稍微弯曲CATextLayer

如何解决稍微弯曲CATextLayer

尝试弯曲一些文本。我正在尝试修改Curve text on existing circle，但不能在圆的上下文中使用它，而只是在一条直线上进行，但是老实说，我不确定我是否完全了解该代码在做什么以进行修改

这是我正在进行的代码段：

extension CALayer {
    
    func drawCurvedString(text: NSAttributedString,angle: CGFloat,radius: CGFloat) {
        var radAngle = angle.radians
        
        let textSize = text.boundingRect(
            with: CGSize(width: .max,height: .max),options: [.usesLineFragmentOrigin,.usesFontLeading],context: nil)
            .integral
            .size
        
        let perimeter: CGFloat = 2 * .pi * radius
        let textAngle: CGFloat = textSize.width / perimeter * 2 * .pi
        
        var textRotation: CGFloat = 0
        var textDirection: CGFloat = 0
        
        if radAngle > CGFloat(10).radians,radAngle < CGFloat(170).radians {
            // bottom string
            textRotation = 0.5 * .pi
            textDirection = -2 * .pi
            radAngle += textAngle / 2
        } else {
            // top string
            textRotation = 1.5 * .pi
            textDirection = 2 * .pi
            radAngle -= textAngle / 2
        }
        
        for c in 0..<text.length {
            let letter = text.attributedSubstring(from: NSRange(c..<c+1))
            let charSize = letter.boundingRect(
                with: CGSize(width: .max,context: nil)
                .integral
                .size
            
            let letterangle = (charSize.width / perimeter) * textDirection
            let x = charSize.width * CGFloat(c)//radius * cos(radAngle + (letterangle / 2))
            let y: CGFloat = 0//radius * sin(radAngle + (letterangle / 2))
            
            print("x:\(x),y: \(y)")
            
            let singleChar = drawText(
                text: letter,frame: CGRect(
                    x: (self.frame.size.width / 2) - (charSize.width / 2) + x,y: (self.frame.size.height / 2) - (charSize.height / 2) + y,width: charSize.width,height: charSize.height))
            self.addSublayer(singleChar)
            singleChar.transform = CATransform3DMakeAffineTransform(CGAffineTransform(rotationAngle: radAngle - textRotation))
            radAngle += letterangle
        }
    }
    
    
    func drawText(text: NSAttributedString,frame: CGRect) -> CATextLayer {
        let textLayer = CATextLayer()
        textLayer.frame = frame
        textLayer.string = text
        textLayer.alignmentMode = CATextLayerAlignmentMode.center
        textLayer.contentsScale = UIScreen.main.scale
        return textLayer
    }
} 

导致这种可怕的事情：