android缩放图片

 public static Bitmap scaleImg(Bitmap bm, int newWidth, int newHeight) {
   // 获得图片的宽高
   int width = bm.getWidth();
   int height = bm.getHeight();
   // 设置想要的大小
   int newWidth1 = newWidth;
   int newHeight1 = newHeight;
   // 计算缩放比例
   float scaleWidth = ((float) newWidth1) / width;
   float scaleHeight = ((float) newHeight1) / height;
   
   // 取得想要缩放的matrix参数
   Matrix matrix = new Matrix();
   matrix.postScale(scaleWidth, scaleHeight);
   // 得到新的图片
   Bitmap newbm = Bitmap.createBitmap(bm, 0, 0, width, height, matrix,
     true);
   if(width != newWidth && height != newHeight){
    freeBitmap(bm);
   }
   return newbm;


  }