Take two images within Camera App - ios

Question

im pretty newish to this kind of coding but have learnt a fair bit and have unfortunately hit a bump in an app im working on.
I am trying to create a camera application that will allow the user to take a 'before' image, then take an 'after' image, I would then like the option for the images to be put together (left and right) and saved as one image.
So far I have managed to code the app to take a single picture with the code below:
HEADER:
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController <UIImagePickerControllerDelegate, UINavigationControllerDelegate>
#property (strong, nonatomic) IBOutlet UIImageView *beforeImage;
- (IBAction)cameraBeforeImage:(UIButton *)sender;
- (IBAction)libraryBeforeImage:(UIButton *)sender;
- (IBAction)deleteBeforeImage:(UIButton *)sender;
#property (strong, nonatomic) IBOutlet UIImageView *afterImage;
- (IBAction)cameraAfterImage:(UIButton *)sender;
- (IBAction)libraryAfterImage:(UIButton *)sender;
- (IBAction)deleteAfterImage:(UIButton *)sender;
- (IBAction)saveImages:(UIButton *)sender;
#end
IMPLEMENTATION:
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)cameraBeforeImage:(UIButton *)sender {
if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
UIAlertView *myAlertView = [[UIAlertView alloc] initWithTitle:#"Oops!"
message:#"This Device Has No Camera, Please Select An Image From Your Library."
delegate:nil
cancelButtonTitle:#"OK"
otherButtonTitles: nil];
[myAlertView show];
}else{
UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.delegate = self;
picker.allowsEditing = YES;
picker.sourceType = UIImagePickerControllerSourceTypeCamera;
[self presentViewController:picker animated:YES completion:NULL];
}
}
- (IBAction)libraryBeforeImage:(UIButton *)sender {
UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.delegate = self;
picker.allowsEditing = YES;
picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
[self presentViewController:picker animated:YES completion:NULL];
}
- (IBAction)deleteAfterImage:(UIButton *)sender {
}
- (IBAction)saveImages:(UIButton *)sender {
}
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
UIImage *chosenImage = info[UIImagePickerControllerEditedImage];
self.beforeImage.image = chosenImage;
[picker dismissViewControllerAnimated:YES completion:NULL];
}
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
[picker dismissViewControllerAnimated:YES completion:NULL];
}
- (IBAction)deleteBeforeImage:(UIButton *)sender {
}
- (IBAction)cameraAfterImage:(UIButton *)sender {
}
- (IBAction)libraryAfterImage:(UIButton *)sender {
}
- (IBAction)saveImages:(UIButton *)sender {
}
#end
Here is the list of things I need to add, any help on any of them would be very much appreciated!
Add the same functionality to the 'After' buttons as the 'Before' but to store the image in the 'afterImage' Image view.
Add functionality to the 'saveImages' button to save the two taken images as one image stitched together.
Thank you all in advance!

Answer 1

1 . The first problem, I guess you question is 'How do you know which picture was taken and where to display it'?
Answer1: Create two UIImagePickerControllers as properties. Once imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info returns an image you can simply check which controller was it if( picker == afterPictureController){....
Answer2: Create a flag indicating whether the next taken picture will be an after or a before picture. It's not very flexible but it works.
2 . To stitch two images, you can create UIGraphicsBeginImageContext with size(image1Width+image2Width, MAX(image1Height, image2Height)) and draw image using the context. After that, you can get the stitched image from the context by calling UIGraphicsGetImageFromCurrentImageContext();