import java.awt.geom.*;

static void drawTextAlongLine(Graphics2D g, S text, int x1, int y1, int x2, int y2, int shift) {
  if (y2 == y1 && x2 == x1) ++x2;
  
  new AffineTransform tx;
  double angle = Math.atan2(y2-y1, x2-x1);
  bool flip = abs(angle) > pi()/2;
  if (flip) angle -= pi();
  tx.translate((x1+x2)/2.0, (y1+y2)/2.0);
  tx.rotate(angle);

  AffineTransform old = g.getTransform();
  g.setTransform(tx);
  FontMetrics fm = g.getFontMetrics();
  // int y = shift+fm.getLeading()+fm.getMaxAscent(); // below
  int y = -shift-fm.getMaxDescent(); // above
  g.drawString(text, -fm.stringWidth(text)/2.0f, y);
  g.setTransform(old);
}

Began life as a copy of #1007301