Question

So I have been at it all day to no luck and it has been needless to say quite frustrating, I have looked up many examples and downloadable categories which all tout being able to crop images flawlessly. Which they do, However the minute i try to do it from an image genrated via AVCaptureSession it does not work as well. I consulted both these sources

http://codefuel.wordpress.com/2011/04/22/image-cropping-from-a-uiscrollview/

http://vocaro.com/trevor/blog/2009/10/12/resize-a-uiimage-the-right-way/

and the project from the first link seems to work directly as advertised but as soon as i hack it to do the same magic on an av capture image…nope…

does anyone have insight into this? Also here is my code for reference.

- (IBAction)TakePhotoPressed:(id)sender 
{
     AVCaptureConnection *videoConnection = nil;
     for (AVCaptureConnection *connection in stillImageOutput.connections)
     {
     for (AVCaptureInputPort *port in [connection inputPorts])
     {
     if ([[port mediaType] isEqual:AVMediaTypeVideo] )
     {
     videoConnection = connection;
     break;
     }
     }
     if (videoConnection) { break; }
     }

     //NSLog(@"about to request a capture from: %@", stillImageOutput);
     [stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error)
     {
         CFDictionaryRef exifAttachments = CMGetAttachment( imageSampleBuffer, kCGImagePropertyExifDictionary, NULL);
         if (exifAttachments)
         {
             // Do something with the attachments.
             //NSLog(@"attachements: %@", exifAttachments);
         }
         else

         NSLog(@"no attachments");

         NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
         UIImage *image = [[UIImage alloc] initWithData:imageData];

         NSLog(@"%f",image.size.width);
         NSLog(@"%f",image.size.height);


         float scale = 1.0f/_scrollView.zoomScale;

         CGRect visibleRect;
         visibleRect.origin.x = _scrollView.contentOffset.x * scale;
         visibleRect.origin.y = _scrollView.contentOffset.x * scale;
         visibleRect.size.width = _scrollView.bounds.size.width * scale;
         visibleRect.size.height = _scrollView.bounds.size.height * scale;

         UIImage* cropped = [self cropImage:image withRect:visibleRect];

         [croppedImage setImage:cropped];         

         [image release];
     }
      ];

    [croppedImage setHidden:NO];


}

cropImage function used above.

-(UIImage*)cropImage :(UIImage*)originalImage withRect :(CGRect) rect
{


    CGRect transformedRect=rect;
    if(originalImage.imageOrientation==UIImageOrientationRight) 
    {
        transformedRect.origin.x = rect.origin.y;
        transformedRect.origin.y = originalImage.size.width-(rect.origin.x+rect.size.width);
        transformedRect.size.width = rect.size.height;
        transformedRect.size.height = rect.size.width;
    }

    CGImageRef cr = CGImageCreateWithImageInRect(originalImage.CGImage, transformedRect);
    UIImage* cropped = [UIImage imageWithCGImage:cr scale:originalImage.scale orientation:originalImage.imageOrientation];
    [croppedImage setFrame:CGRectMake(croppedImage.frame.origin.x, 
                                      croppedImage.frame.origin.y, 
                                      cropped.size.width, 
                                      cropped.size.height)];

    CGImageRelease(cr);
    return cropped;
}

I am also tempted for verbosity and arming whomever might help me in my plight with as much information as possible to post my init of my scrollView and avcapture session. However That may be a bit too much so if you want to see it just ask.

Now as for results of what the code actually does?..

What it looks like before i take the picture

And After…

EDIT:

Well I have a few views now and no comment’s so either no one has figured it out or it’s so simple they thought i would have figured it out again…In any case i have not made any progress. So for anyone interested here is a small sample app with the code all set up and you can see what i am doing

https://docs.google.com/open?id=0Bxr4V3a9QFM_NnoxMkhzZTVNVEE

Answer 1

It seems that this little conundrum did not only have me stumped as after nearly a week,but a scant few of whoever viewed my question had no suggestions either. I must say for this particular problem i could not get it to work in this way, I pondered and tinkered and mused for a while to no avail. Until i did this

[self HideElements];

UIGraphicsBeginImageContext(chosenPhotoView.frame.size);
[chosenPhotoView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

[self ShowElements];

And that’s it, less code and it worked pretty much instantly. So instead of trying to crop an image via the scrollview I take a screenshot of the screen at that time then crop the image using the scrollviews frame variables. And the hide/show element functions hide any overlapping elements on the picture i want.