real time plotting on iPhone using core plot?

Appbrain picture Appbrain · Mar 8, 2010 · Viewed 20.1k times · Source

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

Brad Larson picture Brad Larson · Mar 8, 2010

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: alt text
(source: sunsetlakesoftware.com)