code: public static PlotCanvas plot(int[] x, DiscreteDistribution d) {
          double[] lowerBound = {Math.min(x), d.quantile(1 / (x.length + 1.0))};
          double[] upperBound = {Math.max(x), d.quantile(x.length / (x.length + 1.0))};
          PlotCanvas canvas = new PlotCanvas(lowerBound, upperBound);
          canvas.add(new QQPlot(x, d));
          return canvas;
      }
docs: Create a plot canvas with the one sample Q-Q plot to given distribution.
  The x-axis is the quantiles of x and the y-axis is the quantiles of
  given distribution.
  @param x a sample set.
  @param d a distribution.