ios - 如何在包含 View 的旋转变换期间保持文本水平

Question

制作自定义 UI 控件(例如旋转轮)，如下所示:

正如您所看到的，标签定位在“半径上”，但我需要水平放置所有标签，并在旋转容器 View 时保持相同的方式

Answer 1

你可以这样做:

    let font = UIFont.systemFont(ofSize: 12)
    let attributes = [
        NSAttributedString.Key.font: UIConstants.CaptionFont,
        NSAttributedString.Key.foregroundColor: UIColor.accent
    ]

    for path in pathsForIndicators {
        let cgPath = path.cgPath
        let layer = CATextLayer()
        layer.frame = CGRect(x: cgPath.boundingBox.midX + offset + 22,
                             y: cgPath.boundingBox.midX + 10, width: 40, height: 40)
        layer.position = CGPoint(x: cgPath.boundingBox.midX + offset + 22,
                                 y: cgPath.boundingBox.midY + 10)
        layer.font = font
        let value = 0 // TODO
        let title = String(describing: value)
        let attributedString = NSAttributedString(string: title, attributes: attributes)
        layer.string = attributedString
        layer.isWrapped = false
        layer.alignmentMode = CATextLayerAlignmentMode.center
        layer.foregroundColor = indicatorColor.cgColor
        layer.shouldRasterize = true
        layer.needsDisplayOnBoundsChange = false
        layer.needsDisplay()
        layer.displayIfNeeded()
        textLayer.addSublayer(layer)
    }
    textLayer.backgroundColor = UIColor.clear.cgColor
    textLayer.bounds = bounds
    textLayer.position = centerPoint
    layer.addSublayer(textLayer)