More efficient solution to line truncation in DTAttributedLabel.

Bug fixes in DTCoreTextLayoutFrame : - paragraphRanges was not properly calculated when a string isn't ended with '\n' - uninitialized variable baseWritingDirection in [DTCoreTextLayoutFrame_buildLinesWithTypesetter] so for a attributed strings without paragraph style (by ex. created with [NSAttributedString initWithString:] ) lines were rendered wrong
RoelandW · Apr 18, 2013 · 5144588 · 5144588
1 parent 732502a
commit 5144588
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Showing 4 changed files with 66 additions and 34 deletions.
diff --git a/Core/Source/DTAttributedLabel.m b/Core/Source/DTAttributedLabel.m
@@ -18,17 +18,6 @@ + (Class)layerClass
 	return [CALayer class];
 }
 
-- (DTCoreTextLayoutFrame *)layoutFrame
-{
-    self.layoutFrameHeightIsConstrainedByBounds = YES; // height is not flexible
-	DTCoreTextLayoutFrame * layoutFrame = [super layoutFrame];
-    layoutFrame.numberOfLines = self.numberOfLines;
-    layoutFrame.lineBreakMode = self.lineBreakMode;
-    layoutFrame.truncationString = self.truncationString;
-	layoutFrame.noLeadingOnFirstLine = YES;
-	return layoutFrame;
-}
-
 - (id)initWithFrame:(CGRect)frame
 {
 	self = [super initWithFrame:frame];
@@ -37,6 +26,9 @@ - (id)initWithFrame:(CGRect)frame
 	{
 		// we want to relayout the text if height or width change
 		self.relayoutMask = DTAttributedTextContentViewRelayoutOnHeightChanged | DTAttributedTextContentViewRelayoutOnWidthChanged;
+
+		self.layoutFrameHeightIsConstrainedByBounds = YES; // height is not flexible
+		self.shouldAddFirstLineLeading = NO;
 	}
 
 	return self;
@@ -57,6 +49,11 @@ - (CGSize)intrinsicContentSize
 
 #pragma mark - Properties 
 
+- (NSInteger)numberOfLines
+{
+	return _numberOfLines;
+}
+
 - (void)setNumberOfLines:(NSInteger)numberOfLines
 {
     if (numberOfLines != _numberOfLines)
@@ -66,6 +63,11 @@ - (void)setNumberOfLines:(NSInteger)numberOfLines
     }
 }
 
+- (NSLineBreakMode)lineBreakMode
+{
+	return _lineBreakMode;
+}
+
 - (void)setLineBreakMode:(NSLineBreakMode)lineBreakMode
 {
     if (lineBreakMode != _lineBreakMode)
@@ -75,17 +77,19 @@ - (void)setLineBreakMode:(NSLineBreakMode)lineBreakMode
     }
 }
 
-- (void)setTruncationString:(NSAttributedString *)trunctionString
+- (NSAttributedString*)truncationString
+{
+	return _truncationString;
+}
+
+- (void)setTruncationString:(NSAttributedString *)truncationString
 {
-    if (trunctionString != _truncationString)
+    if (![truncationString isEqualToAttributedString:_truncationString])
     {
-        _truncationString = trunctionString;
+        _truncationString = truncationString;
         [self relayoutText];
     }
 }
 
-@synthesize numberOfLines = _numberOfLines;
-@synthesize lineBreakMode = _lineBreakMode;
-@synthesize truncationString = _truncationString;
 
 @end
diff --git a/Core/Source/DTAttributedTextContentView.h b/Core/Source/DTAttributedTextContentView.h
@@ -129,6 +129,11 @@ typedef NSUInteger DTAttributedTextContentViewRelayoutMask;
 	NSMutableDictionary *customViewsForAttachmentsIndex;
 
 	BOOL _flexibleHeight;
+
+	// for layoutFrame
+	NSInteger _numberOfLines;
+	NSLineBreakMode _lineBreakMode;
+	NSAttributedString *_truncationString;
 }
 
 

diff --git a/Core/Source/DTAttributedTextContentView.m b/Core/Source/DTAttributedTextContentView.m
@@ -574,6 +574,11 @@ - (CGSize)suggestedFrameSizeToFitEntireStringConstraintedToWidth:(CGFloat)width
 	CGRect rect = [self _frameForLayoutFrameConstraintedToWidth:width];
 	DTCoreTextLayoutFrame *tmpLayoutFrame = [self.layouter layoutFrameWithRect:rect range:NSMakeRange(0, 0)];
 
+	// assign current layout frame properties to tmpLayoutFrame
+	tmpLayoutFrame.numberOfLines = _numberOfLines;
+	tmpLayoutFrame.lineBreakMode = _lineBreakMode;
+	tmpLayoutFrame.truncationString = _truncationString;
+
 	//  we have a layout frame and from this we get the needed size
 	return CGSizeMake(tmpLayoutFrame.frame.size.width + _edgeInsets.left + _edgeInsets.right, CGRectGetMaxY(tmpLayoutFrame.frame) + _edgeInsets.bottom);
 }
@@ -772,6 +777,9 @@ - (DTCoreTextLayoutFrame *)layoutFrame
 
 				_layoutFrame = [theLayouter layoutFrameWithRect:rect range:NSMakeRange(0, 0)];
 				_layoutFrame.noLeadingOnFirstLine = !_shouldAddFirstLineLeading;
+				_layoutFrame.numberOfLines = _numberOfLines;
+				_layoutFrame.lineBreakMode = _lineBreakMode;
+				_layoutFrame.truncationString = _truncationString;
 
 				// this must have been the initial layout pass
 				CGSize neededSize = CGSizeMake(_layoutFrame.frame.size.width + _edgeInsets.left + _edgeInsets.right, CGRectGetMaxY(_layoutFrame.frame) + _edgeInsets.bottom);

diff --git a/Core/Source/DTCoreTextLayoutFrame.m b/Core/Source/DTCoreTextLayoutFrame.m
@@ -419,6 +419,8 @@ - (void)_buildLinesWithTypesetter
 		if (CTParagraphStyleGetValueForSpecifier(paragraphStyle, kCTParagraphStyleSpecifierBaseWritingDirection, sizeof(baseWritingDirection), &baseWritingDirection))
 		{
 			isRTL = (baseWritingDirection == kCTWritingDirectionRightToLeft);
+		} else {
+			baseWritingDirection = kCTWritingDirectionNatural;
 		}
 
 		switch (textAlignment)
@@ -1698,27 +1700,40 @@ - (NSArray *)paragraphRanges
 	{
 		NSString *plainString = [[self attributedStringFragment] string];
 
+		NSInteger stringLength = [plainString length];
 		NSArray *paragraphs = [plainString componentsSeparatedByString:@"\n"];
-		NSRange range = NSMakeRange(0, 0);
-		NSMutableArray *tmpArray = [NSMutableArray array];
-
-		for (NSString *oneString in paragraphs)
-		{
-			range.length = [oneString length]+1;
+		if( [paragraphs count] == 1 ) {
 
-			NSValue *value = [NSValue valueWithRange:range];
-			[tmpArray addObject:value];
+			_paragraphRanges = [NSArray arrayWithObject:[NSValue valueWithRange:NSMakeRange(0, stringLength)]];
 
-			range.location += range.length;
-		}
+		} else {
 
-		// prevent counting a paragraph after a final newline
-		if ([plainString hasSuffix:@"\n"])
-		{
-			[tmpArray removeLastObject];
+			NSRange range = NSMakeRange(0, 0);
+
+			NSMutableArray *tmpArray = [NSMutableArray array];
+
+			for (NSString *oneString in paragraphs)
+			{
+				range.length = [oneString length];
+				if( NSMaxRange(range) < stringLength ) {
+					// add new line character to range
+					range.location += 1;
+				}
+
+				NSValue *value = [NSValue valueWithRange:range];
+				[tmpArray addObject:value];
+
+				range.location += range.length;
+			}
+
+			// prevent counting a paragraph after a final newline
+			if ([plainString hasSuffix:@"\n"])
+			{
+				[tmpArray removeLastObject];
+			}
+
+			_paragraphRanges = [tmpArray copy];
 		}
-
-		_paragraphRanges = [tmpArray copy];
 	}
 
 	return _paragraphRanges;
@@ -1727,7 +1742,7 @@ - (NSArray *)paragraphRanges
 - (void)setNumberOfLines:(NSInteger)numberOfLines
 {
     if( _numberOfLines != numberOfLines ) {
-        _numberOfLines = numberOfLines;
+		_numberOfLines = numberOfLines;
         // clear lines cache
         _lines = nil;
     }