Question

我正在使用以下代码将图像发送到Web服务器。它的工作原理是，图像在上传后因某种原因而被旋转。

这是我的上传方法：

 - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

        [self dismissViewControllerAnimated:YES completion:nil];

        NSData *image = UIImageJPEGRepresentation([info objectForKey:UIImagePickerControllerOriginalImage], 0.1);

        // use token with url for json data from contents of url
        NSString *savedValue = [[NSUserDefaults standardUserDefaults]
                                stringForKey:@"token"];

        NSString *urlString = [NSString stringWithFormat:@"%@%@/photos?token=%@", kIDURLPhoto, listingId, savedValue];

        NSLog(@"urlstring for comment is %@",urlString);

        self.flUploadEngine = [[fileUploadEngine alloc] initWithHostName:urlString customHeaderFields:nil];

        NSMutableDictionary *postParams = [NSMutableDictionary dictionaryWithObjectsAndKeys: @"image", @"caption", nil];

        self.flOperation = [self.flUploadEngine postDataToServer:postParams path:nil];
        [self.flOperation addData:image forKey:@"picture" mimeType:@"image/jpeg" fileName:@"upload.jpg"];

        [self.flOperation addCompletionHandler:^(MKNetworkOperation* operation) {
            NSLog(@"%@", [operation responseString]);

    //         handle a successful 200 response

        [self.flUploadEngine enqueueOperation:self.flOperation];

        // for iOS7
        if ([self respondsToSelector:@selector(setNeedsStatusBarAppearanceUpdate)]) {

            [[UIApplication sharedApplication] setStatusBarHidden:YES];
        }

        [self forceReload];

    }

Answer 1

目标C代码：

-(UIImage *)scaleAndRotateImage:(UIImage *)image{
        // No-op if the orientation is already correct
        if (image.imageOrientation == UIImageOrientationUp) return image;

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

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

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

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

            case UIImageOrientationLeftMirrored:
            case UIImageOrientationRightMirrored:
                transform = CGAffineTransformTranslate(transform, image.size.height, 0);
                transform = CGAffineTransformScale(transform, -1, 1);
                break;
            case UIImageOrientationUp:
            case UIImageOrientationDown:
            case UIImageOrientationLeft:
            case UIImageOrientationRight:
                break;
        }

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

            default:
                CGContextDrawImage(ctx, CGRectMake(0,0,image.size.width,image.size.height), image.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;
}

使用代码

 UIImage *img=[info objectForKey:UIImagePickerControllerOriginalImage];

 img=[self scaleAndRotateImage:img];
 NSData *image = UIImageJPEGRepresentation(img, 0.1);

Answer 2

很可能你没有考虑exif数据，他们给出了相机的旋转，你应该将它们添加到图像EXIF字典中。这样，当您打开图像时，阅读软件可以相应地旋转图像。检查此question and relative answers，这将有所帮助

上传到服务器的iOS UIImage被旋转

2 个答案: