java读取jpg图片旋转按比例缩放

 //入口
 public static BufferedImage constructHeatWheelView(int pageWidth, int pageHeight, DoubleHolder scaleHolder) throws ValidateException{

         BufferedImage bi = new BufferedImage(pageWidth, pageHeight, BufferedImage.TYPE_INT_RGB);
         Graphics2D g = (Graphics2D) bi.getGraphics();
         DrawingHelper.clearGraphics(g, pageWidth, pageHeight);
         try {

             //1 读取 jpg 格式图片
             Image srcImage= ImageIO.read(ECSigleton.getInstance().getAppManager().loadImageStream("HeatWheel"));

             //2   旋转 Image
             bi=getImage_rote270(srcImage);
             //3 按比例缩放
             bi=scale(bi,0.75);

         } catch (IOException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
         return bi;
     }

  public static BufferedImage getImage_rote270(Image img)
     {
         int width = img.getWidth(null);
         int height = img.getHeight(null);
         BufferedImage newImg = new BufferedImage(height, width, 1);
         Graphics g = newImg.getGraphics();
         Graphics2D g2d = (Graphics2D) g;
         g2d.rotate(Math.toRadians(-90), 0, 0);
         g2d.drawImage(img, -width, 0, width, height,  null);
         g2d.dispose();
         return newImg;
     }

     public static BufferedImage  scale(BufferedImage src,  double scale) {

             int width = src.getWidth(); // 得到源图宽
             int height = src.getHeight(); // 得到源图长

                 width = (int)(width * scale);
                 height = (int)(height * scale);

             Image image = src.getScaledInstance(width, height,
                     Image.SCALE_DEFAULT);
             BufferedImage tag = new BufferedImage(width, height,
                     BufferedImage.TYPE_INT_RGB);
             Graphics g = tag.getGraphics();
             g.drawImage(image, 0, 0, null); // 绘制缩小后的图
             g.dispose();
             //ImageIO.write(tag, "JPEG", new File(result));// 输出到文件流
         return tag;
     }