Comment 8 for bug 1220575

Just had a look at the score formula again and I think this is the correct version:

int span = w - margin * 2;
for (int i = 0; i < span; i++) {
  float score = (float) i / span;
  g.setColor(getScoreColor(score));
  g.drawLine(margin + i, y1, margin + i, y2);
}