iphone：从相机拍摄的图像改变方向

Question

我制作了一个 iphone 应用程序来从相机捕获图像并将该图像设置在下一个视图中。但问题是图像被旋转了。即风景图像变成potraite，protraite图像变成风景。 我参考了很多代码，但无法解决。

我的代码是：

- (void)btnCapturePressed
{
 if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
        {

            picker=[[UIImagePickerController alloc] init];
            picker.delegate=self;

            [picker setAllowsEditing:YES];

            picker.sourceType=UIImagePickerControllerSourceTypeCamera;
            //[self.navigationController pushViewController:(UIViewController *)ipc animated:YES];
            [self presentModalViewController:picker animated:YES];
            [picker release];
      }
}

-(void) imagePickerController:(UIImagePickerController *) picker didFinishPickingMediaWithInfo :(NSDictionary *)info
{
           UIImage *imageToScale=[info objectForKey:UIImagePickerControllerOriginalImage];

            imgView = [[UIImageView alloc] initWithImage:imageToScale];

            [picker presentModalViewController:cropper animated:YES];
}

我还提到了link。有同样的问题，但找不到解决方案。

请帮帮我。

谢谢。

Answer 1

因此，在拍摄图像时，存储设备的方向并将其作为参数传递给下面的方法 这里只需给方法起任何名称并传递参数orientation

switch (orientation) {
            case UIDeviceOrientationPortrait:
                [featureLayer setAffineTransform:CGAffineTransformMakeRotation(DegreesToRadians(0.))];
                break;
            case UIDeviceOrientationPortraitUpsideDown:
                [featureLayer setAffineTransform:CGAffineTransformMakeRotation(DegreesToRadians(180.))];
                break;
            case UIDeviceOrientationLandscapeLeft:
                [featureLayer setAffineTransform:CGAffineTransformMakeRotation(DegreesToRadians(90.))];
                break;
            case UIDeviceOrientationLandscapeRight:
                [featureLayer setAffineTransform:CGAffineTransformMakeRotation(DegreesToRadians(-90.))];
                break;
            case UIDeviceOrientationFaceUp:
            case UIDeviceOrientationFaceDown:
            default:
                break; // leave the layer in its last known orientation
        }

我在这里使用的宏DegreesToRadians()如下

static CGFloat DegreesToRadians(CGFloat degrees) {return degrees * M_PI / 180;};

这肯定行得通。

快乐编码:)

编辑

如果上面的代码不能正常工作，那就用这个

@interface UIImage (RotationMethods)
- (UIImage *)imageRotatedByDegrees:(CGFloat)degrees;
@end

@implementation UIImage (RotationMethods)

- (UIImage *)imageRotatedByDegrees:(CGFloat)degrees 
{   
    // calculate the size of the rotated view's containing box for our drawing space
    UIView *rotatedViewBox = [[UIView alloc] initWithFrame:CGRectMake(0,0,self.size.width, self.size.height)];
    CGAffineTransform t = CGAffineTransformMakeRotation(DegreesToRadians(degrees));
    rotatedViewBox.transform = t;
    CGSize rotatedSize = rotatedViewBox.frame.size;

    // Create the bitmap context
    UIGraphicsBeginImageContext(rotatedSize);
    CGContextRef bitmap = UIGraphicsGetCurrentContext();

    // Move the origin to the middle of the image so we will rotate and scale around the center.
    CGContextTranslateCTM(bitmap, rotatedSize.width/2, rotatedSize.height/2);

    //   // Rotate the image context
    CGContextRotateCTM(bitmap, DegreesToRadians(degrees));

    // Now, draw the rotated/scaled image into the context
    CGContextScaleCTM(bitmap, 1.0, -1.0);
    CGContextDrawImage(bitmap, CGRectMake(-self.size.width / 2, -self.size.height / 2, self.size.width, self.size.height), [self CGImage]);

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;

}
@end

然后调用上面的函数如下

switch (orientation) {
        case UIDeviceOrientationPortrait:
            image = [image imageRotatedByDegrees:0];
            break;
        case UIDeviceOrientationPortraitUpsideDown:
            image = [image imageRotatedByDegrees:180];
            break;
        case UIDeviceOrientationLandscapeLeft:
            image = [image imageRotatedByDegrees:-90];
            break;
        case UIDeviceOrientationLandscapeRight:
            image = [image imageRotatedByDegrees:90];
            break;
        case UIDeviceOrientationFaceUp:
        case UIDeviceOrientationFaceDown:
        default:
            break; // leave the layer in its last known orientation
    }   

如果图像不是所需的方向，则将 90 添加到上述所有 imageRotatedByDegrees 的参数（即，如果它是 0，那么它将是 0+90）或根据您的需要。

编辑 1

UIDeviceOrientation curDeviceOrientation = [[UIDevice currentDevice] orientation];

Answer 2

我一直在努力解决这个问题，但找到了一个更简单的解决方案：

  AVCaptureConnection *vc = [self.snapper connectionWithMediaType:AVMediaTypeVideo];

  // THIS IS THE KEY LINE!!!!!!!!!!!!!!!!!!!!!
  [vc setVideoOrientation:[self interfaceToVideoOrientation]];

  [self.snapper captureStillImageAsynchronouslyFromConnection:vc
                                            completionHandler:
   ^(CMSampleBufferRef buf, NSError *err) {
     NSData* data = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:buf];
     UIImage* im = [UIImage imageWithData:data];
     // Do something with the image.
  }];


- (AVCaptureVideoOrientation)interfaceToVideoOrientation
{
  switch ([UIApplication sharedApplication].statusBarOrientation)
  {
    case UIInterfaceOrientationPortrait:
      return AVCaptureVideoOrientationPortrait;
    case UIInterfaceOrientationPortraitUpsideDown:
      return AVCaptureVideoOrientationPortraitUpsideDown;
    case UIInterfaceOrientationLandscapeRight:
      return AVCaptureVideoOrientationLandscapeRight;
    case UIInterfaceOrientationLandscapeLeft:
      return AVCaptureVideoOrientationLandscapeLeft;
    default:
      return AVCaptureVideoOrientationPortrait;
  }
}

在捕获之前设置视频方向现在解决了我的图像以错误方向显示的问题。

Answer 3

我有同样的问题，这对我有帮助。希望它也能帮助你。我花了 2 分钟来解决这个问题。 http://xcodetipss.blogspot.com/2012/04/image-rotated-when-taken-from-camera.html

Answer 4

我参考了苹果论坛（https://discussions.apple.com/thread/1537011?start=0&tstart=0）的讨论并找到了以下解决方案；它对我来说非常有效；我只是复制粘贴它，它就像宝石一样工作；

-(UIImage *) scaleAndRotateImage(UIImage *)image
{
 int kMaxResolution = 320; // 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 = bounds.size.width / ratio;
 }
 else {
 bounds.size.height = kMaxResolution;
 bounds.size.width = 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;
}