java读取jpg图片旋转按比例缩放

 1 //入口
 2 public static BufferedImage constructHeatWheelView(int pageWidth, int pageHeight, DoubleHolder scaleHolder) throws ValidateException{
 3      
 4         BufferedImage bi = new BufferedImage(pageWidth, pageHeight, BufferedImage.TYPE_INT_RGB);
 5         Graphics2D g = (Graphics2D) bi.getGraphics();
 6         DrawingHelper.clearGraphics(g, pageWidth, pageHeight);
 7         try {
 8         
 9             //1 读取 jpg 格式图片
10             Image srcImage= ImageIO.read(ECSigleton.getInstance().getAppManager().loadImageStream("HeatWheel"));
11             
12             //2   旋转 Image
13             bi=getImage_rote270(srcImage);
14             //3 按比例缩放
15             bi=scale(bi,0.75);
16              
17         } catch (IOException e) {
18             // TODO Auto-generated catch block
19             e.printStackTrace();
20         }                
21         return bi;    
22     }
23     
24  public static BufferedImage getImage_rote270(Image img)
25     {
26         int width = img.getWidth(null);
27         int height = img.getHeight(null);
28         BufferedImage newImg = new BufferedImage(height, width, 1);
29         Graphics g = newImg.getGraphics();
30         Graphics2D g2d = (Graphics2D) g;
31         g2d.rotate(Math.toRadians(-90), 0, 0);
32         g2d.drawImage(img, -width, 0, width, height,  null);
33         g2d.dispose();
34         return newImg;
35     }
36     
37     public static BufferedImage  scale(BufferedImage src,  double scale) {
38              
39             int width = src.getWidth(); // 得到源图宽
40             int height = src.getHeight(); // 得到源图长
41          
42                 width = (int)(width * scale);
43                 height = (int)(height * scale);
44              
45             Image image = src.getScaledInstance(width, height,
46                     Image.SCALE_DEFAULT);
47             BufferedImage tag = new BufferedImage(width, height,
48                     BufferedImage.TYPE_INT_RGB);
49             Graphics g = tag.getGraphics();
50             g.drawImage(image, 0, 0, null); // 绘制缩小后的图
51             g.dispose();
52             //ImageIO.write(tag, "JPEG", new File(result));// 输出到文件流
53         return tag;
54     }
55