Question

java 怎么让一个图形绕一个点旋转360度

刚刚学Java，在学translate和rotate，但是不会让一个圆绕一圈

Answer 1

1. import java.awt.Canvas;
2. import java.awt.Graphics;
3. import java.awt.Graphics2D;
4. import java.awt.RenderingHints;
5. import java.awt.image.BufferedImage;
6.  
7. /**
8.  * @author ZhengYesheng
9.  */
10. public class RotateImageCanvas extends Canvas implements Runnable
11. {
12.     private static final long serialVersionUID = -1997487731464495923L;
13.  
14.     BufferedImage img;
15.     BufferedImage rotatedImg;
16.  
17.     int degress = 0;
18.  
19.     public RotateImageCanvas(BufferedImage img)
20.     {
21.         super();
22.         this.img = img;
23.         new Thread(this).start();
24.     }
25.  
26.     @Override
27.     public void run()
28.     {
29.         while (true)
30.         {
31.             //A，与B的代码配合决定旋转的速度
32.             degress += 1;
33.             degress %= 360;
34.             repaint();
35.             try
36.             {
37.                 if (degress == 0)
38.                 {
39.                     //绕一周后等待的时间在这里设置
40.                     Thread.sleep(3 * 1000);
41.                 }
42.                 else
43.                 {
44.                     //考虑到视觉平滑，这里不应大约40。
45.                     Thread.sleep(30);
46.                 }
47.             }
48.             catch (InterruptedException e)
49.             {
50.                 // TODO Auto-generated catch block
51.                 e.printStackTrace();
52.             }
53.         }
54.     }
55.  
56.     @Override
57.     public void paint(Graphics graphics)
58.     {
59.         super.paint(graphics);
60.         //获取旋转指定角度后的图片。为了避免累计误差，这里是用原始图像旋转的
61.         rotatedImg = rotateImage(img, degress);
62.         //绘制旋转后的图片
63.         graphics.drawImage(rotatedImg, 0, 0, this);
64.     }
65.  
66.     /**
67.      * 旋转图片为指定角度。
68.      * 注意：1、这个方法实现了图像的基于中点的旋转，要想绕指定点，需要配合Matrix类
69.      *          2、为避免图像被裁切，结果图片的尺寸也需要动态计算
70.      *          3、现在旋转后有黑色背景，如果不需要这个效果，需要设置结果图片的Alpha模式
71.      * 
72.      * @param bufferedimage
73.      *            目标图像
74.      * @param degree
75.      *            旋转角度
76.      * @return
77.      */
78.     private BufferedImage rotateImage(BufferedImage bufferedimage, int degree)
79.     {
80.         int w = bufferedimage.getWidth();
81.         int h = bufferedimage.getHeight();
82.         int type = bufferedimage.getColorModel().getTransparency();
83.         BufferedImage img;
84.         Graphics2D graphics2d;
85.         (graphics2d = (img = new BufferedImage(w, h, type)).createGraphics())
86.                 .setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
87.         graphics2d.rotate(Math.toRadians(degree), w / 2, h / 2);
88.         graphics2d.drawImage(bufferedimage, 0, 0, null);
89.         graphics2d.dispose();
90.         return img;
91.     }
92. }

Answer 2

import java.awt.Canvas;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.RenderingHints;import java.awt.image.BufferedImage; /** * @author yzw */public class RotateImageCanvas extends Canvas implements Runnable{ private static final long serialVersionUID = -1997487731464495923L; BufferedImage img; BufferedImage rotatedImg; int degress = 0; public RotateImageCanvas(BufferedImage img) { super(); this.img = img; new Thread(this).start(); } @Override public void run() { while (true) { //A，与B的代码配合决定旋转的速度 degress += 1; degress %= 360; repaint(); try { if (degress == 0) { //绕一周后等待的时间在这里设置 Thread.sleep(3 * 1000); } else { //考虑到视觉平滑，这里不应大约40。 Thread.sleep(30); } } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } @Override public void paint(Graphics graphics) { super.paint(graphics); //获取旋转指定角度后的图片。为了避免累计误差，这里是用原始图像旋转的 rotatedImg = rotateImage(img, degress); //绘制旋转后的图片 graphics.drawImage(rotatedImg, 0, 0, this); } /** * 旋转图片为指定角度。 * 注意：1、这个方法实现了图像的基于中点的旋转，要想绕指定点，需要配合Matrix类 * 2、为避免图像被裁切，结果图片的尺寸也需要动态计算 * 3、现在旋转后有黑色背景，如果不需要这个效果，需要设置结果图片的Alpha模式 * * @param bufferedimage * 目标图像 * @param degree * 旋转角度 * @return */ private BufferedImage rotateImage(BufferedImage bufferedimage, int degree) { int w = bufferedimage.getWidth(); int h = bufferedimage.getHeight(); int type = bufferedimage.getColorModel().getTransparency(); BufferedImage img; Graphics2D graphics2d; (graphics2d = (img = new BufferedImage(w, h, type)).createGraphics()) .setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR); graphics2d.rotate(Math.toRadians(degree), w / 2, h / 2); graphics2d.drawImage(bufferedimage, 0, 0, null); graphics2d.dispose(); return img; }}