SfChart: Drag to see older data

Question

Hello, I'm trying to display a set of X;Y data with line series in SfChart. The data is continuously updated with new values along X axis.

The plot must always show the latest 30 points, but I want the user to be able to go back to the older values in the X axis by means of dragging/swiping, while new data keeps being added to the end.

So the workflow will be:

1) The plot inits with 0 data and starts to be filled with the first 30 items. In this fragment of time, the line series must start appearing from the rightmost edge of the plot, reaching the leftmost.

2) When new points gets added after the first 30, the older ones must disappear. The view keeps showing the latest 30 points.

3) The user can drag back the plot to see older data. When the dragging ends, the viewport must be sticky to that particular point in time, while the new data (not visible) keeps getting added.

4) Press "RESET" button to go back to the rightmost edge and unlock the "animation".

I attach a sample app (tested on Android) where I cannot achieve the underlined points:
Point 1) before reaching the first 30 points, the plot if filled completely and the lines gets stretched.

Point 3) I can drag to see older data, but the plot keeps moving. I've played with "AutoScrollingDelta" property for this but it's not working as intended.

Can you help me to solve these 2 issues?

Attachment: PlotDragTest_56ccd634.zip

Yuvaraj Palanisamy · Answer

Hi Alessandro, 
 
Greetings from Syncfusion. 
 
We have analyzed your query & sample, and we tried to provide the requirement through workaround with checking the possibility but due to having the limitation at the framework level, we can’t proceed this further. To resolve the framework limitation, we need to handle it at our source end.  
 
This is similar to the “Lazy data point support in Xamarin.Forms SfChart”. Already we have logged this as a feature. We will prioritize the features every release based on the demands and we do not have an immediate plan to implement this since we committed with already planned work. So, this feature will be available for any of our upcoming releases.    
   
You can track the status of this feature from below link    
Link:  https://www.syncfusion.com/feedback/18969/support-for-lazy-loading-data-update-in-live-chart   
    
Please cast your vote to make it count and If you have any more specifications/suggestions to the feature request, you can add it as a comment in the portal.   
 
Regards,   Yuvaraj.

Alessandro · Answer

Thanks for your feedback. I suppose the "Lazy data point" feature is relative to "point 3" in my list.Anyway, I cannot see the feature using the provided link. It takes me to my Dashboard with no items to show.Maybe it has "private" visibility?

Yuvaraj Palanisamy · Answer

Hi Alessandro, 
 
Sorry for the inconvenience. 
 
Now you can access the feedback link and please track the status of this feature from below link    
Link:  https://www.syncfusion.com/feedback/18969/support-for-lazy-loading-data-update-in-live-chart   
 
Regards, 
Yuvaraj.

Alessandro · Answer

Sorry again. It seems that I am able to open the linked feedback only if I am not logged.Instead if I log-in (in order to upcast my vote), then the link redirects me to my dashboard, so I can't see the Feature anymore.

Yuvaraj Palanisamy · Answer

Hi Alessandro, 
 
Sorry for the delay. 
 
We suspect that the time of your login, service may down for few seconds. if login is down the reported issue might cause. 
 
To resolve this problem, could you please open this url https://www.syncfusion.com/feedback  and clear browser cookie for Syncfusion site, logout and try to login again. 
 
  
 
  
 
Please let us know know if you have any concern. 
 
Regards, 
Yuvaraj.

Alessandro · Answer

Still not working. Tried clearing all the browser cache+cookies.When logged, the link points me to https://www.syncfusion.com/support/directtrac/incidents

Yuvaraj Palanisamy · Answer

Hi Alessandro, 

We regret for the inconvenience. 

We have found a problem in Email verification of your account and fixed. So please once again clear cookie, logout and login again to access Feedback. Hope now you will able to view feedback without any issue. 
 
Regards, 
Yuvaraj.