How do I load an image from the photo roll and add other images from the roll on top of it, possibly sort it, and save the final product?

Question

I'm trying to make some composite images from currently existing ones in the photo rolls. I have code that seems to work that loads an image from the photo roll onto a UIImageView and displays it to the user; (here's the Action that does that:)

- (IBAction)grabImage:(id)sender
{
    if ([_myPopoverController isPopoverVisible])
        [_myPopoverController dismissPopoverAnimated:YES];
     else
    {
        if ([UIImagePickerController isSourceTypeAvailable: UIImagePickerControllerSourceTypeSavedPhotosAlbum])
        {
            UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
            imagePicker.delegate = self;
            imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
            imagePicker.mediaTypes = [NSArray arrayWithObjects: (NSString *) kUTTypeImage, nil];
            imagePicker.allowsEditing = NO;
            _myPopoverController = [[UIPopoverController alloc] initWithContentViewController:imagePicker];
            _myPopoverController.delegate = self;
            [_myPopoverController presentPopoverFromRect: [sender frame] inView:self.view permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES ];
            _newMedia = NO;
        }
    }
}

next I want to be able to select more photos, but instead of replacing the current one I want them to be layered one on top of another. Finally, when the user is done layering images, I want them to be able to save the final product to the photo roll.

How do I implement this? Not sure where to start...

thanks in advance,

marina

score 0 · Answer 1 · answered May 08 '13 at 19:21

It turns out that all that was needed to do this is just add CALayers to an UIImageView with various degrees of alpha; instead of wiping out the previous image and replacing it with a new one, I simply add differently alpha's layers of images. Works like a charm!

How do I load an image from the photo roll and add other images from the roll on top of it, possibly sort it, and save the final product?

1 Answers1