real time plotting on iPhone using core plot?

Question

I want to use core-plot for drawing line graph dynamically. data won't come at a time, we will be receiving point by point dynamically.

Is it possible to draw the chart dynamically using core-plot i.e drawing point by point as on when we receive the (x,y) point?

Please help me, Thanks.

Answer 1

Yes, you can do this reasonably easily. For each received data point, append it to an array of values to display. As these data points come in, call -reloadData on the Core Plot graph (or just the particular plot) to redraw the graph, passing in the array you just added a value to in response to the -numbersForPlot:field:recordIndexRange: delegate method.

If you need to adjust the plot range to track your data points (for a moving ticker), recalculate the new CPPlotRange for the X axis and set the plot space's xRange property to that.

Use the CPTestApp-iPhone, AAPLot, or StockPlot examples as templates for how to set up the line chart overall, and modify from that starting point.

I do something similar to this on the Mac in a scientific application:

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Answer 2

Sounds like you could make use of a demo project I put together and wrote about here (not core plot related though).

It draws a EKG graph but should easily be modified to use another input than the repeated "heart beat"...See line 320 in EAGLView.m where the indata is entered into the array.