Question

I started with core-plot now and came to some problems. I followed the tutorial from this page: http://www.switchonthecode.com/tutorials/using-core-plot-in-an-iphone-application

and completed with the instructions from this page: http://code.google.com/p/core-plot/wiki/UsingCorePlotInApplications (such as -all_load).

But I still have some problems, I get the following errors:

error: incompatible type for argument 1 of 'setMajorIntervalLength:'
error: request for member 'axisLabelOffset' in something not a structure or union
error: incompatible type for argument 1 of 'setMajorIntervalLength:'
error: request for member 'axisLabelOffset' in something not a structure or union
error: request for member 'bounds' in something not a structure or union
error: request for member 'defaultPlotSymbol' in something not a structure or union
error: request for member 'bounds' in something not a structure or union

Anyone who knows what I am doing wrong?
This is my code:

- (void)viewDidLoad {
    [super viewDidLoad];

    graph = [[CPXYGraph alloc] initWithFrame: self.view.bounds];

    CPLayerHostingView *hostingView = (CPLayerHostingView *)self.view;
    hostingView.hostedLayer = graph;
    graph.paddingLeft = 20.0;
    graph.paddingTop = 20.0;
    graph.paddingRight = 20.0;
    graph.paddingBottom = 20.0;

    CPXYPlotSpace *plotSpace = (CPXYPlotSpace *)graph.defaultPlotSpace;
    plotSpace.xRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-6)
                                                   length:CPDecimalFromFloat(12)];
    plotSpace.yRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-5)
                                                   length:CPDecimalFromFloat(30)];

    CPXYAxisSet *axisSet = (CPXYAxisSet *)graph.axisSet;

    CPLineStyle *lineStyle = [CPLineStyle lineStyle];
    lineStyle.lineColor = [CPColor blackColor];
    lineStyle.lineWidth = 2.0f;

    axisSet.xAxis.majorIntervalLength = [NSDecimalNumber decimalNumberWithString:@"5"];
    axisSet.xAxis.minorTicksPerInterval = 4;
    axisSet.xAxis.majorTickLineStyle = lineStyle;
    axisSet.xAxis.minorTickLineStyle = lineStyle;
    axisSet.xAxis.axisLineStyle = lineStyle;
    axisSet.xAxis.minorTickLength = 5.0f;
    axisSet.xAxis.majorTickLength = 7.0f;
    axisSet.xAxis.axisLabelOffset = 3.0f;

    axisSet.yAxis.majorIntervalLength = [NSDecimalNumber decimalNumberWithString:@"5"];
    axisSet.yAxis.minorTicksPerInterval = 4;
    axisSet.yAxis.majorTickLineStyle = lineStyle;
    axisSet.yAxis.minorTickLineStyle = lineStyle;
    axisSet.yAxis.axisLineStyle = lineStyle;
    axisSet.yAxis.minorTickLength = 5.0f;
    axisSet.yAxis.majorTickLength = 7.0f;
    axisSet.yAxis.axisLabelOffset = 3.0f;

    CPScatterPlot *xSquaredPlot = [[[CPScatterPlot alloc]
                                    initWithFrame:graph.defaultPlotSpace.bounds] autorelease];
    xSquaredPlot.identifier = @"X Squared Plot";
    xSquaredPlot.dataLineStyle.lineWidth = 1.0f;
    xSquaredPlot.dataLineStyle.lineColor = [CPColor redColor];
    xSquaredPlot.dataSource = self;
    [graph addPlot:xSquaredPlot];

    CPPlotSymbol *greenCirclePlotSymbol = [CPPlotSymbol ellipsePlotSymbol];
    greenCirclePlotSymbol.fill = [CPFill fillWithColor:[CPColor greenColor]];
    greenCirclePlotSymbol.size = CGSizeMake(2.0, 2.0);
    xSquaredPlot.defaultPlotSymbol = greenCirclePlotSymbol;  

    CPScatterPlot *xInversePlot = [[[CPScatterPlot alloc]
                                    initWithFrame:graph.defaultPlotSpace.bounds] autorelease];
    xInversePlot.identifier = @"X Inverse Plot";
    xInversePlot.dataLineStyle.lineWidth = 1.0f;
    xInversePlot.dataLineStyle.lineColor = [CPColor blueColor];
    xInversePlot.dataSource = self;
    [graph addPlot:xInversePlot];
}

Answer 1

The example you’re pointing to is out of date and no longer matches the current API for the Core Plot framework. I’d suggest starting with the sample applications that ship with the framework (in the examples directory), as we’ve kept those updated to match any API changes.

For example axisLabelOffset has been renamed to labelOffset, defaultPlotSymbol no longer exists (you set the plotSymbol property on a CPPlot instance), the plot space no longer has a bounds property, and you no longer need to use -initWithFrame: for the CPPlot instances.

Again, just use the sample applications that ship with the framework as a template, and work from there. We haven’t reached a 1.0 release yet, so the API will change as we stabilize and enhance the framework.