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