NSLayoutManager隐藏新行字符不管我做什么

我试图在我的NSTextView子类中显示不可见字符，如新行字符。像重写NSLayoutManager的drawGlyph方法这样的常用方法是一个坏主意，因为它太慢，并且不适合多页面布局。NSLayoutManager隐藏新行字符不管我做什么

我想要做的是重写NSLayoutManager的setGlyph方法，以便用“¶”字形替换不可见的“\ n”字形并用“∙”替换“”。

它对“”空格字形起作用，但对新行字符没有影响。

public override func setGlyphs(_ glyphs: UnsafePointer<CGGlyph>, properties props: UnsafePointer<NSGlyphProperty>, characterIndexes charIndexes: UnsafePointer<Int>, font aFont: Font, forGlyphRange glyphRange: NSRange) { 
    var substring = (self.currentTextStorage.string as NSString).substring(with: glyphRange) 

    // replace invisible characters with visible 
    if PreferencesManager.shared.shouldShowInvisibles == true { 
     substring = substring.replacingOccurrences(of: " ", with: "\u{00B7}") 
     substring = substring.replacingOccurrences(of: "\n", with: "u{00B6}") 
    } 

    // create a CFString 
    let stringRef = substring as CFString 
    let count = CFStringGetLength(stringRef) 

    // convert processed string to the C-pointer 
    let cfRange = CFRangeMake(0, count) 
    let fontRef = CTFontCreateWithName(aFont.fontName as CFString?, aFont.pointSize, nil) 
    let characters = UnsafeMutablePointer<UniChar>.allocate(capacity: MemoryLayout<UniChar>.size * count) 
    CFStringGetCharacters(stringRef, cfRange, characters) 

    // get glyphs for the pointer of characters 
    let glyphsRef = UnsafeMutablePointer<CGGlyph>.allocate(capacity: MemoryLayout<CGGlyph>.size * count) 
    CTFontGetGlyphsForCharacters(fontRef, characters, glyphsRef, count) 

    // set those glyphs 
    super.setGlyphs(glyphsRef, properties:props, characterIndexes: charIndexes, font: aFont, forGlyphRange: glyphRange) 
}

于是我想出了一个主意：它看起来像NSTypesetter标志着新行字符范围像那些它不应该处理的。因此，我将NSTypesetter分类并重写了一种方法：

override func setNotShownAttribute(_ flag: Bool, forGlyphRange glyphRange: NSRange) { 
    let theFlag = PreferencesManager.shared.shouldShowInvisibles == true ? false : true 
    super.setNotShownAttribute(theFlag, forGlyphRange: glyphRange) 
}

但它不起作用。无论我创建的是什么字形，NSLayoutManager仍然不会为新行字符生成字形。

我在做什么错？

来源

2016-09-17 Vitaliy Vashchenko

正如我所知，该类的NSTypesetter的setNotShownAttribute：的默认实现不会更改其字形存储中已经生成的字形。所以，超级通话不会产生任何效果。我只需在调用super之前手动替换字形。

因此，最有效的实现显示不可见的字符的（你会看到其中的差别，而缩放视图）是这样的：

这种方法的

限制：如果您的应用可以在文本视图多种字体，那么这种方法可能不是一个好主意，因为那些显示不可见字符的字体也会不同。这不是你想要达到的。

子类NSLayoutManager并重写setGlyphs展示空间字符：

public override func setGlyphs(_ glyphs: UnsafePointer<CGGlyph>, properties props: UnsafePointer<NSGlyphProperty>, characterIndexes charIndexes: UnsafePointer<Int>, font aFont: Font, forGlyphRange glyphRange: NSRange) { 
    var substring = (self.currentTextStorage.string as NSString).substring(with: glyphRange) 

    // replace invisible characters with visible 
    if PreferencesManager.shared.shouldShowInvisibles == true { 
     substring = substring.replacingOccurrences(of: " ", with: "\u{00B7}") 
    } 

    // create a CFString 
    let stringRef = substring as CFString 
    let count = CFStringGetLength(stringRef) 

    // convert processed string to the C-pointer 
    let cfRange = CFRangeMake(0, count) 
    let fontRef = CTFontCreateWithName(aFont.fontName as CFString?, aFont.pointSize, nil) 
    let characters = UnsafeMutablePointer<UniChar>.allocate(capacity: MemoryLayout<UniChar>.size * count) 
    CFStringGetCharacters(stringRef, cfRange, characters) 

    // get glyphs for the pointer of characters 
    let glyphsRef = UnsafeMutablePointer<CGGlyph>.allocate(capacity: MemoryLayout<CGGlyph>.size * count) 
    CTFontGetGlyphsForCharacters(fontRef, characters, glyphsRef, count) 

    // set those glyphs 
    super.setGlyphs(glyphsRef, properties:props, characterIndexes: charIndexes, font: aFont, forGlyphRange: glyphRange) 
}

子类NSATSTypesetter并将其分配给您的NSLayoutManager subclas。子类将显示新行字符，并确保每一个无形的字符将用不同的颜色来绘制：

class CustomTypesetter: NSATSTypesetter { 

    override func setNotShownAttribute(_ flag: Bool, forGlyphRange glyphRange: NSRange) { 
     var theFlag = flag 

     if PreferencesManager.shared.shouldShowInvisibles == true { 
      theFlag = false 

      // add new line glyphs into the glyph storage 
      var newLineGlyph = yourFont.glyph(withName: "paragraph") 
      self.substituteGlyphs(in: glyphRange, withGlyphs: &newLineGlyph) 

      // draw new line char with different color 
      self.layoutManager?.addTemporaryAttribute(NSForegroundColorAttributeName, value: NSColor.invisibleTextColor, forCharacterRange: glyphRange) 
     } 

     super.setNotShownAttribute(theFlag, forGlyphRange: glyphRange) 
    } 

    /// Currently hadn't found any faster way to draw space glyphs with different color 
    override func setParagraphGlyphRange(_ paragraphRange: NSRange, separatorGlyphRange paragraphSeparatorRange: NSRange) { 
     super.setParagraphGlyphRange(paragraphRange, separatorGlyphRange: paragraphSeparatorRange) 

     guard PreferencesManager.shared.shouldShowInvisibles == true else { return } 

     if let substring = (self.layoutManager?.textStorage?.string as NSString?)?.substring(with: paragraphRange) { 
      let expression = try? NSRegularExpression.init(pattern: "\\s", options: NSRegularExpression.Options.useUnicodeWordBoundaries) 
      let sunstringRange = NSRange(location: 0, length: substring.characters.count) 

      if let matches = expression?.matches(in: substring, options: NSRegularExpression.MatchingOptions.withoutAnchoringBounds, range: sunstringRange) { 
       for match in matches { 
        let globalSubRange = NSRange(location: paragraphRange.location + match.range.location, length: 1) 
        self.layoutManager?.addTemporaryAttribute(NSForegroundColorAttributeName, value: Color.invisibleText, forCharacterRange: globalSubRange) 
       } 
      } 
     } 
    } 
}

要显示/隐藏不可见的字符只要致电：

let storageRange = NSRange(location: 0, length: currentTextStorage.length) 
layoutManager.invalidateGlyphs(forCharacterRange: storageRange, changeInLength: 0, actualCharacterRange: nil) 
layoutManager.ensureGlyphs(forGlyphRange: storageRange)

来源

2016-09-17 16:18:24

似乎这段代码在Swift3中，我们如何将它转换成Swift 2.3？我注意到Swift 2.3中没有“MemoryLayout”。 –

NSLayoutManager隐藏新行字符不管我做什么

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