1. Run the app and click the Start button
  2. Observe the data is added to the chart every 250 milliseconds without resetting the series
  3. Click stop and wait a second, click start again and observe the delayed data is added to the end of the existing data without flicker

Further Investigation & Workaround

As far why your implementation flickers, I suspect it might be due to the combination of SeriesProvider with multiple series and CombineMode, but I need to leave that final diagnosis up to the team.

In the meantime, can you see if you can define the series into the chart directly instead of using series provider? I've seen some improvement with this alternative.

Sebastien
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commented on 27 May 2022, 06:07 PM | edited

Hi Lance,

Thankfully, our spec supports 5 series at most and your solution works perfectly!! You can see my attached video where I showcase 5 series with faster tick.

The ticket can be closed now.

Thank you
Sébastien
Didi
Telerik team
commented on 30 May 2022, 08:25 AM

I am glad to hear the workaround is suitable for you.

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Didi
Telerik team
answered on 30 May 2022, 08:25 AM

Hi Sebastien,

I have researched the case in detail and here are my findings.

The flickering occurs when SeriesProvider is used. As I explained in my previous reply, the chart redraws many elements and as a result, flickering occurs. I have logged this behavior on your behalf. You can follow the item at this link: https://feedback.telerik.com/uwp/1567041-chart-flickering-occurs-in-real-time-update-when-series-are-added-through-seriesprovider

As my colleague, Lance explained the issue occurs only when using the SeriesProvider.

Regarding the point in our documentation and the sentence, you have marked, yes the chart supports real-time updates.

Regards,
Didi
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