please include function drawThoughtLine.

static int drawThoughtArrow_size = 15;

static void drawThoughtArrow(BufferedImage bg,
  BufferedImage img1, int x1, int y1,
  BufferedImage img2, int x2, int y2) {
  double cs = thoughtCircleSize(img2)/2;
  double dist = pointDistance(x1, y1, x2, y2);
  double arrowLen = drawThoughtArrow_size*drawArrowHead_length-1;
  Pt v = blendPoints(new Pt(x2, y2), new Pt(x1, y1), (cs-1+arrowLen)/dist);
  Pt p = blendPoints(new Pt(x2, y2), new Pt(x1, y1), (cs-1)/dist);
  Graphics2D g = imageGraphics(bg);
  g.setColor(Color.white);
  g.setStroke(new BasicStroke(drawThoughtLine_width));
  g.drawLine(x1, y1, v.x, v.y);
  //g.setColor(Color.red); // XXX
  //g.fillOval(p.x-10, p.y-10, 20, 20); // XXX
  g.setColor(Color.white);
  drawArrowHead(g, x1, y1, p.x, p.y, drawThoughtArrow_size);
  g.dispose();
}