无论我做什么，NSLayoutManager 都会隐藏换行符 [英] NSLayoutManager hides new line characters no matter what I do
问题描述
我试图在我的 NSTextView 子类中显示不可见的字符，比如换行符.像覆盖 NSLayoutManager 的 drawGlyph 方法这样的常用方法是一个坏主意，因为它太慢并且不能在多页布局中正常工作.
I'm trying to show invisible characters like the new line character in my NSTextView subclass. The usual approach like overriding drawGlyph method of NSLayoutManager is a bad idea because it's too slow and not work properly with multi-paged layout.
我想要做的是覆盖 NSLayoutManager 的 setGlyph 方法，以便它将不可见的\n"字形替换为¶"字形，将"替换为∙".
What I'm trying to do is to override the setGlyph method of the NSLayoutManager so it would replace invisible "\n" glyph with "¶" glyph and " " with "∙".
它适用于 " " 空格字形，但对换行符没有影响.
And it works on the " " space glyphs but has no effect on the new line characters.
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)
}
然后我想出了一个主意:它看起来像 NSTypesetter 标记了新的行字符范围，就像它根本不应该处理的那样.所以我继承了 NSTypesetter 并重写了一个方法:
Then I came up with an idea: it looks like NSTypesetter marks new line char ranges like those it shouldn't process at all. So I subclassed NSTypesetter and did override a method:
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.无论我创建什么字形，NSLayoutManager 仍然不会为新行字符生成字形.
But it's not working. NSLayoutManager still won't generate a glyph for the new line character, no matter what glyph I create.
我做错了什么?
推荐答案
据我所知，类的 NSTypesetter 的 setNotShownAttribute: 的默认实现不会更改其字形存储中已生成的字形.所以，调用 super 不会产生任何效果.我只需要在调用 super 之前手动替换字形.
As I figured out, the default implementation of NSTypesetter's setNotShownAttribute: of the class doesn't change already generated glyphs in its glyph storage. So, call of super doesn't produce any effect. I just have to replace glyphs manually before calling super.
因此，显示不可见字符(缩放视图时您会看到差异)的最有效实现是这样的:
So, the most efficient implementation of showing invisible characters (you will see the difference while zooming the view) is this:
这种方法的局限性:如果你的应用程序必须在文本视图中有多种字体，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会有所不同好.这不是您可能想要实现的目标.
Limitations of this approach: if your app has to have multiple fonts in text view, then this approach might not be such a good idea, because the font of those displayed invisible characters will be different as well. And that's not what you might want to achieve.
子类 NSLayoutManager 并覆盖 setGlyphs 以显示空格字符:
Subclass NSLayoutManager and override setGlyphs to show space chars:
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 子类.子类将显示换行符并确保每个不可见的字符都用不同的颜色绘制:
Subclass NSATSTypesetter and assign it to your NSLayoutManager subclas. The subclass will display the new line characters and make sure that every invisible character will be drawn with a different color:
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/隐藏不可见字符，只需调用:
To show/hide invisible characters just call:
let storageRange = NSRange(location: 0, length: currentTextStorage.length)
layoutManager.invalidateGlyphs(forCharacterRange: storageRange, changeInLength: 0, actualCharacterRange: nil)
layoutManager.ensureGlyphs(forGlyphRange: storageRange)
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