Display japanese Text with furigana in UILabel

Question

for my app, few month ago, i\'ve take the code from this site to use CTRubyAnnotation.

This code, with few changes to make work with swift 4, work perfectly.

Answer 1

I have same issue.
Your code as Swift4 works correctly on iOS10. It does not function correctly on iOS11.
It seems that there was a change in NSAttributedString of UILabel on iOS 11.
I wrote a general program to draw vertical writing characters in CoreText before. In CoreText, NSAttributedString works on iOS11 as well. Although it is a provisional method, you can avoid this problem by using CoreText.
I written sample code. Since this draws characters directly to context, there is no need for UILabel, but draw with UILabel 's drawText for the moment.

import UIKit

protocol SimpleVerticalGlyphViewProtocol {
}

extension SimpleVerticalGlyphViewProtocol {

    func drawContext(_ attributed:NSMutableAttributedString, textDrawRect:CGRect, isVertical:Bool) {

        guard let context = UIGraphicsGetCurrentContext() else { return }

        var path:CGPath
        if isVertical {
            context.rotate(by: .pi / 2)
            context.scaleBy(x: 1.0, y: -1.0)
            path = CGPath(rect: CGRect(x: textDrawRect.origin.y, y: textDrawRect.origin.x, width: textDrawRect.height, height: textDrawRect.width), transform: nil)
        }
        else {
            context.textMatrix = CGAffineTransform.identity
            context.translateBy(x: 0, y: textDrawRect.height)
            context.scaleBy(x: 1.0, y: -1.0)
            path = CGPath(rect: textDrawRect, transform: nil)
        }

        let framesetter = CTFramesetterCreateWithAttributedString(attributed)
        let frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, attributed.length), path, nil)

        CTFrameDraw(frame, context)
    }
}

And, Use it like below.

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var furiganaLabel: CustomLabel!

    override func viewDidLoad() {
        super.viewDidLoad()
        furiganaLabel.attributedText = Utility.sharedInstance.furigana(String: "｜優勝《ゆうしょう》の｜懸《か》かった｜試合《しあい》。")
    }
}

class CustomLabel: UILabel, SimpleVerticalGlyphViewProtocol {
    //override func draw(_ rect: CGRect) { // if not has drawText, use draw UIView etc
    override func drawText(in rect: CGRect) {
        let attributed = NSMutableAttributedString(attributedString: self.attributedText!)
        let isVertical = false // if Vertical Glyph, true.
        attributed.addAttributes([NSAttributedStringKey.verticalGlyphForm: isVertical], range: NSMakeRange(0, attributed.length))
        drawContext(attributed, textDrawRect: rect, isVertical: isVertical)
    }
}

I added the CustomLabel class which adapted SimpleVerticalGlyphViewProtocol.
Please set the CustomLabel class as UILabel 's Custom Class on Storyboard.

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