How do I programmatically combine multiple UIImages into one long UIImage? - ios

Question

I'm using the code from here How can I programmatically put together some UIImages to have one big UIImage? to combine multiple screenshots into one large vertical image. However, I'm having trouble calling this function to combine multiple images together using:
imageContainer = [UIImage imageByCombiningImage:imageContainer withImage:viewImage];
How do I call this UIImage+combine category to merge the library of images together?
Here's my Code:
- (void) printScreen {
// this is a method that starts the screenshot taking process
// this line is necessary to capture the completion of the scrollView animation
_webView.scrollView.delegate = self;
// save the first image
UIGraphicsBeginImageContextWithOptions(_webView.bounds.size, NO, 0);
[_webView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);
// scroll to the next section
[_webView.scrollView scrollRectToVisible:CGRectMake(0, _webView.frame.size.height, _webView.frame.size.width, _webView.frame.size.height) animated:YES];
}
- (void )scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView {
// at this point the _webView scrolled to the next section
// I save the offset to make the code a little easier to read
CGFloat offset = _webView.scrollView.contentOffset.y;
UIGraphicsBeginImageContextWithOptions(_webView.bounds.size, NO, 0);
// note that the below line will not work if you replace _webView.layer with _webView.scrollView.layer
[_webView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image1 = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(image1, nil, nil, nil);
// if we are not done yet, scroll to next section
if (offset < _webView.scrollView.contentSize.height) {
[_webView.scrollView scrollRectToVisible:CGRectMake(0, _webView.frame.size.height+offset, _webView.frame.size.width, _webView.frame.size.height) animated:YES];
}
UIImage *image = [UIImage imageByCombiningImage:image1 withImage:image2];
[[self theNewImageView] setImage:image];
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
NSLog(#"%# printScreen Image", image);
NSLog(#"%# printScreen Image2", image2);
}
Edit:
At this point I've tried alot of different things. Im new to objective C development so I've been digging deep into the Apple developer docs and other good places for info like stack and lynda.
Im seeing two different codes from the logs: printScreen Image2, printScreen Image, but i just cant get the function to call the new category.
I'm able to write all the images in separate pieces to the photo album and I can merge image1 or image2 into one image but not the both images or all images.

Answer 1

I figured it out! Right in front of my face the entire time. I needed to add the call to the category within the scrollViewDidEndScrollingAnimation then save to the UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);. I probably tried a couple different version of this solution but I renamed some variables early on to align with my project which screwed everything up.