Fix UILabel TextKit truncation hit testing

Sources/Extension/UIKit/UILabel/UILabelExtension.swift

@@ -266,8 +266,14 @@ fileprivate extension UILabel {
     }
 
     func matching(_ point: CGPoint) -> (NSRange, Action)? {
-        let text = adaptation(scaledAttributedText ?? synthesizedAttributedText ?? attributedText, with: numberOfLines)
+        let text = adaptation(
+            scaledAttributedText ?? synthesizedAttributedText ?? attributedText,
+            with: numberOfLines,
+            lineBreakMode: lineBreakMode,
+            textAlignment: textAlignment
+        )
         guard let attributedString = AttributedString(text) else { return nil }
+        guard attributedString.value.length > 0 else { return nil }
 
         // 构建同步Label的TextKit
         let delegate = UILabelLayoutManagerDelegate(scaledMetrics, with: baselineAdjustment)
@@ -302,6 +308,16 @@ fileprivate extension UILabel {
         // 获取字形下标
         var fraction: CGFloat = 0
         let glyphIndex = layoutManager.glyphIndex(for: point, in: textContainer, fractionOfDistanceThroughGlyph: &fraction)
+        let glyphRange = layoutManager.glyphRange(for: textContainer)
+        guard glyphRange.contains(glyphIndex) else {
+            return nil
+        }
+        // A truncated line can still map a touch to a character that is not
+        // visible. Do not trigger an action for the hidden part of the text.
+        let truncatedGlyphRange = layoutManager.truncatedGlyphRange(inLineFragmentForGlyphAt: glyphIndex)
+        guard truncatedGlyphRange.location == NSNotFound || !truncatedGlyphRange.contains(glyphIndex) else {
+            return nil
+        }
         // 获取字符下标
         let index = layoutManager.characterIndexForGlyph(at: glyphIndex)
         // 通过字形距离判断是否在字形范围内
@@ -431,7 +447,12 @@ extension UILabel {
         return scaledMetrics?.scaledAttributedText
     }
 
-    private func adaptation(_ string: NSAttributedString?, with numberOfLines: Int) -> NSAttributedString? {
+    private func adaptation(
+        _ string: NSAttributedString?,
+        with numberOfLines: Int,
+        lineBreakMode: NSLineBreakMode,
+        textAlignment: NSTextAlignment
+    ) -> NSAttributedString? {
         /**
         由于富文本中的lineBreakMode对于UILabel和TextKit的行为是不一致的, UILabel默认的.byTruncatingTail在TextKit中则无法正确显示.
         所以将富文本中的lineBreakMode全部替换为TextKit默认的.byWordWrapping, 以解决多行显示和不一致的问题.
@@ -442,14 +463,36 @@ extension UILabel {
         }
 
         let mutable = NSMutableAttributedString(attributedString: string)
+        let wrappingMode: NSLineBreakMode
+        if numberOfLines == 1 {
+            wrappingMode = .byCharWrapping
+        } else {
+            switch lineBreakMode {
+            case .byTruncatingHead, .byTruncatingMiddle, .byTruncatingTail:
+                // TextKit performs the final truncation in the text
+                // container. The paragraph itself must remain wrappable.
+                wrappingMode = .byWordWrapping
+            default:
+                wrappingMode = lineBreakMode
+            }
+        }
         mutable.enumerateAttribute(
             .paragraphStyle,
             in: .init(location: 0, length: mutable.length),
             options: .longestEffectiveRangeNotRequired
         ) { (value, range, stop) in
-            guard let old = value as? NSParagraphStyle else { return }
-            guard let new = old.mutableCopy() as? NSMutableParagraphStyle else { return }
-            new.lineBreakMode = numberOfLines == 1 ? .byCharWrapping : .byWordWrapping
+            let new: NSMutableParagraphStyle
+            if let old = value as? NSParagraphStyle,
+               let copy = old.mutableCopy() as? NSMutableParagraphStyle {
+                new = copy
+            } else {
+                new = NSMutableParagraphStyle()
+                new.alignment = textAlignment
+            }
+            if new.alignment == .natural {
+                new.alignment = textAlignment
+            }
+            new.lineBreakMode = wrappingMode
             if #available(iOS 11.0, *) {
                 new.setValue(1, forKey: "lineBreakStrategy")
             }

Sources/Extension/UIKit/UILabel/UILabelLayoutManagerDelegate.swift

@@ -78,7 +78,6 @@ class UILabelLayoutManagerDelegate: NSObject, NSLayoutManagerDelegate {
                 used.size.height = scaledMetrics.scaledSize.height
 
             case .alignCenters:
-                print(scaledMetrics)
                 // 居中的基线偏移 使用Scaled的尺寸高度
                 var baseline = baselineOffset.pointee
                 // 整行的占用高度 - 缩放的行高 = 上下边距; 上边距 = 上下边距 * 0.5; 居中的基线偏移 = 上边距 + 缩放的基线偏移
@@ -111,13 +110,10 @@ class UILabelLayoutManagerDelegate: NSObject, NSLayoutManagerDelegate {
         lineFragmentRect.pointee = rect
         lineFragmentUsedRect.pointee = used
 
-        /**
-        From apple's doc:
-        true if you modified the layout information and want your modifications to be used or false if the original layout information should be used.
-        But actually returning false is also used. : )
-        We should do this to solve the problem of exclusionPaths not working.
-        */
-        return false
+        // The rectangles above are the synchronization layer between UILabel
+        // and TextKit. Returning false tells NSLayoutManager to discard those
+        // changes and use its proposed geometry instead.
+        return true
     }
 
     // Implementing this method with a return value 0 will solve the problem of last line disappearing