Working with Core Plot trunk as at 22/08/2011

gistfile1.m

// Modified from: http://www.switchonthecode.com/tutorials/using-core-plot-in-an-iphone-application
// NOTE: needs -load_all linker flag; might not be quite right - red/blue data line styles are not working

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    graph = [[CPTXYGraph alloc] initWithFrame: self.view.bounds];
    
    CPTGraphHostingView *hostingView = (CPTGraphHostingView *)self.view;
    hostingView.hostedGraph = graph;
    graph.paddingLeft = 20.0;
    graph.paddingTop = 20.0;
    graph.paddingRight = 20.0;
    graph.paddingBottom = 20.0;
    
    CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)graph.defaultPlotSpace;
    plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(-6)
                                                   length:CPTDecimalFromFloat(12)];
    plotSpace.yRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(-5) 
                                                   length:CPTDecimalFromFloat(30)];
 
    CPTMutableLineStyle *lineStyle = [CPTMutableLineStyle lineStyle];
    lineStyle.lineColor = [CPTColor blackColor];
    lineStyle.lineWidth = 2.0f;
    
    CPTAxis *xAxis = [graph.axisSet.axes objectAtIndex: 0];
    CPTAxis *yAxis = [graph.axisSet.axes objectAtIndex: 1];
    xAxis.majorIntervalLength = [[NSDecimalNumber decimalNumberWithString:@"5"] decimalValue];
    xAxis.minorTicksPerInterval = 4;
    xAxis.majorTickLineStyle = lineStyle;
    xAxis.minorTickLineStyle = lineStyle;
    xAxis.axisLineStyle = lineStyle;
    xAxis.minorTickLength = 5.0f;
    xAxis.majorTickLength = 7.0f;
    xAxis.labelOffset = 3.0f;
    
    yAxis.majorIntervalLength = [[NSDecimalNumber decimalNumberWithString:@"5"] decimalValue];
    yAxis.minorTicksPerInterval = 4;
    yAxis.majorTickLineStyle = lineStyle;
    yAxis.minorTickLineStyle = lineStyle;
    yAxis.axisLineStyle = lineStyle;
    yAxis.minorTickLength = 5.0f;
    yAxis.majorTickLength = 7.0f;
    yAxis.labelOffset = 3.0f;
    
    CPTScatterPlot *xSquaredPlot = [[CPTScatterPlot alloc] init];
    xSquaredPlot.identifier = @"X Squared Plot";

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

    xSquaredPlot.dataSource = self;
    [graph addPlot:xSquaredPlot];
    
    CPTPlotSymbol *greenCirclePlotSymbol = [CPTPlotSymbol ellipsePlotSymbol];
    greenCirclePlotSymbol.fill = [CPTFill fillWithColor:[CPTColor greenColor]];
    greenCirclePlotSymbol.size = CGSizeMake(2.0, 2.0);
    xSquaredPlot.plotSymbol = greenCirclePlotSymbol;  
    
    CPTScatterPlot *xInversePlot = [[CPTScatterPlot alloc] init];
    xInversePlot.identifier = @"X Inverse Plot";

    CPTMutableLineStyle *blueLineStyle = [CPTMutableLineStyle lineStyle];
    lineStyle.lineColor = [CPTColor blueColor];
    lineStyle.lineWidth = 1.0f;    
    xInversePlot.dataLineStyle = blueLineStyle;
    
    xInversePlot.dataSource = self;
    [graph addPlot:xInversePlot];
    
}


#pragma mark - CPTPlotDataSource

-(NSUInteger)numberOfRecordsForPlot:(CPTPlot *)plot {
    return 51;
}

-(NSNumber *)numberForPlot:(CPTPlot *)plot 
                     field:(NSUInteger)fieldEnum 
               recordIndex:(NSUInteger)index 
{
    double val = (index/5.0)-5;
    
    if(fieldEnum == CPTScatterPlotFieldX)
    { return [NSNumber numberWithDouble:val]; }
    else
    { 
        if(plot.identifier == @"X Squared Plot")
        { return [NSNumber numberWithDouble:val*val]; }
        else
        { return [NSNumber numberWithDouble:1/val]; }
    }
}