HUED-8605 Test & Fix Potential truncation issue in LabelLayout

- Added line break mode support in LabelLayout to calculate correct size based on line break mode.

Author: PrkumariLI

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)
+    }
 }

Sources/Text.swift

@@ -13,33 +13,47 @@ public enum Text {
     case unattributed(String)
     case attributed(NSAttributedString)
 
-    /// Calculate the text size within `maxSize` by given `UIFont`
+    /// Calculate the text size within `maxSize` by given `UIFont` and `NSLineBreakMode`
     func textSize(within maxSize: CGSize,
-                  font: UIFont) -> CGSize {
+                  font: UIFont,
+                  lineBreakMode: NSLineBreakMode = .byTruncatingTail) -> CGSize {
         let options: NSStringDrawingOptions = [
             .usesLineFragmentOrigin
         ]
 
+        /**
+         By default `boundingRect(with:options:attributes:)` seems to be using `lineBreakMode=byWordWrapping` to calculate size,
+         so if UILabel/UITextView's mode is char wrapping, we get more height than required.
+         So use `paragraphStyle` only in case when UILabel/UITextView's mode is `byCharWrapping` because if we use `paragraphStyle`
+         with `byTruncatingTail`, `boundingRect(with:options:attributes:)` always give single line height.
+         */
+        var attributes: [NSAttributedStringKey: Any] = [NSAttributedStringKey.font: font]
+        if lineBreakMode == .byCharWrapping {
+            let paragraphStyle = NSMutableParagraphStyle()
+            paragraphStyle.lineBreakMode = lineBreakMode
+            attributes[NSAttributedStringKey.paragraphStyle] = paragraphStyle
+        }
+
         let size: CGSize
         switch self {
         case .attributed(let attributedText):
             if attributedText.length == 0 {
                 return .zero
             }
 
-            // UILabel/UITextView uses a default font if one is not specified in the attributed string.
+            // UILabel/UITextView uses a default font and lineBreakMode if one is not specified in the attributed string.
             // boundingRect(with:options:attributes:) does not appear to have the same logic,
-            // so we need to ensure that our attributed string has a default font.
-            // We do this by creating a new attributed string with the default font and then
+            // so we need to ensure that our attributed string has a default font and lineBreakMode.
+            // We do this by creating a new attributed string with the default font & lineBreakMode and then
             // applying all of the attributes from the provided attributed string.
-            let fontAppliedAttributeString = attributedText.with(font: font)
+            let newAttributedString = attributedText.with(additionalAttributes: attributes)
 
-            size = fontAppliedAttributeString.boundingRect(with: maxSize, options: options, context: nil).size
+            size = newAttributedString.boundingRect(with: maxSize, options: options, context: nil).size
         case .unattributed(let text):
             if text.isEmpty {
                 return .zero
             }
-            size = text.boundingRect(with: maxSize, options: options, attributes: [NSAttributedStringKey.font: font], context: nil).size
+            size = text.boundingRect(with: maxSize, options: options, attributes: attributes, context: nil).size
         }
         // boundingRect(with:options:attributes:) returns size to a precision of hundredths of a point,
         // but UILabel only returns sizes with a point precision of 1/screenDensity.