UIImagePickerController拍照上传图片旋转问题

转载地址：http://www.cnblogs.com/yajunLi/p/5796084.html

问题描述：

手机头像上传，遇到一个怪现象，就是拍照上传时，手机端显示头像正常，但在web端查看会有一个左旋90度的问题。

并且照片竖怕才会有此问题，横拍不存在。

 

原因分析：

手机拍照时，用相机拍摄出来的照片是含有EXIF信息的，在我们得到 UIImage时，可以查看此Image的imageOrientation属性，其实就是指的EXIF中的orientation信息。

如果我们忽略orientation信息，而直接对照片进行像素处理或上传等操作，得到的结果是翻转或者旋转90之后的样子。

这是因为我们执行像素处理或者drawInRect等操作之后，imageOrientaion信息被删除了，imageOrientaion被重设为0，造成照片内容和imageOrientaion不匹配。

所以，在对照片进行处理之前，先将照片旋转到正确的方向，保证返回的imageOrientaion为0。

解决方法：

Swift版：

/**
     照片竖拍  web显示旋转解决:图片大于2M会自动旋转90度

     - parameter aImage: <#aImage description#>

     - returns: <#return value description#>
     */
    class  func  fixOrientation ( aImage : UIImage )- > UIImage   {
        if  aImage . imageOrientation  ==  UIImageOrientation . Up {
            return  aImage
        }

        var  transform  =  CGAffineTransformIdentity

        switch  ( aImage . imageOrientation ) {
        case  . Down ,. DownMirrored :
        transform  =  CGAffineTransformTranslate ( transform ,  aImage . size . width ,  aImage . size . height )
        transform  =  CGAffineTransformRotate ( transform ,  CGFloat ( M_PI ))
        break ;

        case  . Left ,. LeftMirrored :
        transform  =  CGAffineTransformTranslate ( transform ,  aImage . size . width ,  0 )
        transform  =  CGAffineTransformRotate ( transform ,  CGFloat ( M_PI_2 ))
        break ;

        case  . Right ,. RightMirrored :
        transform  =  CGAffineTransformTranslate ( transform ,  0 ,  aImage . size . height )
        transform  =  CGAffineTransformRotate ( transform ,  CGFloat (- M_PI_2 ))
        break ;
        default :
        break ;
        }

        switch  ( aImage . imageOrientation ) {
        case  . UpMirrored ,. DownMirrored :
        transform  =  CGAffineTransformTranslate ( transform ,  aImage . size . width ,  0 )
        transform  =  CGAffineTransformScale ( transform , - 1 ,  1 )
        break ;

        case  . LeftMirrored ,. RightMirrored :
        transform  =  CGAffineTransformTranslate ( transform ,  aImage . size . height ,  0 )
        transform  =  CGAffineTransformScale ( transform , - 1 ,  1 )
        break ;
        default :
        break ;
        }

        let  ctx : CGContextRef  =  CGBitmapContextCreate ( nil ,  Int ( aImage . size . width ),  Int ( aImage . size . height ),
        CGImageGetBitsPerComponent ( aImage . CGImage ),  0 ,
        CGImageGetColorSpace ( aImage . CGImage ),
        1 )!



        CGContextConcatCTM ( ctx ,  transform )
        switch  ( aImage . imageOrientation ) {
        case  . Left ,. LeftMirrored ,. Right ,. RightMirrored :
        CGContextDrawImage ( ctx ,  CGRectMake ( 0 , 0 , aImage . size . height , aImage . size . width ),  aImage . CGImage )
        break ;

        default :
        CGContextDrawImage ( ctx ,  CGRectMake ( 0 , 0 , aImage . size . width , aImage . size . height ),  aImage . CGImage );
        break ;
        }

        let  cgimg : CGImageRef  =  CGBitmapContextCreateImage ( ctx )!
        let  img : UIImage  =  UIImage ( CGImage :  cgimg )
        return  img ;
        }

　　

OC版：

- (UIImage *)fixOrientation:(UIImage *)aImage {

  // No-op if the orientation is already correct
  if  (aImage.imageOrientation == UIImageOrientationUp)
    return  aImage;

  // We need to calculate the proper transformation to make the image upright.
  // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
  CGAffineTransform transform = CGAffineTransformIdentity;

  switch  (aImage.imageOrientation) {
    case  UIImageOrientationDown:
    case  UIImageOrientationDownMirrored:
      transform = CGAffineTransformTranslate(transform, aImage.size.width, aImage.size.height);
      transform = CGAffineTransformRotate(transform, M_PI);
      break ;

    case  UIImageOrientationLeft:
    case  UIImageOrientationLeftMirrored:
      transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);
      transform = CGAffineTransformRotate(transform, M_PI_2);
      break ;

    case  UIImageOrientationRight:
    case  UIImageOrientationRightMirrored:
      transform = CGAffineTransformTranslate(transform, 0, aImage.size.height);
      transform = CGAffineTransformRotate(transform, -M_PI_2);
      break ;
    default :
      break ;
  }

  switch  (aImage.imageOrientation) {
    case  UIImageOrientationUpMirrored:
    case  UIImageOrientationDownMirrored:
      transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);
      transform = CGAffineTransformScale(transform, -1, 1);
      break ;

    case  UIImageOrientationLeftMirrored:
    case  UIImageOrientationRightMirrored:
      transform = CGAffineTransformTranslate(transform, aImage.size.height, 0);
      transform = CGAffineTransformScale(transform, -1, 1);
      break ;
    default :
      break ;
  }

  // Now we draw the underlying CGImage into a new context, applying the transform
  // calculated above.
  CGContextRef ctx = CGBitmapContextCreate( NULL , aImage.size.width, aImage.size.height,
                       CGImageGetBitsPerComponent(aImage.CGImage), 0,
                       CGImageGetColorSpace(aImage.CGImage),
                       CGImageGetBitmapInfo(aImage.CGImage));
  CGContextConcatCTM(ctx, transform);
  switch  (aImage.imageOrientation) {
    case  UIImageOrientationLeft:
    case  UIImageOrientationLeftMirrored:
    case  UIImageOrientationRight:
    case  UIImageOrientationRightMirrored:
      // Grr...
      CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.height,aImage.size.width), aImage.CGImage);
      break ;

    default :
      CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.width,aImage.size.height), aImage.CGImage);
      break ;
  }

  // And now we just create a new UIImage from the drawing context
  CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
  UIImage *img = [UIImage imageWithCGImage:cgimg];
  CGContextRelease(ctx);
  CGImageRelease(cgimg);
  return  img;
}

　　

 

亲测，在完成拍照代理里，获取到图片后，用此方法处理后，再上传服务器，可解决该问题。

//若是图片
var  img : UIImage  =  info [ UIImagePickerControllerOriginalImage ]  as !  UIImage
//保存相册
UIImageWriteToSavedPhotosAlbum ( img ,  self ,  nil ,  nil )

img  =  PublicMethod . fixOrientation ( img )

//压缩图片
let  imgData : NSData  =  UIImageJPEGRepresentation ( img ,  0.2 )!
//上传服务器
self . uploadHeadImg ( imgData ,  headImage :  img )

　　

参考文献：http://blog.csdn.net/hitwhylz/article/details/39518463