调整NSMutableAttributedString

Question

我的第一个字符中有一个NSMutableAttributedString +，我想提升2分。

我可以这样说： attributedAmountText.addAttribute(NSKernAttributeName, value: 2.0, range: NSRange(location: 0, length: 1))

有没有办法解除第一个角色？有点像垂直kern

编辑：

尝试attributedAmountText.addAttribute(NSBaselineOffsetAttributeName, value: 2.0, range: NSRange(location: 0, length: 1))实际上会移动基线本身而不是垂直离开基线的文本，这似乎很奇怪，因为文档说不然：

  

此属性的值是一个NSNumber对象，其中包含一个浮点值，指示角色与基线的偏移量（以磅为单位）。默认值为0.

Answer 1

嗯......快速测试一下这段代码：

class ScalingViewController: UIViewController {

    @IBOutlet weak var theLabel: UILabel!

    @IBOutlet weak var theOtherLabel: UILabel!

    let now = Date()

    let labelA: UILabel = {
        let v = UILabel()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = UIColor.cyan
        return v
    }()

    let labelB: UILabel = {
        let v = UILabel()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = UIColor.yellow
        return v
    }()

    let labelC: UILabel = {
        let v = UILabel()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = UIColor.green
        return v
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        view.addSubview(labelA)
        view.addSubview(labelB)
        view.addSubview(labelC)

        labelA.topAnchor.constraint(equalTo: view.topAnchor, constant: 40.0).isActive = true
        labelA.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 8.0).isActive = true

        labelB.topAnchor.constraint(equalTo: labelA.topAnchor, constant: 0.0).isActive = true
        labelB.leadingAnchor.constraint(equalTo: labelA.trailingAnchor, constant: 8.0).isActive = true

        labelC.topAnchor.constraint(equalTo: labelA.topAnchor, constant: 0.0).isActive = true
        labelC.leadingAnchor.constraint(equalTo: labelB.trailingAnchor, constant: 8.0).isActive = true

        var aText = NSMutableAttributedString()
        let baseFont = UIFont.systemFont(ofSize: 30.0, weight: UIFontWeightLight)


        let testString = "Example"
        let tsLength = testString.characters.count


        // Font only
        aText = NSMutableAttributedString()
        aText.append(NSMutableAttributedString(string: testString, attributes: [NSFontAttributeName: baseFont]))

        labelA.attributedText = aText


        // Font + positive Baseline Offset of 1st character
        aText = NSMutableAttributedString()
        aText.append(NSMutableAttributedString(string: testString, attributes: [NSFontAttributeName: baseFont]))
        aText.addAttribute(NSBaselineOffsetAttributeName, value: 10.0, range: NSRange(location: 0, length: 1))

        labelB.attributedText = aText


        // Font + negative Baseline Offset of all but 1st character
        aText = NSMutableAttributedString()
        aText.append(NSMutableAttributedString(string: testString, attributes: [NSFontAttributeName: baseFont]))
        aText.addAttribute(NSBaselineOffsetAttributeName, value: -10.0, range: NSRange(location: 1, length: tsLength - 1))

        labelC.attributedText = aText

    }

}

给我这个结果：

我想如果我对String属性的所有排版方面有足够的了解，这会有意义吗？