Stitch/Composite multiple images vertically and save as one image (iOS, objective-c)

Question

I need help writing an objective-c function that will take in an array of UIImages/PNGs, and return/save one tall image of all the images stitched together in order vertical

Answer 1

The solutions above were helpful but had a serious flaw for me. The problem is that if the images are of different sizes, the resulting stitched image would have potentially large spaces between the parts. The solution I came up with combines all images right below each other so that it looks like more like a single image no matter the individual image sizes.

For Swift 3.x

static func combineImages(images:[UIImage]) -> UIImage
{
    var maxHeight:CGFloat = 0.0
    var maxWidth:CGFloat = 0.0

    for image in images
    {
        maxHeight += image.size.height
        if image.size.width > maxWidth
        {
            maxWidth = image.size.width
        }
    }

    let finalSize = CGSize(width: maxWidth, height: maxHeight)

    UIGraphicsBeginImageContext(finalSize)

    var runningHeight: CGFloat = 0.0

    for image in images
    {
        image.draw(in: CGRect(x: 0.0, y: runningHeight, width: image.size.width, height: image.size.height))
        runningHeight += image.size.height
    }

    let finalImage = UIGraphicsGetImageFromCurrentImageContext()

    UIGraphicsEndImageContext()

    return finalImage!
}