Using Charts library for real-time plotting

[rforouzanfar]

Hi Daniel,

Thanks a lot for this great API.

I'm using Charts to plot ECG data points (versus time) in real-time and I have 100 data points coming from hardware per second. I'm saving the data in database and then plot them. Here is what I'm using to clear the chartview as well ECG voltages and times each time I'm reseting the graph:

[self.chartView clear];
[self.chartView notifyDataSetChanged];
[self.ecgVoltage removeAllObjects];
[self.ecgDate removeAllObjects];

Although I have changed the database from Core Data to Realm, I am still experiencing slow processing. Is there anything else I could do on the plotting end to save some extra processing? I'm drawing every 50 x-index, though I was wondering if there would be any way that I could assign x-index to some of my y-values as it seems to have a high CPU usage?

P.S. I thought of using custom min and max y values, as they should be refreshed due to possible noises

[liuxuan30]

Have you checked what functions takes lots of time or the CG is slow? I guess you need to use timer to measure it first. Then you will have a clear mind which part can be improved.

[danielgindi]

You do not need to read the whole dataset for each frame rendering, and do not need to clear.

Just add the new entries (and drop old, unnecessary entries).
Then you could call notifyDataSetChanged

Btw - native Realm support coming soon cross-platform, courtesy of Realm. :-)

[liuxuan30]

god, I just know Realm today and seems awesome. Seems time to rewrite my model? LOL

[AwaisFayyaz]

Hi Daniel,

Thanks for the great library. Can you tell me if this kind of real time plotting is possible using your charts library?

[thierryH91200]

do you want something like that?

realtime.mov.zip

[AwaisFayyaz]

@thierryH91200 My values can go positive as well as negative, as depicted in the attached gif. and i need bars, not line.

[thierryH91200]

do you want the source ??

this is just an example

[kartiksharma007]

hi just wanted to ask if we in any way you can help as the data which we have is in a single array , so that means no x or y axis.

[kartiksharma007]

data.json.zip