Here you can find the source of drawArrow(Graphics g1, int x1, int y1, int x2, int y2, int lineWidth)
static void drawArrow(Graphics g1, int x1, int y1, int x2, int y2, int lineWidth)
//package com.java2s; /*/* ww w . j av a 2 s.c o m*/ * Copyright (C) 2013 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.awt.*; import java.awt.geom.AffineTransform; public class Main { static void drawArrow(Graphics g1, int x1, int y1, int x2, int y2, int lineWidth) { // x1 and y1 are coordinates of circle or rectangle // x2 and y2 are coordinates of circle or rectangle, to this point is directed the arrow Graphics2D g = (Graphics2D) g1.create(); double dx = x2 - x1; double dy = y2 - y1; double angle = Math.atan2(dy, dx); int len = (int) Math.sqrt(dx * dx + dy * dy); AffineTransform t = AffineTransform.getTranslateInstance(x1, y1); t.concatenate(AffineTransform.getRotateInstance(angle)); g.transform(t); g.drawLine(0, 0, len, 0); Dimension arrowHeadSize = new Dimension(lineWidth * 6, lineWidth * 3); int basePosition = len - arrowHeadSize.width; int height = arrowHeadSize.height; g.fillPolygon(new int[] { len, basePosition, basePosition, len }, new int[] { 0, -height, height, 0 }, 4); } }