HUED-8605 Test & Fix Potential truncation issue in LabelLayout

- Added LabelLayout unit test to verify that size calculation logic considers line break mode while calculating LabelLayout size.
- Added line break mode support in LabelLayout to calculate correct size based on line break mode.

LayoutKitTests/LabelLayoutTests.swift

@@ -11,6 +11,12 @@ import LayoutKit
 
 class LabelLayoutTests: XCTestCase {
 
+    // For the defined `sampleText` and `labelLayoutMaxWidth` combination, `LabelLayout` requires 2 line of
+    // text for char-wrapping and 3 lines for word-wrapping/truncating-tail.
+    // So don't change this combination as the tests are based on these values.
+    private static let sampleText = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean comm"
+    private static let labelLayoutMaxWidth = 305
+
     func testNeedsView() {
         let l = LabelLayout(text: "hi").arrangement().makeViews()
         XCTAssertNotNil(l as? UILabel)
@@ -200,10 +206,75 @@ class LabelLayoutTests: XCTestCase {
         let maxSize = CGSize(width: 17, height: .max)
         XCTAssertEqual(layout.measurement(within: maxSize).size, label.sizeThatFits(maxSize))
     }
+
+    func testSizeCalculationWithWordWrapping() {
+        // Use same line break mode for `LabelLayout` and dummy label and then match LabelLayout's size with dummy label's size calculation.
+        verifyTextSizeCalculation(with: LabelLayoutTests.sampleText, lineBreakMode: .byWordWrapping)
+    }
+
+    func testSizeCalculationWithCharWrapping() {
+        // Use same line break mode for `LabelLayout` and dummy label and then match LabelLayout's size with dummy label's size calculation.
+        verifyTextSizeCalculation(with: LabelLayoutTests.sampleText, lineBreakMode: .byCharWrapping)
+    }
+
+    func testSizeCalculationWithDifferentLineBreakMode() {
+        // Use different line break mode for `LabelLayout` and dummy label.
+        // So in this case, size calculation should not match with dummy label's size calculation.
+        let label = UILabel(text: LabelLayoutTests.sampleText, numberOfLines: 0, lineBreakMode: .byCharWrapping)
+        let layout = LabelLayout(text: LabelLayoutTests.sampleText, config: { label in
+            label.text = LabelLayoutTests.sampleText
+        })
+        let maxSize = CGSize(width: LabelLayoutTests.labelLayoutMaxWidth, height: .max)
+        XCTAssertNotEqual(layout.measurement(within: maxSize).size, label.sizeThatFits(maxSize))
+    }
+
+    func testAttributedTextSizeCalculationWithWordWrapping() {
+        // Use same line break mode for `LabelLayout` and dummy label and then match LabelLayout's size with dummy label's size calculation.
+        let attributedText = NSAttributedString(string: LabelLayoutTests.sampleText)
+        verifyAttributedTextSizeCalculation(with: attributedText, lineBreakMode: .byWordWrapping)
+    }
+
+    func testAttributedTextSizeCalculationWithCharWrapping() {
+        // Use same line break mode for `LabelLayout` and dummy label and then match LabelLayout's size with dummy label's size calculation.
+        let attributedText = NSAttributedString(string: LabelLayoutTests.sampleText)
+        verifyAttributedTextSizeCalculation(with: attributedText, lineBreakMode: .byCharWrapping)
+    }
+
+    func testAttributedTextSizeCalculationWithDifferentLineBreakMode() {
+        // Use different line break mode for `LabelLayout` and dummy label.
+        // So in this case, size calculation should not match with dummy label's size calculation.
+        let attributedText = NSAttributedString(string: LabelLayoutTests.sampleText)
+        let label = UILabel(attributedText: attributedText, numberOfLines: 0, lineBreakMode: .byCharWrapping)
+        let layout = LabelLayout(attributedText: attributedText, config: { label in
+            label.attributedText = attributedText
+        })
+        let maxSize = CGSize(width: LabelLayoutTests.labelLayoutMaxWidth, height: .max)
+        XCTAssertNotEqual(layout.measurement(within: maxSize).size, label.sizeThatFits(maxSize))
+    }
+
+    // MARK: Private Helpers
+
+    private func verifyTextSizeCalculation(with text: String, lineBreakMode: NSLineBreakMode) {
+        let label = UILabel(text: text, numberOfLines: 0, lineBreakMode: lineBreakMode)
+        let layout = LabelLayout(text: text, lineBreakMode: lineBreakMode, config: { label in
+            label.text = text
+        })
+        let maxSize = CGSize(width: LabelLayoutTests.labelLayoutMaxWidth, height: .max)
+        XCTAssertEqual(layout.measurement(within: maxSize).size, label.sizeThatFits(maxSize))
+    }
+
+    private func verifyAttributedTextSizeCalculation(with attributedText: NSAttributedString, lineBreakMode: NSLineBreakMode) {
+        let label = UILabel(attributedText: attributedText, numberOfLines: 0, lineBreakMode: lineBreakMode)
+        let layout = LabelLayout(attributedText: attributedText, lineBreakMode: lineBreakMode, config: { label in
+            label.attributedText = attributedText
+        })
+        let maxSize = CGSize(width: LabelLayoutTests.labelLayoutMaxWidth, height: .max)
+        XCTAssertEqual(layout.measurement(within: maxSize).size, label.sizeThatFits(maxSize))
+    }
 }
 
 extension UILabel {
-    convenience init(text: String, font: UIFont? = nil, numberOfLines: Int? = nil) {
+    convenience init(text: String, font: UIFont? = nil, numberOfLines: Int? = nil, lineBreakMode: NSLineBreakMode? = nil) {
         self.init()
         self.text = text
         if let font = font {
@@ -212,16 +283,23 @@ extension UILabel {
         if let numberOfLines = numberOfLines {
             self.numberOfLines = numberOfLines
         }
+        if let lineBreakMode = lineBreakMode {
+            self.lineBreakMode = lineBreakMode
+        }
     }
 
-    convenience init(attributedText: NSAttributedString, font: UIFont? = nil, numberOfLines: Int? = nil) {
+    convenience init(attributedText: NSAttributedString, font: UIFont? = nil, numberOfLines: Int? = nil, lineBreakMode: NSLineBreakMode? = nil) {
         self.init()
         if let font = font {
             self.font = font
         }
         if let numberOfLines = numberOfLines {
             self.numberOfLines = numberOfLines
         }
+        if let lineBreakMode = lineBreakMode {
+            self.lineBreakMode = lineBreakMode
+        }
+
         // Want to set attributed text AFTER font it set, otherwise the font seems to take precedence.
         self.attributedText = attributedText
     }

Sources/Internal/NSAttributedStringExtension.swift

@@ -12,16 +12,18 @@ extension NSAttributedString {
 
     /// Returns a new NSAttributedString with a given font and the same attributes.
     func with(font: UIFont) -> NSAttributedString {
-        let fontAttribute = [NSAttributedStringKey.font: font]
-        let attributedTextWithFont = NSMutableAttributedString(string: string, attributes: fontAttribute)
+        return with(additionalAttributes: [NSAttributedStringKey.font: font])
+    }
+
+    /// Returns a new NSAttributedString with previous as well as additional attributes.
+    func with(additionalAttributes: [NSAttributedStringKey : Any]?) -> NSAttributedString {
+        let attributedTextWithAdditionalAttributes = NSMutableAttributedString(string: string, attributes: additionalAttributes)
         let fullRange = NSMakeRange(0, (string as NSString).length)
-        attributedTextWithFont.beginEditing()
+        attributedTextWithAdditionalAttributes.beginEditing()
         self.enumerateAttributes(in: fullRange, options: .longestEffectiveRangeNotRequired, using: { (attributes, range, _) in
-            attributedTextWithFont.addAttributes(attributes, range: range)
+            attributedTextWithAdditionalAttributes.addAttributes(attributes, range: range)
         })
-        attributedTextWithFont.endEditing()
-
-        return attributedTextWithFont
+        attributedTextWithAdditionalAttributes.endEditing()
+        return attributedTextWithAdditionalAttributes
     }
-
 }

Sources/Layouts/LabelLayout.swift

@@ -17,11 +17,13 @@ open class LabelLayout<Label: UILabel>: BaseLayout<Label>, ConfigurableLayout {
     open let font: UIFont
     open let numberOfLines: Int
     open let lineHeight: CGFloat
+    open let lineBreakMode: NSLineBreakMode
 
     public init(text: Text,
                 font: UIFont = LabelLayoutDefaults.defaultFont,
                 lineHeight: CGFloat? = nil,
                 numberOfLines: Int = LabelLayoutDefaults.defaultNumberOfLines,
+                lineBreakMode: NSLineBreakMode = LabelLayoutDefaults.defaultLineBreakMode,
                 alignment: Alignment = LabelLayoutDefaults.defaultAlignment,
                 flexibility: Flexibility = LabelLayoutDefaults.defaultFlexibility,
                 viewReuseId: String? = nil,
@@ -31,13 +33,15 @@ open class LabelLayout<Label: UILabel>: BaseLayout<Label>, ConfigurableLayout {
         self.numberOfLines = numberOfLines
         self.font = font
         self.lineHeight = lineHeight ?? font.lineHeight
+        self.lineBreakMode = lineBreakMode
         super.init(alignment: alignment, flexibility: flexibility, viewReuseId: viewReuseId, config: config)
     }
 
     init(attributedString: NSAttributedString,
          font: UIFont = LabelLayoutDefaults.defaultFont,
          lineHeight: CGFloat? = nil,
          numberOfLines: Int = LabelLayoutDefaults.defaultNumberOfLines,
+         lineBreakMode: NSLineBreakMode = LabelLayoutDefaults.defaultLineBreakMode,
          alignment: Alignment = LabelLayoutDefaults.defaultAlignment,
          flexibility: Flexibility = LabelLayoutDefaults.defaultFlexibility,
          viewReuseId: String? = nil,
@@ -48,13 +52,15 @@ open class LabelLayout<Label: UILabel>: BaseLayout<Label>, ConfigurableLayout {
         self.numberOfLines = numberOfLines
         self.font = font
         self.lineHeight = lineHeight ?? font.lineHeight
+        self.lineBreakMode = lineBreakMode
         super.init(alignment: alignment, flexibility: flexibility, viewReuseId: viewReuseId, viewClass: viewClass ?? Label.self, config: config)
     }
 
     init(string: String,
          font: UIFont = LabelLayoutDefaults.defaultFont,
          lineHeight: CGFloat? = nil,
          numberOfLines: Int = LabelLayoutDefaults.defaultNumberOfLines,
+         lineBreakMode: NSLineBreakMode = LabelLayoutDefaults.defaultLineBreakMode,
          alignment: Alignment = LabelLayoutDefaults.defaultAlignment,
          flexibility: Flexibility = LabelLayoutDefaults.defaultFlexibility,
          viewReuseId: String? = nil,
@@ -65,6 +71,7 @@ open class LabelLayout<Label: UILabel>: BaseLayout<Label>, ConfigurableLayout {
         self.numberOfLines = numberOfLines
         self.font = font
         self.lineHeight = lineHeight ?? font.lineHeight
+        self.lineBreakMode = lineBreakMode
         super.init(alignment: alignment, flexibility: flexibility, viewReuseId: viewReuseId, viewClass: viewClass ?? Label.self, config: config)
     }
 
@@ -74,6 +81,7 @@ open class LabelLayout<Label: UILabel>: BaseLayout<Label>, ConfigurableLayout {
                             font: UIFont = LabelLayoutDefaults.defaultFont,
                             lineHeight: CGFloat? = nil,
                             numberOfLines: Int = LabelLayoutDefaults.defaultNumberOfLines,
+                            lineBreakMode: NSLineBreakMode = LabelLayoutDefaults.defaultLineBreakMode,
                             alignment: Alignment = LabelLayoutDefaults.defaultAlignment,
                             flexibility: Flexibility = LabelLayoutDefaults.defaultFlexibility,
                             viewReuseId: String? = nil,
@@ -83,6 +91,7 @@ open class LabelLayout<Label: UILabel>: BaseLayout<Label>, ConfigurableLayout {
                   font: font,
                   lineHeight: lineHeight,
                   numberOfLines: numberOfLines,
+                  lineBreakMode: lineBreakMode,
                   alignment: alignment,
                   flexibility: flexibility,
                   viewReuseId: viewReuseId,
@@ -93,6 +102,7 @@ open class LabelLayout<Label: UILabel>: BaseLayout<Label>, ConfigurableLayout {
                             font: UIFont = LabelLayoutDefaults.defaultFont,
                             lineHeight: CGFloat? = nil,
                             numberOfLines: Int = LabelLayoutDefaults.defaultNumberOfLines,
+                            lineBreakMode: NSLineBreakMode = LabelLayoutDefaults.defaultLineBreakMode,
                             alignment: Alignment = LabelLayoutDefaults.defaultAlignment,
                             flexibility: Flexibility = LabelLayoutDefaults.defaultFlexibility,
                             viewReuseId: String? = nil,
@@ -102,6 +112,7 @@ open class LabelLayout<Label: UILabel>: BaseLayout<Label>, ConfigurableLayout {
                   font: font,
                   lineHeight: lineHeight,
                   numberOfLines: numberOfLines,
+                  lineBreakMode: lineBreakMode,
                   alignment: alignment,
                   flexibility: flexibility,
                   viewReuseId: viewReuseId,
@@ -116,7 +127,7 @@ open class LabelLayout<Label: UILabel>: BaseLayout<Label>, ConfigurableLayout {
     }
 
     private func textSize(within maxSize: CGSize) -> CGSize {
-        var size = text.textSize(within: maxSize, font: font)
+        var size = text.textSize(within: maxSize, font: font, lineBreakMode: lineBreakMode)
         if numberOfLines > 0 {
             let maxHeight = (CGFloat(numberOfLines) * lineHeight).roundedUpToFractionalPoint
             if size.height > maxHeight {
@@ -134,6 +145,7 @@ open class LabelLayout<Label: UILabel>: BaseLayout<Label>, ConfigurableLayout {
     open override func configure(view label: Label) {
         config?(label)
         label.numberOfLines = numberOfLines
+        label.lineBreakMode = lineBreakMode
         label.font = font
         switch text {
         case .unattributed(let text):
@@ -155,6 +167,7 @@ public class LabelLayoutDefaults {
     public static let defaultNumberOfLines = 0
     public static let defaultFont = UILabel().font ?? UIFont.systemFont(ofSize: 17)
     public static let defaultAlignment = Alignment.topLeading
+    public static let defaultLineBreakMode = NSLineBreakMode.byTruncatingTail
     public static let defaultFlexibility = Flexibility.flexible
 }
 

Sources/ObjCSupport/Builders/LOKLabelLayoutBuilder.h

@@ -22,6 +22,7 @@
 
 @property (nonatomic, nonnull, readonly) LOKLabelLayoutBuilder * _Nonnull(^font)(UIFont * _Nullable);
 @property (nonatomic, nonnull, readonly) LOKLabelLayoutBuilder * _Nonnull(^numberOfLines)(NSInteger);
+@property (nonatomic, nonnull, readonly) LOKLabelLayoutBuilder * _Nonnull(^lineBreakMode)(NSLineBreakMode);
 @property (nonatomic, nonnull, readonly) LOKLabelLayoutBuilder * _Nonnull(^lineHeight)(CGFloat);
 
 @property (nonatomic, nonnull, readonly) LOKLabelLayoutBuilder * _Nonnull(^alignment)(LOKAlignment * _Nullable);

Sources/ObjCSupport/Builders/LOKLabelLayoutBuilder.m

@@ -21,6 +21,7 @@ @interface LOKLabelLayoutBuilder ()
 @property (nonatomic, nullable) NSAttributedString *privateAttributedString;
 @property (nonatomic, nullable) UIFont *privateFont;
 @property (nonatomic) NSInteger privateNumberOfLines;
+@property (nonatomic) NSLineBreakMode privateLineBreakMode;
 @property (nonatomic) CGFloat privateLineHeight;
 @property (nonatomic, nullable) void (^ privateConfigure)(UILabel * _Nonnull);
 
@@ -87,6 +88,13 @@ - (nonnull LOKLabelLayout *)layout {
     };
 }
 
+- (LOKLabelLayoutBuilder * _Nonnull (^)(NSLineBreakMode))lineBreakMode {
+    return ^LOKLabelLayoutBuilder *(NSLineBreakMode lineBreakMode){
+        self.privateLineBreakMode = lineBreakMode;
+        return self;
+    };
+}
+
 - (LOKLabelLayoutBuilder * _Nonnull (^)(CGFloat))lineHeight {
     return ^LOKLabelLayoutBuilder *(CGFloat lineHeight){
         self.privateLineHeight = lineHeight;

Sources/ObjCSupport/LOKLabelLayout.swift

@@ -13,11 +13,13 @@ import UIKit
     @objc public let string: String?
     @objc public let lineHeight: CGFloat
     @objc public let font: UIFont
+    @objc public let lineBreakMode: NSLineBreakMode?
     @objc public let numberOfLines: Int
     @objc public let alignment: LOKAlignment
     @objc public let viewClass: UILabel.Type
     @objc public let configure: ((UILabel) -> Void)?
 
+    // TODO: Remove this init once all consumers are switch to `init(attributedString:font:lineBreakMode:lineHeight:numberOfLines:alignment:flexibility:viewReuseId:viewClass:configure:)`
     @objc public init(attributedString: NSAttributedString,
                       font: UIFont?,
                       lineHeight: CGFloat,
@@ -29,6 +31,7 @@ import UIKit
                       configure: ((UILabel) -> Void)?) {
         self.attributedString = attributedString
         self.font = font ?? UIFont.systemFont(ofSize: UIFont.systemFontSize)
+        self.lineBreakMode = nil
         self.lineHeight = lineHeight
         self.numberOfLines = numberOfLines
         self.alignment = alignment ?? .topLeading
@@ -49,6 +52,7 @@ import UIKit
         super.init(layout: layout)
     }
 
+    // TODO: Remove this init once all consumers are switch to `init(string:font:lineBreakMode:lineHeight:numberOfLines:alignment:flexibility:viewReuseId:viewClass:configure:)`
     @objc public init(string: String,
                       font: UIFont?,
                       lineHeight: CGFloat,
@@ -60,6 +64,7 @@ import UIKit
                       configure: ((UILabel) -> Void)?) {
         self.string = string
         self.font = font ?? UIFont.systemFont(ofSize: UIFont.systemFontSize)
+        self.lineBreakMode = nil
         self.lineHeight = lineHeight
         self.numberOfLines = numberOfLines
         self.alignment = alignment ?? .topLeading
@@ -78,4 +83,71 @@ import UIKit
             config: self.configure)
         super.init(layout: layout)
     }
+
+    @objc public init(attributedString: NSAttributedString,
+                      font: UIFont?,
+                      lineBreakMode: NSlineBreakMode?,
+                      lineHeight: CGFloat,
+                      numberOfLines: Int,
+                      alignment: LOKAlignment?,
+                      flexibility: LOKFlexibility?,
+                      viewReuseId: String?,
+                      viewClass: UILabel.Type?,
+                      configure: ((UILabel) -> Void)?) {
+        self.attributedString = attributedString
+        self.font = font ?? UIFont.systemFont(ofSize: UIFont.systemFontSize)
+        self.lineBreakMode = lineBreakMode
+        self.lineHeight = lineHeight
+        self.numberOfLines = numberOfLines
+        self.alignment = alignment ?? .topLeading
+        self.viewClass = viewClass ?? UILabel.self
+        self.configure = configure
+        string = nil
+        let layout = LabelLayout<UILabel>(
+            attributedString: attributedString,
+            font: self.font,
+            lineHeight: lineHeight > 0 && lineHeight.isFinite ? lineHeight : Optional<CGFloat>.none,
+            numberOfLines: self.numberOfLines,
+            lineBreakMode: self.lineBreakMode ?? .byTruncatingTail,
+            alignment: self.alignment.alignment,
+            flexibility: flexibility?.flexibility ?? .flexible,
+            viewReuseId: viewReuseId,
+            viewClass: self.viewClass,
+            config: self.configure)
+
+        super.init(layout: layout)
+    }
+
+    @objc public init(string: String,
+                      font: UIFont?,
+                      lineBreakMode: NSlineBreakMode?,
+                      lineHeight: CGFloat,
+                      numberOfLines: Int,
+                      alignment: LOKAlignment?,
+                      flexibility: LOKFlexibility?,
+                      viewReuseId: String?,
+                      viewClass: UILabel.Type?,
+                      configure: ((UILabel) -> Void)?) {
+        self.string = string
+        self.font = font ?? UIFont.systemFont(ofSize: UIFont.systemFontSize)
+        self.lineBreakMode = lineBreakMode
+        self.lineHeight = lineHeight
+        self.numberOfLines = numberOfLines
+        self.alignment = alignment ?? .topLeading
+        self.viewClass = viewClass ?? UILabel.self
+        self.configure = configure
+        attributedString = nil
+        let layout = LabelLayout<UILabel>(
+            string: string,
+            font: self.font,
+            lineHeight: lineHeight > 0 && lineHeight.isFinite ? lineHeight : Optional<CGFloat>.none,
+            numberOfLines: self.numberOfLines,
+            lineBreakMode: self.lineBreakMode ?? .byTruncatingTail,
+            alignment: self.alignment.alignment,
+            flexibility: flexibility?.flexibility ?? .flexible,
+            viewReuseId: viewReuseId,
+            viewClass: self.viewClass,
+            config: self.configure)
+        super.init(layout: layout)
+    }
 }