How to crop UIImagePickerController taken picture as it is on display

Question

When I take photo using UIImagePickerController, there is more picture than was visible on screen... How can I take photo/crop it, so that it's exactly the same as I saw on screen?

edit: I'll add code, to specify my problem:

- (void)showImagePickerForSourceType:(UIImagePickerControllerSourceType)sourceType
{

UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
imagePickerController.modalPresentationStyle = UIModalPresentationCurrentContext;
imagePickerController.sourceType = sourceType;
imagePickerController.delegate = self;
imagePickerController.showsCameraControls = NO;
imagePickerController.allowsEditing = YES;

if (sourceType == UIImagePickerControllerSourceTypeCamera)
{
    [[NSBundle mainBundle] loadNibNamed:@"OverlayView" owner:self options:nil];
    self.overlayView.frame = imagePickerController.cameraOverlayView.frame;
    imagePickerController.cameraOverlayView = self.overlayView;
    //self.overlayView = nil;
    self.overlayImage.image = self.imageView.image;
    self.overlayImage.alpha = 0.5;

    UISlider *slider=[[UISlider alloc]initWithFrame:CGRectMake(60, 80, 200, 30)];
    [slider setMaximumValue:1.0];
    [slider setMinimumValue:0.0];
    [slider setValue:0.5];
    [slider addTarget:self action:@selector(sliderChanged:)  forControlEvents:UIControlEventValueChanged];

    if (self.working == TRUE)
    {
        [imagePickerController.cameraOverlayView addSubview:self.overlayImage];
        [imagePickerController.cameraOverlayView addSubview:slider];
    }
}

self.imagePickerController = imagePickerController;
[self presentViewController:self.imagePickerController animated:YES completion:nil];
}

didFinishPickingMediaWithInfo:

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
[self dismissViewControllerAnimated:YES completion:NULL];

//this works, image is displayed
UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
//this doesn't work, image is nil
UIImage *image = [info objecyForKey:UIImagePickerControllerEditedImage];    

[self.imageView setImage:image];
self.working = TRUE;

self.imagePickerController = nil;
//[self dismissViewControllerAnimated:YES completion:NULL];
}

Can I use UIImagePickerControllerEditedImage, when imagePickerController.showsCameraControls = NO;?

Solution 1

Just posting this as an answer, but I am not sure if the poster asks for the edited image.

When you take a picture with the UIImagePickerController, the picker shows only part of the image that is actually captured when taking the photo, like shown in the picture below where the black lines are the screen of the iPhone.

The image you get from the camera is the full size image, but on screen is only the center of the image, with either the width or the height of the image maxed out to the screen size.

All you need to do is get the center from the image like shown above and you have the exact image you had on your screen.

Solution 2

You can get the original or cropped image depending on the key for info dictionary.

The pickedImageEdited would be the cropped image you are looking for and pickedImageOriginal would be the full original image.

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

    UIImage *pickedImageEdited = [info objectForKey:UIImagePickerControllerEditedImage];

    //do your stuff

    [self dismissViewControllerAnimated:YES completion:nil];
}

Solution 3

After Wim's answer, I was able to come up with solution like this:

UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];

UIGraphicsBeginImageContext(CGSizeMake(720, 960));
[image drawInRect: CGRectMake(0, 0, 720, 960)];
UIImage *smallImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

CGRect cropRect = CGRectMake(40, 0, 640, 960);

CGImageRef imageRef = CGImageCreateWithImageInRect([smallImage CGImage], cropRect);
[self.imageView setImage:[UIImage imageWithCGImage:imageRef]];

As you can see, this is made for 3,5" iPhone screen, and it seems to work, but code is device-dependent, or is there better solution?

Comments

[Adam Bardon]

thanks for reply, I've tried to use UIImagePickerControllerEditedImage, then I'll assign it to UIImageView so I can display it, but for some reason when showing that imageView, app crashes... whereas when I'm using UIImagePickerControllerOriginalImage it works ok

[Rok Jarc]

Do you have some more crash information? Do you have controller's allowsEditing set to YES? I use this code in many apps with no problems whatsoever.

[Rok Jarc]

App shouldn't crash even if edited image was nil so there is probably a problem elsewhere in the code.

[Adam Bardon]

allowsEditing is set to YES, and UIImagePickerControllerEditedImage is nil

[Rok Jarc]

Do you by any chance dismiss the controller before you set the image?

[Adam Bardon]

I dismiss the controller at the end of didFInishPIckingMediaWithInfo method (which is basically the one from apple's sample code, just slightly edited)

[Rok Jarc]

Strange. Try expanding your question a bit, post some code (possibly with exact crash location).

[Adam Bardon]

ok, my bad, crash was caused most probably by UIImage *image = [info valueForKey:UIImagePickerControllerEditedImage]; [self.capturedImages addObject:image];

[Adam Bardon]

thanks for help :) I've used apple's sample code, and left few things as it was, even though I didn't needed it, so that was a mistake... anyway now when I assign UIImagePickerControllerOriginalImage to UIImage, nothing is displayed... is it possible that it'd be nil?

[Rok Jarc]

it shouldn't be nil. you can always check with if (![info objectForKey:UIImagePickerControllerOriginalImage]) NSLog (@"it's NIL"); but probably your IBOutlet (if you use IB) is not properly connected or you don't assign the new image to some UIImageView object.image or the UIImageView object is not added to the viewcontroller's view.

[Adam Bardon]

when I use UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage]; it works perfectly, so everything should be set ok, after changing to UIImage *image = [info valueForKey:UIImagePickerControllerEditedImage]; image is not displayed

[Rok Jarc]

check this answer: stackoverflow.com/a/4192109/653513 seems crazy but it might work

[Adam Bardon]

even using ALAssetsLibrary as was suggested on that above answer, it doesn't work for me, strange is that they have troubles on simulator, whereas I'm testing it on real device iphone 4s...

[Rok Jarc]

Have you tried dismissing picker before taking the image from info. That is suggested in the linked answer.

[Adam Bardon]

from linked answer: The other option that almost assuredly will work is to create a separate file for the image picking code in Xcode and set that file to not use ARC, keeping the solution here. could you give me code how to do that?

[Adam Bardon]

Hi Wim, thank you for your answer, that's exactly what I was asking for :)

[Wim Haanstra]

Great, you should mark it as the answer, so that other people can find it.

[Adam Bardon]

Well, adjust the size based on the device.