上傳到網絡時，iPhone攝像頭圖像會旋轉

Question

我正在使用UIImagePickerController在iphone上以縱向模式拍照並保存到網絡。照片在手機上以縱向顯示，但在網頁上旋轉90度。

如果我下載照片並在Preview（mac）或Photoshop（mac或pc）中查看它，它會再次顯示在肖像中。在Windows圖片瀏覽器（電腦）它被旋轉到風景。

上傳前需要對圖像數據應用旋轉變換嗎？那麼我是否還需要刪除在Photoshop和Preview中旋轉它的元數據？

Answer 1

問題在於圖片旋轉被添加到照片中，因爲EXIF數據沒有被大多數瀏覽器使用。有兩種解決方案：

1. 在服務器端應用旋轉。我用的是Ruby的插件回形針（由Thoughtbot），只是必須包括在模型中自動定向轉換選項的has_attached_file命令：

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

2. 旋轉iPhone應用程序中的照片。這在另一個堆棧溢出問題中解決了;調用scaleAndRotate method用@Squeegy替換圖像變換的旋轉元數據。

Answer 2

這裏是CarrierWavew/MiniMagick的解決方案：http://carrierwave.rubyforge.org/rdoc/classes/CarrierWave/MiniMagick.html

Answer 3

一旦你將圖像上傳到服務器之前拍照只是通過您所拍攝的圖像到一個方法和它肯定適合你

#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中以正確的方向保存圖像，以下是手動覆蓋EXIF旋轉元數據的簡單方法。在Windows資源管理器中，右鍵單擊圖像文件並選擇「順時針旋轉」。執行此操作4次以完全旋轉圖像，然後圖像將對所有系統具有正確的方向。然後你可以將圖像上傳到你的網絡服務器。