Swift IOS: Highlight specific character in Text - range

Question

I working with highlighting of particular character in a given text.
Here is my worked code,
let titleLabel: UILabel!
let myText = "கொக்கு"
let textToHighlight = "க்"
titleLabel.frame = CGRect(origin: .zero, size: CGSize(width: 100, height: 100))
let textStroke: [NSAttributedString.Key : Any] = [
.strokeColor : UIColor.white,
.foregroundColor : UIColor.red,
.strokeWidth : -2.0,
]
let textTitle = NSMutableAttributedString(string: myText)
let textHighlightRange = (myText as NSString).range(of: textToHighlight)
textTitle.addAttributes(textStroke, range: textHighlightRange)
titleLabel.attributedText = textTitle
The other Texts which i worked and getting the expected results, but only few words specific in tamil languages am facing issues,
Other Languages Text working fine were,
let myText = "MyText"
let textToHighlight = "T"
let myText = "मानक हिन्दी"
let textToHighlight = "न"
Facing Issues with the text,
let myText = "கொக்கு"
let textToHighlight = "க்"
As i googled and got few details from the link
NSRange in Strings having dialects.
But how to find() and advance() methods used in the given reference.
I am using xcode 11.2 and swift version 4
EDIT:
After a long time, i found a nearest solution to highlight / change foreground color of my matched character in the text as below,
func characterToHighlight(text: String, highlight: String) -> NSAttributedString? {
guard let match = try? NSRegularExpression(pattern: highlight, options: .caseInsensitive) else {
return nil
}
let textStroke: [NSAttributedString.Key : Any] = [
.strokeColor : UIColor.white,
.foregroundColor : UIColor.red,
.strokeWidth : -2.0,
]
let attributedString = NSMutableAttributedString(string: text)
match
.matches(in: text, options: .withTransparentBounds,
range: NSRange(location: 0, length: text.utf16.count))
.forEach {
attributedString.addAttributes(textStroke, range: $0.range)
}
return attributedString
}
if let matchedCharacter = characterToHighlight(text: text, highlight: textToHighlight){titleLabel.attributedText = matchedCharacter}
This code works for the matched character of tamil letters in the string but the foreground of the other letters were black.
I need the non-matched characters in blue color and the matched characters in red color.
How to achieve this?
ANSWER:
let titleLabel: UILabel!
let myText = "கொக்கு"
let textToHighlight = "க்"
titleLabel.frame = CGRect(origin: .zero, size: CGSize(width: 100, height: 100))
let textStroke: [NSAttributedString.Key : Any] = [
.strokeColor : UIColor.white,
.foregroundColor : UIColor.blue,
.strokeWidth : -2.0,
]
let highlightTextAttributes: [NSAttributedString.Key : Any] = [
.strokeColor : UIColor.white,
.foregroundColor : UIColor.red,
.strokeWidth : -4.0,
]
let textTitle = NSMutableAttributedString(string: myText)
textTitle.addAttributes(textStroke, range: textHighlightRange)
if let matchedCharacterRange = getRange(text: text, highlight: textToHighlight)
{
textTitle.addAttributes(highlightTextAttributes, range: matchedCharacterRange)
}
titleLabel.attributedText = textTitle
func getRange(text: String, highlight: String) -> NSRange? {
guard let regex = try? NSRegularExpression(pattern: highlight, options: .caseInsensitive) else {
return nil
}
var highlightRange: NSRange?
regex
.matches(in: text, options: .withTransparentBounds,
range: NSRange(location: 0, length: text.utf16.count))
.forEach {
highlightRange = $0.range
}
return highlightRange
}
I am unable to post my answer separately, so i am editing my question and posting the answer in the same.
Experts, please review and correct me if am wrong.
Thanks for your support.