private static void renderROC(
      Graphics2D g2d, ClassifierOutput classifierOutput, WriteTextFile out) {
    Collections.sort(classifierOutput.scoreLabelPairs);
    int postiveCount = countPositives(classifierOutput);
    g2d.setColor(new Color(200, 0, 0));
    g2d.setStroke(new BasicStroke(4));
    float areaWidth = width - 2 * borderWidth;
    float areaHeight = height - 2 * borderWidth;
    float x = borderWidth;
    float y = height - borderWidth;
    float previousX = x;
    float previousY = y;
    double score = classifierOutput.scoreLabelPairs.get(0).score;
    int fpCount = 0;
    int tpCount = 0;
    for (ScoreLabelPair pair : classifierOutput.scoreLabelPairs) {
      if (pair.score != score) { // In case of a tie, just make a linear interpolation
        g2d.draw(new Line2D.Float(previousX, previousY, x, y));
        previousX = x;
        previousY = y;
        score = pair.score;
      }

      if (pair.label) tpCount++;
      else fpCount++;
      float fpr =
          (float) fpCount / (float) (classifierOutput.scoreLabelPairs.size() - postiveCount);
      float tpr = (float) tpCount / (float) postiveCount;
      if (out != null) out.writeln(Float.toString(fpr) + "," + Float.toString(tpr));
      x = borderWidth + fpr * areaWidth;
      y = height - borderWidth - tpr * areaHeight;
    }
    g2d.draw(new Line2D.Float(previousX, previousY, x, y));
    if (out != null) out.writeln("1,1");
  }
  public static void createROC(ClassifierOutput classifierOutput, String filename) {
    WriteTextFile out = null;
    if (outputROCcsv) {
      out = new WriteTextFile(filename.replace(".gif", ".csv"));
      out.writeln("FPR,TPR");
    }
    BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
    Graphics2D g2d = (Graphics2D) img.getGraphics();
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    g2d.setColor(Color.WHITE);
    g2d.fillRect(0, 0, width, height);

    renderAxes(g2d, 0.2f, 1f);
    // renderDiagonal(g2d);
    renderROC(g2d, classifierOutput, out);

    if (includeAuCinROC) {
      double auc =
          ClassifierEvaluator.areaUnderCurveConfidenceInterval(classifierOutput).pointEstimate;
      g2d.setColor(Color.black);
      g2d.setFont(new Font("Arial", Font.PLAIN, 50));
      FontMetrics metrics = g2d.getFontMetrics();
      String text = "AUC = " + StringUtilities.formatNumber("0.00", auc);
      int textWidth = metrics.stringWidth(text);
      int textHeight = metrics.getHeight();
      g2d.drawString(
          text, Math.round(width - textWidth - borderWidth), Math.round(height - textHeight) + 7);
    }
    try {
      ImageIO.write(img, "GIF", new File(filename));
    } catch (IOException e) {
      e.printStackTrace();
    }
    if (out != null) out.close();
  }