使用符号特征从*light*字体创建斜体版本

Question

我想要一个浅色字体的斜体版本，例如"HelveticaNeue light"。

使用fontDescriptor可以得到"正则"Helvetica Neue"的斜体版本，而不是斜体的"Helvetiga Neue Light"。我可以检索fontDescriptor.fontAttributes并更新UIFontDescriptor.AttributeName.name，但这很棘手，因为每个字体的命名都不同("HelveticaNeue"使用"Italic"，Helvetica使用"Oblique"(。

let lightFont = UIFont(name: "HelveticaNeue-Light", size: 16.0)!
var lightFontDescriptor = lightFont.fontDescriptor.withSymbolicTraits([.traitItalic])!
var lightFontWithItalicTraits = UIFont(descriptor: lightFontDescriptor, size: 0)
// <UICTFont: ..> font-family: "HelveticaNeue-Light"; font-weight: normal; font-style: normal; font-size: 16.00pt
print(lightFont)
// <UICTFont: ..> font-family: "Helvetica Neue"; font-weight: normal; font-style: italic; font-size: 16.00pt
print(lightFontWithItalicTraits)
// The font I expect:
let lightItalicFont = UIFont(name: "HelveticaNeue-LightItalic", size: 16.0)!
// <UICTFont: ..> font-family: "HelveticaNeue-LightItalic"; font-weight: normal; font-style: italic; font-size: 16.00pt
print(lightItalicFont)

有其他想法如何获得现有字体的斜体版本吗？

Answer 1

它不是最漂亮的，但它很实用。它处理所有内置的iOS字体。

扩展：

extension UIFont {
func italic() -> UIFont? {
if let italic = UIFont.init(name: "(self.fontName)-Italic", size: self.pointSize) {
return italic
} else if let italic = UIFont.init(name: "(self.fontName)Italic", size: self.pointSize) {
return italic
}
if let oblique = UIFont.init(name: "(self.fontName)-Oblique", size: self.pointSize) {
return oblique
} else if let oblique = UIFont.init(name: "(self.fontName)Oblique", size: self.pointSize) {
return oblique
}
var suffixFontName = self.fontName // for font names that have a 2 letter suffix such as ArialMT
suffixFontName.removeLast(2)
let suffix = self.fontName.suffix(2)
if let suffixFontName = UIFont.init(name: "(suffixFontName)-Italic(suffix)", size: self.pointSize) {
return suffixFontName
}
if let suffixFontName = UIFont.init(name: "(suffixFontName)Italic(suffix)", size: self.pointSize) {
return suffixFontName
}
// no italic, oblique, or mt italic font found
return nil
}
}

用法：

let helveticaNeueLightItalic = UIFont(name: "HelveticaNeue-Light", size: 16.0)!.italic()
print(helveticaNeueLightItalic)
let helveticaItalic = UIFont(name: "Helvetica", size: 16.0)!.italic()
print(helveticaItalic)
let helveticaLightItalic = UIFont(name: "Helvetica-Light", size: 16.0)!.italic()
print(helveticaLightItalic)
let arialMtItalic = UIFont(name: "ArialMT", size: 16.0)!.italic()
print(arialMtItalic)
let arialMtBoldItalic = UIFont(name: "Arial-BoldMT", size: 16.0)!.italic()
print(arialMtBoldItalic)