[React Native] #WIP Modify RCTShadowText measure function to honor maxNumberOfLines property

Libraries/Text/RCTShadowText.h

@@ -23,7 +23,7 @@ extern NSString *const RCTReactTagAttributeName;
 @property (nonatomic, copy) NSString *fontStyle;
 @property (nonatomic, assign) BOOL isHighlighted;
 @property (nonatomic, assign) CGFloat lineHeight;
-@property (nonatomic, assign) NSInteger maxNumberOfLines;
+@property (nonatomic, assign) NSUInteger maximumNumberOfLines;
 @property (nonatomic, assign) CGSize shadowOffset;
 @property (nonatomic, assign) NSTextAlignment textAlign;
 
@@ -31,6 +31,8 @@ extern NSString *const RCTReactTagAttributeName;
 @property (nonatomic, strong) UIFont *font;
 @property (nonatomic, assign) NSLineBreakMode truncationMode;
 
-- (NSAttributedString *)attributedString;
+@property (nonatomic, copy, readonly) NSAttributedString *attributedString;
+@property (nonatomic, strong, readonly) NSLayoutManager *layoutManager;
+@property (nonatomic, strong, readonly) NSTextContainer *textContainer;
 
 @end

Libraries/Text/RCTShadowText.m

@@ -20,9 +20,17 @@ NSString *const RCTReactTagAttributeName = @"ReactTagAttributeName";
 static css_dim_t RCTMeasure(void *context, float width)
 {
   RCTShadowText *shadowText = (__bridge RCTShadowText *)context;
-  CGSize computedSize = [[shadowText attributedString] boundingRectWithSize:(CGSize){isnan(width) ? CGFLOAT_MAX : width, CGFLOAT_MAX}
-                                                                    options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading
-                                                                    context:nil].size;
+
+  NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:[shadowText attributedString]];
+  [textStorage addLayoutManager:shadowText.layoutManager];
+
+  shadowText.textContainer.size = CGSizeMake(isnan(width) ? CGFLOAT_MAX : width, CGFLOAT_MAX);
+  shadowText.layoutManager.textStorage = textStorage;
+  [shadowText.layoutManager ensureLayoutForTextContainer:shadowText.textContainer];
+
+  CGSize computedSize = [shadowText.layoutManager usedRectForTextContainer:shadowText.textContainer].size;
+
+  [textStorage removeLayoutManager:shadowText.layoutManager];
 
   css_dim_t result;
   result.dimensions[CSS_WIDTH] = RCTCeilPixelValue(computedSize.width);
@@ -30,8 +38,9 @@ static css_dim_t RCTMeasure(void *context, float width)
   return result;
 }
 
-@implementation RCTShadowText
-{
+@implementation RCTShadowText {
+  NSLayoutManager *_layoutManager;
+  NSTextContainer *_textContainer;
   NSAttributedString *_cachedAttributedString;
   UIFont *_font;
 }
@@ -41,7 +50,15 @@ static css_dim_t RCTMeasure(void *context, float width)
   if ((self = [super init])) {
     _fontSize = NAN;
     _isHighlighted = NO;
+
+    _textContainer = [[NSTextContainer alloc] init];
+    _textContainer.lineBreakMode = NSLineBreakByTruncatingTail;
+    _textContainer.lineFragmentPadding = 0.0;
+
+    _layoutManager = [[NSLayoutManager alloc] init];
+    [_layoutManager addTextContainer:_textContainer];
   }
+
   return self;
 }
 
@@ -201,11 +218,31 @@ RCT_TEXT_PROPERTY(FontFamily, _fontFamily, NSString *);
 RCT_TEXT_PROPERTY(FontSize, _fontSize, CGFloat);
 RCT_TEXT_PROPERTY(FontWeight, _fontWeight, NSString *);
 RCT_TEXT_PROPERTY(LineHeight, _lineHeight, CGFloat);
-RCT_TEXT_PROPERTY(MaxNumberOfLines, _maxNumberOfLines, NSInteger);
 RCT_TEXT_PROPERTY(ShadowOffset, _shadowOffset, CGSize);
 RCT_TEXT_PROPERTY(TextAlign, _textAlign, NSTextAlignment);
-RCT_TEXT_PROPERTY(TruncationMode, _truncationMode, NSLineBreakMode);
 RCT_TEXT_PROPERTY(IsHighlighted, _isHighlighted, BOOL);
 RCT_TEXT_PROPERTY(Font, _font, UIFont *);
 
+- (NSLineBreakMode)truncationMode
+{
+  return _textContainer.lineBreakMode;
+}
+
+- (void)setTruncationMode:(NSLineBreakMode)truncationMode
+{
+  _textContainer.lineBreakMode = truncationMode;
+  [self dirtyText];
+}
+
+- (NSUInteger)maximumNumberOfLines
+{
+  return _textContainer.maximumNumberOfLines;
+}
+
+- (void)setMaximumNumberOfLines:(NSUInteger)maximumNumberOfLines
+{
+  _textContainer.maximumNumberOfLines = maximumNumberOfLines;
+  [self dirtyText];
+}
+
 @end

Libraries/Text/RCTText.h

@@ -11,9 +11,10 @@
 
 @interface RCTText : UIView
 
+@property (nonatomic, strong) NSLayoutManager *layoutManager;
+@property (nonatomic, strong) NSTextContainer *textContainer;
 @property (nonatomic, copy) NSAttributedString *attributedText;
-@property (nonatomic, assign) NSLineBreakMode lineBreakMode;
-@property (nonatomic, assign) NSUInteger numberOfLines;
+
 @property (nonatomic, assign) UIEdgeInsets contentInset;
 
 @end

Libraries/Text/RCTText.m

@@ -23,15 +23,7 @@
 - (instancetype)initWithFrame:(CGRect)frame
 {
   if ((self = [super initWithFrame:frame])) {
-    _textContainer = [[NSTextContainer alloc] init];
-    _textContainer.lineBreakMode = NSLineBreakByTruncatingTail;
-    _textContainer.lineFragmentPadding = 0.0;
-
-    _layoutManager = [[NSLayoutManager alloc] init];
-    [_layoutManager addTextContainer:_textContainer];
-
     _textStorage = [[NSTextStorage alloc] init];
-    [_textStorage addLayoutManager:_layoutManager];
 
     self.contentMode = UIViewContentModeRedraw;
   }
@@ -50,25 +42,31 @@
   [self setNeedsDisplay];
 }
 
-- (NSUInteger)numberOfLines
+- (void)setTextContainer:(NSTextContainer *)textContainer
 {
-  return _textContainer.maximumNumberOfLines;
-}
+  if ([_textContainer isEqual:textContainer]) return;
+
+  _textContainer = textContainer;
+
+  for (NSInteger i = _layoutManager.textContainers.count - 1; i >= 0; i--) {
+    [_layoutManager removeTextContainerAtIndex:i];
+  }
+  [_layoutManager addTextContainer:_textContainer];
 
-- (void)setNumberOfLines:(NSUInteger)numberOfLines
-{
-  _textContainer.maximumNumberOfLines = numberOfLines;
   [self setNeedsDisplay];
 }
 
-- (NSLineBreakMode)lineBreakMode
+- (void)setLayoutManager:(NSLayoutManager *)layoutManager
 {
-  return _textContainer.lineBreakMode;
-}
+  if ([_layoutManager isEqual:layoutManager]) return;
+
+  _layoutManager = layoutManager;
+
+  for (NSLayoutManager *layoutManager in _textStorage.layoutManagers) {
+    [_textStorage removeLayoutManager:layoutManager];
+  }
+  [_textStorage addLayoutManager:_layoutManager];
 
-- (void)setLineBreakMode:(NSLineBreakMode)lineBreakMode
-{
-  _textContainer.lineBreakMode = lineBreakMode;
   [self setNeedsDisplay];
 }
 

Libraries/Text/RCTTextManager.m

@@ -33,15 +33,6 @@
 #pragma mark - View properties
 
 RCT_REMAP_VIEW_PROPERTY(containerBackgroundColor, backgroundColor, UIColor)
-RCT_CUSTOM_VIEW_PROPERTY(numberOfLines, NSInteger, RCTText)
-{
-  NSLineBreakMode truncationMode = NSLineBreakByClipping;
-  view.numberOfLines = json ? [RCTConvert NSInteger:json] : defaultView.numberOfLines;
-  if (view.numberOfLines > 0) {
-    truncationMode = NSLineBreakByTruncatingTail;
-  }
-  view.lineBreakMode = truncationMode;
-}
 
 #pragma mark - Shadow properties
 
@@ -65,8 +56,8 @@ RCT_CUSTOM_SHADOW_PROPERTY(containerBackgroundColor, UIColor, RCTShadowText)
 RCT_CUSTOM_SHADOW_PROPERTY(numberOfLines, NSInteger, RCTShadowText)
 {
   NSLineBreakMode truncationMode = NSLineBreakByClipping;
-  view.maxNumberOfLines = json ? [RCTConvert NSInteger:json] : defaultView.maxNumberOfLines;
-  if (view.maxNumberOfLines > 0) {
+  view.maximumNumberOfLines = json ? [RCTConvert NSInteger:json] : defaultView.maximumNumberOfLines;
+  if (view.maximumNumberOfLines > 0) {
     truncationMode = NSLineBreakByTruncatingTail;
   }
   view.truncationMode = truncationMode;
@@ -124,12 +115,16 @@ RCT_CUSTOM_SHADOW_PROPERTY(numberOfLines, NSInteger, RCTShadowText)
   };
 }
 
-- (RCTViewManagerUIBlock)uiBlockToAmendWithShadowView:(RCTShadowView *)shadowView
+- (RCTViewManagerUIBlock)uiBlockToAmendWithShadowView:(RCTShadowText *)shadowView
 {
   NSNumber *reactTag = shadowView.reactTag;
   UIEdgeInsets padding = shadowView.paddingAsInsets;
+
   return ^(RCTUIManager *uiManager, RCTSparseArray *viewRegistry) {
-    ((RCTText *)viewRegistry[reactTag]).contentInset = padding;
+    RCTText *text = (RCTText *)viewRegistry[reactTag];
+    text.contentInset = padding;
+    text.layoutManager = shadowView.layoutManager;
+    text.textContainer = shadowView.textContainer;
   };
 }