Core Plot - reversed plot and labels

Question

I have a problem with displaying the correct plot. I used some code from RealTimePlot (http://code.google.com/p/core-plot/source/browse/examples/CorePlotGallery/src/plots/RealTimePlot.m). I do not know why the plot is reversed. There is a photo showing the problem.

- (void)viewDidLoad
{
    [super viewDidLoad];

    [self generateDataSamples];

    CPTGraphHostingView *hostingView = [[[CPTGraphHostingView alloc] initWithFrame:self.view.bounds] autorelease];
    [self.view addSubview:hostingView];

    graph = [[CPTXYGraph alloc] initWithFrame:self.view.bounds];
    hostingView.hostedGraph = graph;


    CPTTheme *theme = [CPTTheme themeNamed:kCPTSlateTheme];
    [graph applyTheme:theme];

    graph.plotAreaFrame.paddingTop = 15;
    graph.plotAreaFrame.paddingRight = 40;
    graph.plotAreaFrame.paddingBottom = 15;
    graph.plotAreaFrame.paddingLeft = 55;

    // Grid line styles
    CPTMutableLineStyle *majorGridLineStyle = [CPTMutableLineStyle lineStyle];
    majorGridLineStyle.lineWidth = 0.75;
    majorGridLineStyle.lineColor = [[CPTColor colorWithGenericGray:0.2] colorWithAlphaComponent:0.75];

    CPTMutableLineStyle *minorGridLineStyle = [CPTMutableLineStyle lineStyle];
    minorGridLineStyle.lineWidth = 0.25;
    minorGridLineStyle.lineColor = [[CPTColor whiteColor] colorWithAlphaComponent:0.1]; 

    // Axes
    // X axis
    CPTXYAxisSet *axisSet = (CPTXYAxisSet *)graph.axisSet;
    CPTXYAxis *x = axisSet.xAxis;
    x.labelingPolicy = CPTAxisLabelingPolicyAutomatic;
    x.orthogonalCoordinateDecimal = CPTDecimalFromUnsignedInteger(0);
    x.majorGridLineStyle = majorGridLineStyle;
    x.minorGridLineStyle = minorGridLineStyle;
    x.minorTicksPerInterval = 9;
    x.title = @"X Axis";
    x.titleOffset = 35.0;
    NSNumberFormatter *labelFormatter = [[NSNumberFormatter alloc] init];
    labelFormatter.numberStyle = NSNumberFormatterNoStyle;
    x.labelFormatter = labelFormatter;
    [labelFormatter release];

    // Y axis
    CPTXYAxis *y = axisSet.yAxis;
    y.labelingPolicy = CPTAxisLabelingPolicyAutomatic;
    y.orthogonalCoordinateDecimal = CPTDecimalFromUnsignedInteger(0);
    y.majorGridLineStyle = majorGridLineStyle;
    y.minorGridLineStyle = minorGridLineStyle;
    y.minorTicksPerInterval = 3;
    y.labelOffset = 5.0;
    y.title = @"Y Axis";
    y.titleOffset = 30.0;
    y.axisConstraints = [CPTConstraints constraintWithLowerOffset:0.0];

    // Rotate the labels by 45 degrees, just to show it can be done.
    //x.labelRotation = M_PI * 0.25;

    // Create the plot
    CPTScatterPlot *dataSourceLinePlot = [[[CPTScatterPlot alloc] init] autorelease];
    dataSourceLinePlot.identifier = kPlotIdentifier;
    dataSourceLinePlot.cachePrecision = CPTPlotCachePrecisionDouble;

    CPTMutableLineStyle *lineStyle = [[dataSourceLinePlot.dataLineStyle mutableCopy] autorelease];
    lineStyle.lineWidth = 3.0;
    lineStyle.lineColor = [CPTColor greenColor];
    dataSourceLinePlot.dataLineStyle = lineStyle;

    dataSourceLinePlot.dataSource = self;
    [graph addPlot:dataSourceLinePlot];

    // Plot space
    CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)graph.defaultPlotSpace;
    plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromUnsignedInteger(0) length:CPTDecimalFromUnsignedInteger(kMaxDataPoints - 1)];
    plotSpace.yRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromUnsignedInteger(0) length:CPTDecimalFromUnsignedInteger(250)];
}

reversed plot

Eric Skroch Eric Skroch · Accepted Answer · 2012-08-08T23:50:11

The iOS CPTGraphHostingView applies a flip transform to the hosted graph so Core Plot can share drawing code between iOS and the Mac. Make sure the hosting view and all of its superviews are using their default transforms.

Core Plot - reversed plot and labels

2 Answers