绘制单向箭头、双向箭头
package com.xiangqian.swing; import javax.swing.*; import java.awt.*; import java.awt.geom.GeneralPath; import java.awt.geom.Line2D; import java.awt.geom.Point2D; /** * 绘制箭头 * * @author xiangqian * @date 16:00 2019/10/31 */ public class DrawArrow { /** * 绘制面板 * * @author xiangqian * @date 15:38 2019/11/03 */ public static class DrawPanel extends JPanel { private BasicStroke lineStroke; public DrawPanel() { lineStroke = new BasicStroke(2.0f); } @Override protected void paintComponent(Graphics g) { draw((Graphics2D) g); } /** * 绘制 * * @param g2d */ private void draw(Graphics2D g2d) { Line2D.Double line2D = null; Arrow.Attributes arrowAttributes = null; // 绘制线的“方向1”箭头 line2D = new Line2D.Double(120, 100, 300, 300); arrowAttributes = new Arrow.Attributes(); drawLineArrowDirection1(g2d, arrowAttributes, line2D); // 绘制线的“方向2”箭头 line2D = new Line2D.Double(110, 330, 300, 330); arrowAttributes = new Arrow.Attributes(); arrowAttributes.angle = 45; arrowAttributes.height = 80; drawLineArrowDirection2(g2d, arrowAttributes, line2D); // 绘制线的“双向”箭头 line2D = new Line2D.Double(500, 200, 260, 200); arrowAttributes = new Arrow.Attributes(); arrowAttributes.angle = 30; arrowAttributes.height = 40; drawLineArrowDirectionAll(g2d, arrowAttributes, line2D); } /** * 绘制线的“方向1”箭头 * * @param g2d * @param arrowAttributes 箭头属性 * @param line2D 线 */ private void drawLineArrowDirection1(Graphics2D g2d, Arrow.Attributes arrowAttributes, Line2D.Double line2D) { drawLine(g2d, line2D); drawArrow(g2d, arrowAttributes, line2D.getP1(), line2D.getP2()); } /** * 绘制线的“方向2”箭头 * * @param g2d * @param arrowAttributes 箭头属性 * @param line2D 线 */ private void drawLineArrowDirection2(Graphics2D g2d, Arrow.Attributes arrowAttributes, Line2D.Double line2D) { drawLine(g2d, line2D); drawArrow(g2d, arrowAttributes, line2D.getP2(), line2D.getP1()); } /** * 绘制线的“双向”箭头 * * @param g2d * @param arrowAttributes 箭头属性 * @param line2D 线 */ private void drawLineArrowDirectionAll(Graphics2D g2d, Arrow.Attributes arrowAttributes, Line2D.Double line2D) { drawLine(g2d, line2D); drawArrow(g2d, arrowAttributes, line2D.getP1(), line2D.getP2()); drawArrow(g2d, arrowAttributes, line2D.getP2(), line2D.getP1()); } /** * 绘制线 * * @param g2d * @param line2D */ private void drawLine(Graphics2D g2d, Line2D.Double line2D) { g2d.setColor(Color.BLACK); g2d.setStroke(lineStroke); g2d.draw(line2D); } /** * 绘制箭头 * * @param g2d * @param arrowAttributes 箭头属性 * @param point1 线的第一个点 * @param point2 线的第二个点 */ private void drawArrow(Graphics2D g2d, Arrow.Attributes arrowAttributes, Point2D point1, Point2D point2) { // 获取Arrow实例 Arrow arrow = getArrow(arrowAttributes, point1, point2); // 构建GeneralPath GeneralPath arrow2D = new GeneralPath(); arrow2D.moveTo(arrow.point1.x, arrow.point1.y); arrow2D.lineTo(arrow.point2.x, arrow.point2.y); arrow2D.lineTo(arrow.point3.x, arrow.point3.y); arrow2D.closePath(); // 绘制 g2d.setColor(arrow.attributes.color); g2d.fill(arrow2D); } /** * 获取箭头实体类 * * @param arrowAttributes 箭头属性 * @param point1 线的第一个点 * @param point2 线的第二个点 * @return */ private Arrow getArrow(Arrow.Attributes arrowAttributes, Point2D point1, Point2D point2) { Arrow arrow = new Arrow(arrowAttributes); // 计算斜边 double hypotenuse = arrow.attributes.height / Math.cos(Math.toRadians(arrow.attributes.angle / 2)); // 计算当前线所在的象限 int quadrant = -1; if (point1.getX() > point2.getX() && point1.getY() < point2.getY()) { quadrant = 1; } else if (point1.getX() < point2.getX() && point1.getY() < point2.getY()) { quadrant = 2; } else if (point1.getX() < point2.getX() && point1.getY() > point2.getY()) { quadrant = 3; } else if (point1.getX() > point2.getX() && point1.getY() > point2.getY()) { quadrant = 4; } // 计算线的夹角 double linAngle = getLineAngle(point1.getX(), point1.getY(), point2.getX(), point2.getY()); if (Double.isNaN(linAngle)) { // 线与x轴垂直 if (point1.getX() == point2.getX()) { if (point1.getY() < point2.getY()) { linAngle = 90; } else { linAngle = 270; } quadrant = 2; } } // 线与y轴垂直 else if (linAngle == 0) { if (point1.getY() == point2.getY()) { if (point1.getX() < point2.getX()) { linAngle = 0; } else { linAngle = 180; } quadrant = 2; } } // 上侧一半箭头 double xAngle = linAngle - arrow.attributes.angle / 2; // 与x轴夹角 double py0 = hypotenuse * Math.sin(Math.toRadians(xAngle)); // 计算y方向增量 double px0 = hypotenuse * Math.cos(Math.toRadians(xAngle)); // 计算x方向增量 // 下侧一半箭头 double yAngle = 90 - linAngle - arrow.attributes.angle / 2; // 与y轴夹角 double px1 = hypotenuse * Math.sin(Math.toRadians(yAngle)); double py1 = hypotenuse * Math.cos(Math.toRadians(yAngle)); // 第一象限 if (quadrant == 1) { px0 = -px0; px1 = -px1; } else if (quadrant == 2) { // do nothing } else if (quadrant == 3) { py0 = -py0; py1 = -py1; } else if (quadrant == 4) { py0 = -py0; px0 = -px0; px1 = -px1; py1 = -py1; } // build arrow.point1 = new Point2D.Double(); arrow.point1.x = point1.getX(); arrow.point1.y = point1.getY(); arrow.point2 = new Point2D.Double(); arrow.point2.x = point1.getX() + px0; arrow.point2.y = point1.getY() + py0; arrow.point3 = new Point2D.Double(); arrow.point3.x = point1.getX() + px1; arrow.point3.y = point1.getY() + py1; return arrow; } /** * 获取线与X轴的夹角 * * @param x1 * @param y1 * @param x2 * @param y2 * @return */ protected double getLineAngle(double x1, double y1, double x2, double y2) { double k1 = (y2 - y1) / (x2 - x1); double k2 = 0; return Math.abs(Math.toDegrees(Math.atan((k2 - k1) / (1 + k1 * k2)))); } } /** * 箭头实体类 * * @author xiangqian * @date 16:06 2019/10/31 */ public static class Arrow { Attributes attributes; Point2D.Double point1; Point2D.Double point2; Point2D.Double point3; public Arrow(Attributes attributes) { this.attributes = attributes; } /** * 箭头属性 * * @author xiangqian * @date 15:41 2019/11/03 */ public static class Attributes { double height; // 箭头的高度 double angle; // 箭头角度 Color color; // 箭头颜色 public Attributes() { this.height = 60; this.angle = 30; this.color = Color.BLACK; } } } public static void main(String[] args) { JFrame frame = new JFrame(); frame.setTitle("绘制箭头"); Dimension dimension = new Dimension(800, 600); frame.setSize(dimension); frame.setLocationRelativeTo(null); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setContentPane(new DrawPanel()); frame.setVisible(true); } }
