上传到网络时，iPhone摄像头图像会旋转

Question

我正在使用UIImagePickerController在iphone上以纵向模式拍照并保存到网络。照片在手机上以纵向显示，但在网页上旋转90度。

如果我下载照片并在Preview（mac）或Photoshop（mac或pc）中查看它，它会再次显示在肖像中。在Windows图片浏览器（电脑）它被旋转到风景。

上传前需要对图像数据应用旋转变换吗？那么我是否还需要删除在Photoshop和Preview中旋转它的元数据？

Answer 1

问题在于图片旋转被添加到照片中，因为EXIF数据没有被大多数浏览器使用。有两种解决方案：

1. 在服务器端应用旋转。我用的是Ruby的插件回形针（由Thoughtbot），只是必须包括在模型中自动定向转换选项的has_attached_file命令：

   has_attached_file：照片，：convert_options => {：所有=>“-auto --orient'}

2. 旋转iPhone应用程序中的照片。这在另一个堆栈溢出问题中解决了;调用scaleAndRotate method用@Squeegy替换图像变换的旋转元数据。

Answer 2

这里是CarrierWavew/MiniMagick的解决方案：http://carrierwave.rubyforge.org/rdoc/classes/CarrierWave/MiniMagick.html

Answer 3

一旦你将图像上传到服务器之前拍照只是通过您所拍摄的图像到一个方法和它肯定适合你

#pragma mark Rotate 
- (UIImage *)scaleAndRotateImage:(UIImage *)image { 
    int kMaxResolution = 640; // Or whatever 

    CGImageRef imgRef = image.CGImage; 

    CGFloat width = CGImageGetWidth(imgRef); 
    CGFloat height = CGImageGetHeight(imgRef); 


    CGAffineTransform transform = CGAffineTransformIdentity; 
    CGRect bounds = CGRectMake(0, 0, width, height); 
    if (width > kMaxResolution || height > kMaxResolution) { 
     CGFloat ratio = width/height; 
     if (ratio > 1) { 
      bounds.size.width = kMaxResolution; 
      bounds.size.height = roundf(bounds.size.width/ratio); 
     } 
     else { 
      bounds.size.height = kMaxResolution; 
      bounds.size.width = roundf(bounds.size.height * ratio); 
     } 
    } 

    CGFloat scaleRatio = bounds.size.width/width; 
    CGSize imageSize = CGSizeMake(CGImageGetWidth(imgRef), CGImageGetHeight(imgRef)); 
    CGFloat boundHeight; 
    UIImageOrientation orient = image.imageOrientation; 
    switch(orient) { 

     case UIImageOrientationUp: //EXIF = 1 
      transform = CGAffineTransformIdentity; 
      break; 

     case UIImageOrientationUpMirrored: //EXIF = 2 
      transform = CGAffineTransformMakeTranslation(imageSize.width, 0.0); 
      transform = CGAffineTransformScale(transform, -1.0, 1.0); 
      break; 

     case UIImageOrientationDown: //EXIF = 3 
      transform = CGAffineTransformMakeTranslation(imageSize.width, imageSize.height); 
      transform = CGAffineTransformRotate(transform, M_PI); 
      break; 

     case UIImageOrientationDownMirrored: //EXIF = 4 
      transform = CGAffineTransformMakeTranslation(0.0, imageSize.height); 
      transform = CGAffineTransformScale(transform, 1.0, -1.0); 
      break; 

     case UIImageOrientationLeftMirrored: //EXIF = 5 
      boundHeight = bounds.size.height; 
      bounds.size.height = bounds.size.width; 
      bounds.size.width = boundHeight; 
      transform = CGAffineTransformMakeTranslation(imageSize.height, imageSize.width); 
      transform = CGAffineTransformScale(transform, -1.0, 1.0); 
      transform = CGAffineTransformRotate(transform, 3.0 * M_PI/2.0); 
      break; 

     case UIImageOrientationLeft: //EXIF = 6 
      boundHeight = bounds.size.height; 
      bounds.size.height = bounds.size.width; 
      bounds.size.width = boundHeight; 
      transform = CGAffineTransformMakeTranslation(0.0, imageSize.width); 
      transform = CGAffineTransformRotate(transform, 3.0 * M_PI/2.0); 
      break; 

     case UIImageOrientationRightMirrored: //EXIF = 7 
      boundHeight = bounds.size.height; 
      bounds.size.height = bounds.size.width; 
      bounds.size.width = boundHeight; 
      transform = CGAffineTransformMakeScale(-1.0, 1.0); 
      transform = CGAffineTransformRotate(transform, M_PI/2.0); 
      break; 

     case UIImageOrientationRight: //EXIF = 8 
      boundHeight = bounds.size.height; 
      bounds.size.height = bounds.size.width; 
      bounds.size.width = boundHeight; 
      transform = CGAffineTransformMakeTranslation(imageSize.height, 0.0); 
      transform = CGAffineTransformRotate(transform, M_PI/2.0); 
      break; 

     default: 
      [NSException raise:NSInternalInconsistencyException format:@"Invalid image orientation"]; 

    } 

    UIGraphicsBeginImageContext(bounds.size); 

    CGContextRef context = UIGraphicsGetCurrentContext(); 

    if (orient == UIImageOrientationRight || orient == UIImageOrientationLeft) { 
     CGContextScaleCTM(context, -scaleRatio, scaleRatio); 
     CGContextTranslateCTM(context, -height, 0); 
    } 
    else { 
     CGContextScaleCTM(context, scaleRatio, -scaleRatio); 
     CGContextTranslateCTM(context, 0, -height); 
    } 

    CGContextConcatCTM(context, transform); 

    CGContextDrawImage(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, width, height), imgRef); 
    UIImage *imageCopy = UIGraphicsGetImageFromCurrentImageContext(); 
    UIGraphicsEndImageContext(); 

    return imageCopy; 
} 

Answer 4

如果在MS Windows中以正确的方向保存图像，以下是手动覆盖EXIF旋转元数据的简单方法。在Windows资源管理器中，右键单击图像文件并选择“顺时针旋转”。执行此操作4次以完全旋转图像，然后图像将对所有系统具有正确的方向。然后你可以将图像上传到你的网络服务器。