gistfile1.rb

class MyController < UIViewController
  def viewDidLoad
    super
    top_view.addSubview chart_view([[0,0], [100,100],
      [10, 20, 20, 15, 35],
      ["#203a65", "#37537c", "#5b7faa", "#aec2d6", "#aec2d6", "#ffffff"]
    )
  end

  def chart_view(frame, data, colors)
    chart_view = CPTGraphHostingView.alloc.initWithFrame frame
    chart_view.backgroundColor = UIColor.clearColor
    chart = PieChart.alloc.initWithData(data, colors: colors, andSize: chart_view.frame.size)
    chart_view.hostedGraph = chart
    chart_view
  end
end


class PieChart < CPTXYGraph
  attr_reader :data, :size, :colors

  def initWithData(data, colors: colors, andSize: size)
    init

    @data = data
    @size = size
    @colors = colors || []

    plot.pieRadius = radius
    plot.identifier = 'this is a chart'
    plot.startAngle = Math::PI/2
    plot.sliceDirection = CPTPieDirectionCounterClockwise

    plot.dataSource = self;
    plot.delegate = self;
    addPlot plot, toPlotSpace: defaultPlotSpace

    self
  end

  def radius
    [ 0.9 * (size.first - 2 * paddingLeft) / 2.0,
      0.9 * (size.last  - 2 * paddingTop ) / 2.0
    ].min
  end

  def numberOfRecordsForPlot(plot)
    data.size
  end

  def numberForPlot(plot, field:fieldEnum, recordIndex:index)
    data[index]
  end

  def sliceFillForPieChart(plot, recordIndex: index)
    color = if colors[index]
      String.new(colors[index]).to_color.asCPTColor
    else
      CPTPieChart.defaultPieSliceColorForIndex(index)
    end
    CPTFill.alloc.initWithColor color
  end

  def plot
    @plot ||= CPTPieChart.alloc.init
  end
end