Change line style of CPScatterPlot for different points

问题

I'm using coreplot on ios and have a scatterplot. Is it possible to vary the line style depending on the point being plotted? I've only found how to set it for the whole plot.

回答1:

Yes. Make sure your graph delegate conforms to CPScatterPlotDelegate by implementing -symbolForScatterPlot:recordIndex:. Here's a working implementation which returns a different symbol for the index which matches _selectedIndex:

- (CPPlotSymbol *)symbolForScatterPlot:(CPScatterPlot *)plot recordIndex:(NSUInteger)index
{   
    CPMutableLineStyle *symbolLineStyle = [CPMutableLineStyle lineStyle];
    symbolLineStyle.lineColor = [CPColor blackColor];
    CPPlotSymbol *plotSymbol = [CPPlotSymbol ellipsePlotSymbol];
    plotSymbol.lineStyle = symbolLineStyle;

    if (_selectedIndex != NSNotFound && index == _selectedIndex) 
    {
        plotSymbol.symbolType = CPPlotSymbolTypeDiamond;
        plotSymbol.size = CGSizeMake(12, 12);
        plotSymbol.fill = [CPFill fillWithColor:[CPColor redColor]];
    }
    else
    {
        plotSymbol.symbolType = CPPlotSymbolTypeEllipse 
        plotSymbol.size = CGSizeMake(8, 8);
        plotSymbol.fill = [CPFill fillWithColor:[CPColor greenColor]];  
    }
    return plotSymbol;
}

来源：https://stackoverflow.com/questions/6479350/change-line-style-of-cpscatterplot-for-different-points