[Qt-interest] Qt Charting Component - Feedback Request

[Markus Franke]

Dear Syam,

thanks for your suggestions. Indeed this would be a good approach in order 
to reduce the update rates of the whole display. However, this kind of 
plotting is still not as smooth as a continuously moving waveform.

Best regards,
Markus Franke

qt-interest-bounces+franke.m=sebakmt.com at qt.nokia.com schrieb am 
07.03.2011 15:13:29:

> On 03/07/2011 02:34 PM, Markus Franke wrote: 
> 
> 
> same with us. We're looking for a charting class which is able to 
> efficiently plot data which continously changes over time. Cycle times 
> are also around 50 to 100 milliseconds. Right now we do everything by 
> ourselves based on QWidget. However for a graph like a sinus wave which 
> amplitude continuously changes over time it's always needed to repaint 
> the whole waveform once a new data point is appended to the end. The 
> whole graphic needs to be shifted to the left as we only print the 
values
> of the last few seconds. 
> 
> Is there a way to efficiently plot this kind of data with your charting 
class? 
> Dear Markus,
> 
>   If you don't need a continuously moving waveform (like a scope), then 
> you can avoid shifting all the time. i.e. if you want to display data of 

> last 10 seconds, then you design your plot to display 15 seconds of 
data.
> When the signal reaches the right hand edge, shift the signal to the 
> left, discarding oldest 5 seconds data. This way, you still end up with 
> last 10 seconds data and still have another 5 seconds before you need to 

> shift again. And since shifts happen less frequently, incremental 
> plotting can be employed.
> 
> Syam_______________________________________________
> Qt-interest mailing list
> Qt-interest at qt.nokia.com
> http://lists.qt.nokia.com/mailman/listinfo/qt-interest



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