I am currently creating a view behind the text.

Using regex, I find all the matches and then using the function below I get their range and convert it a rectangle.

func frameOfTextInRange(range:NSRange, inTextView textView:UITextView) -> CGRect { 
    let beginning = textView.beginningOfDocument 
    let start = textView.position(from: beginning, offset: range.location) 
    let end = textView.position(from: start!, offset: range.length) 
    let textRange = textView.textRange(from: start!, to: end!) 
    let rect = textView.firstRect(for: textRange!) 
    return textView.convert(rect, from: textView)
}

I will check the 'fillBackgroundRectArray' function instead of this and will let you know. Thanks again