优化代码

Author: lixiang1994

Demo/Demo/Debug/DebugLabelView.swift

@@ -96,13 +96,15 @@ class DebugLabelView: UIView {
         didSet {
             let value = lineSpacing
             lineSpacingLabel.text = String(format: "%.2f", value)
+            lineSpacingSlider.value = .init(value)
         }
     }
 
     var lineHeightMultiple: CGFloat = 0 {
         didSet {
             let value = lineHeightMultiple
             lineHeightMultipleLabel.text = String(format: "%.2f", value)
+            lineHeightMultipleSlider.value = .init(value)
         }
     }
 

Demo/Demo/Debug/DebugLabelViewController.swift

@@ -15,6 +15,20 @@ class DebugLabelViewController: ViewController<DebugLabelView> {
 
     private var info: Debug.Label = .init() {
         didSet {
+            if let value = info.lineSpacing {
+                paragraphs.removeAll(where: { $0 == .lineSpacing(0) })
+                paragraphs.append(.lineSpacing(value))
+                
+            } else {
+                paragraphs.removeAll(where: { $0 == .lineSpacing(0) })
+            }
+            if let value = info.lineHeightMultiple {
+                paragraphs.removeAll(where: { $0 == .lineHeightMultiple(0) })
+                paragraphs.append(.lineHeightMultiple(value))
+                
+            } else {
+                paragraphs.removeAll(where: { $0 == .lineHeightMultiple(0) })
+            }
             container.set(info: info)
         }
     }
@@ -108,11 +122,13 @@ class DebugLabelViewController: ViewController<DebugLabelView> {
     }
 
     @IBAction func lineSpacingSliderAction(_ sender: UISlider) {
+        paragraphs.removeAll(where: { $0 == .lineSpacing(0) })
         paragraphs.append(.lineSpacing(.init(sender.value)))
         info.lineSpacing = .init(sender.value)
         update()
     }
     @IBAction func lineHeightMultipleSliderAction(_ sender: UISlider) {
+        paragraphs.removeAll(where: { $0 == .lineHeightMultiple(0) })
         paragraphs.append(.lineHeightMultiple(.init(sender.value)))
         info.lineHeightMultiple = .init(sender.value)
         update()

Sources/Extension/UIKit/UILabel/UILabelLayoutManagerDelegate.swift

@@ -65,12 +65,8 @@ class UILabelLayoutManagerDelegate: NSObject, NSLayoutManagerDelegate {
 
         var rect = lineFragmentRect.pointee
         var used = lineFragmentUsedRect.pointee
-        // 以最大的高度为准 (可解决附件问题), 同时根据最大行数是否为1来判断used是否需要增加行间距, 以解决1行时应该无行间距的问题.
-        let temp = max(maximum.lineHeight, used.height)
-        rect.size.height = temp + maximum.lineSpacing + paragraphSpacing + paragraphSpacingBefore
-        used.size.height = textContainer.maximumNumberOfLines == 1 ? temp : temp + maximum.lineSpacing
 
-        // 当Label发生Scaled时 最大行数为1时 基线偏移不会按比例计算
+        // 当Label发生Scaled时 最大行数为1时
         if let scaledMetrics = scaledMetrics, textContainer.maximumNumberOfLines == 1 {
             switch baselineAdjustment {
             case .alignBaselines:
@@ -103,6 +99,12 @@ class UILabelLayoutManagerDelegate: NSObject, NSLayoutManagerDelegate {
             default:
                 break
             }
+            
+        } else {
+            // 以最大的高度为准 (可解决附件问题), 同时根据最大行数是否为1来判断used是否需要增加行间距, 以解决1行时应该无行间距的问题.
+            let temp = max(maximum.lineHeight, used.height)
+            rect.size.height = temp + maximum.lineSpacing + paragraphSpacing + paragraphSpacingBefore
+            used.size.height = temp
         }
 
         // 重新赋值最终结果

Sources/ParagraphStyle.swift

@@ -156,3 +156,10 @@ extension AttributedString.Attribute.ParagraphStyle {
         return .init(style: [.allowsDefaultTighteningForTruncation: value])
     }
 }
+
+extension AttributedString.Attribute.ParagraphStyle: Equatable {
+    
+    public static func == (lhs: AttributedString.Attribute.ParagraphStyle, rhs: AttributedString.Attribute.ParagraphStyle) -> Bool {
+        return lhs.style.keys == rhs.style.keys
+    }
+}