Draw arrows in Java Swing

Arrow.java

package com.presidentgame.game.utils;

import com.igormaznitsa.jhexed.engine.HexEngine;
import java.awt.Graphics2D;
import java.awt.Stroke;
import java.awt.geom.GeneralPath;
import java.awt.geom.Point2D;

public enum Arrow {;

  public static void draw (final Graphics2D gfx, final Point2D start, final Point2D end, final Stroke lineStroke, final Stroke arrowStroke, final float arrowSize) {

    final double startx = start.getX();
    final double starty = start.getY();

    gfx.setStroke(arrowStroke);
    final double deltax = startx - end.getX();
    final double result;
    if (deltax == 0.0d) {
      result = Math.PI / 2;
    }
    else {
      result = Math.atan((starty - end.getY()) / deltax) + (startx < end.getX() ? Math.PI : 0);
    }

    final double angle = result;

    final double arrowAngle = Math.PI / 12.0d;

    final double x1 = arrowSize * Math.cos(angle - arrowAngle);
    final double y1 = arrowSize * Math.sin(angle - arrowAngle);
    final double x2 = arrowSize * Math.cos(angle + arrowAngle);
    final double y2 = arrowSize * Math.sin(angle + arrowAngle);

    final double cx = (arrowSize / 2.0f) * Math.cos(angle);
    final double cy = (arrowSize / 2.0f) * Math.sin(angle);

    final GeneralPath polygon = new GeneralPath();
    polygon.moveTo(end.getX(), end.getY());
    polygon.lineTo(end.getX() + x1, end.getY() + y1);
    polygon.lineTo(end.getX() + x2, end.getY() + y2);
    polygon.closePath();
    gfx.fill(polygon);

    gfx.setStroke(lineStroke);
    gfx.drawLine((int) startx, (int) starty, (int) (end.getX() + cx), (int) (end.getY() + cy));
  }

}