core plot datasource - issue

0
votes

I have a question for optimize a core plot graph, if I want to plot the function y=8*sin(x) I use a parse and I get the value of a range (for example -5,+5), after calculate it I plot the graph. If I drag up or down the plot some value are covered, so they are unnecessary and I can remove it, after this add some point on visible range for have a better line.

Now I have a datasource of more interval, 3 array with the y value of this interval: -5,-2 one of 0,3 and one 4,5 (this number are for example). How can I plot this line on my plot View, I need to add some code like this:

CPTScatterPlot *xSquaredPlot = [[CPTScatterPlot alloc] initWithFrame:graph.defaultPlotSpace.accessibilityFrame];
xSquaredPlot.identifier = @"Grafico";
xSquaredPlot.interpolation = CPTScatterPlotInterpolationLinear;
xSquaredPlot.delegate = self;

CPTMutableLineStyle *lineStyleFunc = [CPTMutableLineStyle lineStyle];
lineStyleFunc.lineWidth = 1.0f;
lineStyleFunc.lineColor = [CPTColor redColor];
xSquaredPlot.dataLineStyle = lineStyleFunc;
xSquaredPlot.dataSource = self;

[graph addPlot:xSquaredPlot];

but the problem i that I don't know how line I have, I need to create it dynamically, how can I do it? adding this code when I create the arrays of new interval? but when I need to update datasource?

1
datasourcecore-plot

1 Answers

1
votes

Core Plot will skip drawing points that fall outside the visible plot area when it can, so you don't have to worry too much about doing that in your datasource. You don't want to be adding and removing a lot of data points as the user scrolls around—that will just cause more work for the plotting code and slow it down.

Since you are plotting a function, one thing you can do is only generate data points in a fairly small range, say just slightly outside the visible x-range. Use a plot space delegate to monitor changes and add points as needed when the user scrolls or zooms the graph.

Use the -insertDataAtIndex:numberOfRecords: method to add data points to the plot. This will have better performance than -reloadData which forces the plot to load all of its data, not just the new values.