用CGPaths和CAShapeLayers动画绘制字母

我目前正在使用此代码为角色的绘制设置动画:

var path = UIBezierPath()


    var unichars = [UniChar]("J".utf16)
    var glyphs = [CGGlyph](count: unichars.count, repeatedValue: 0)

    let gotGlyphs = CTFontGetGlyphsForCharacters(font, &unichars, &glyphs, unichars.count)
    if gotGlyphs {
        let cgpath = CTFontCreatePathForGlyph(font, glyphs[0], nil)
         path = UIBezierPath(CGPath: cgpath!)

    }

从字符创建bezierpath(在本例中为"J").获取跟踪iOS UIFont中的角色的路径

然后我创建一个CAShapeLayer()并添加动画.

 let layer = CAShapeLayer()
   layer.position = //CGPoint
    layer.bounds = //CGRect()
    view.layer.addSublayer(layer)

    layer.path = path.CGPath

    layer.lineWidth = 5.0
    layer.strokeColor = UIColor.blackColor().CGColor
    layer.fillColor = UIColor.clearColor().CGColor
    layer.geometryFlipped = true

    layer.strokeStart = 0.0
    layer.strokeEnd = 1.0

    let anim = CABasicAnimation(keyPath: "strokeEnd")
    anim.duration = 8.0
    anim.fromValue = 0.0
    anim.toValue = 1.0

    layer.addAnimation(anim, forKey: nil)

结果是我选择的角色正确动画.但是,当我添加另一条路径时path,.appendPath()附加路径会被添加到原始路径上,如您所料.如果我想画一个所有字符都有适当间距等的字母,我该怎么办？感谢您的时间.

您可以使用路径上的转换(使用CGAffineTransformMakeTranslation)来执行此操作,因为路径没有"位置",它只是一组点.但是为了在角色的每次迭代中进行翻译,我们需要路径的当前宽度 - 我们可以使用CGPathGetBoundingBox()它来获取路径将覆盖的框.因此,拥有我们需要的一切,我们可以做一个例子.为整个单词创建一条路径就是这样:

let word = "Test"
let path = UIBezierPath()
let spacing: CGFloat = 50
var i: CGFloat = 0
for letter in word.characters {
    let newPath = getPathForLetter(letter)
    let actualPathRect = CGPathGetBoundingBox(path.CGPath)
    let transform = CGAffineTransformMakeTranslation((CGRectGetWidth(actualPathRect) + min(i, 1)*spacing), 0)
    newPath.applyTransform(transform)
    path.appendPath(newPath)
    i++
}

功能getPathForLetter()只是:

func getPathForLetter(letter: Character) -> UIBezierPath {
    var path = UIBezierPath()
    let font = CTFontCreateWithName("HelveticaNeue", 64, nil)
    var unichars = [UniChar]("\(letter)".utf16)
    var glyphs = [CGGlyph](count: unichars.count, repeatedValue: 0)

    let gotGlyphs = CTFontGetGlyphsForCharacters(font, &unichars, &glyphs, unichars.count)
    if gotGlyphs {
        let cgpath = CTFontCreatePathForGlyph(font, glyphs[0], nil)
        path = UIBezierPath(CGPath: cgpath!)
    }

    return path
}