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POiOS CoreText: CTFrameSetter is making wider lines than the CGPath allows
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  1. POiOS CoreText: CTFrameSetter is making wider lines than the CGPath allows
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    copied!<p>I'm using CoreText to render my text in a <code>CGPath</code> that is typically a rectangle. The width of the path is 230 pixels. But when I'm rendering my text, <code>CTLineGetTypographicBounds</code> returns widths of 292 pixels instead of the maximum 230.</p> <p>It all worked fine until I started to use <code>CTRunDelegateCallbacks</code> delegates. I use it because I render images in-place. The callbacks just return the correct width and height of the messages. I don't see what's wrong. It only happens when I add a lot of smileys to the <code>NSAttributedString</code>. I expect that it sets it correctly acros multiple lines but it doesn't.</p> <pre><code>static void _deallocCallback (void* ref) { [(id)ref release]; } static CGFloat _ascentCallback (void *ref) { UIImage* smiley = [(NSDictionary*)ref objectForKey:@"smiley"]; return smiley.size.height; // returns 16 } static CGFloat _widthCallback (void* ref) { UIImage* smiley = [(NSDictionary*)ref objectForKey:@"smiley"]; return smiley.size.width; // returns 16 } - (void)renderText:(NSString*)text inRect:(CGRect)rect { CGMutablePathRef path = createMyPath(); NSAttributedString* attrString = [self _createAttributedString:text]; // Create the frame setter and it's frame CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attrString); CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, attrString.length), path, NULL); // Get the height of the lines CFArrayRef lines = CTFrameGetLines(frame); CFIndex lineCount = CFArrayGetCount(lines); CGFloat ascent, descent, leading; // Get the origins of each line CGPoint origins[lineCount]; CTFrameGetLineOrigins(frame, CFRangeMake(0, 0), origins); // Loop through every line for (CFIndex i = 0; i &lt; lineCount; i++) { // Get the typographic bounds of this line CTLineRef line = (CTLineRef)CFArrayGetValueAtIndex(lines, i); textWidth = CTLineGetTypographicBounds(line, &amp;ascent, &amp;descent, &amp;leading); // __this returns values wider than rect in path__ } } - (NSAttributedString*)_createAttributedString:(NSString*)inString { // Create our default font attribute NSDictionary* fontAttribute = [NSDictionary dictionaryWithObject:(id)_font forKey:(NSString*)kCTFontAttributeName]; // Create the attributed string NSMutableAttributedString* attributedString = [[NSMutableAttributedString alloc] init]; CTRunDelegateCallbacks callbacks; callbacks.version = kCTRunDelegateVersion1; callbacks.getAscent = _ascentCallback; callbacks.getDescent = NULL; callbacks.getWidth = _widthCallback; callbacks.dealloc = _deallocCallback; UIImage* smiley = getSmiley(@"sad.png"); // Do this multiple times to add a long list of smileys NSDictionary* attributes = [NSDictionary dictionaryWithObjectsAndKeys: smiley, @"smiley", nil]; CTRunDelegateRef delegate = CTRunDelegateCreate(&amp;callbacks, attributes); NSDictionary* attributeDelegate = [NSDictionary dictionaryWithObjectsAndKeys:(id)delegate, (NSString *)kCTRunDelegateAttributeName, smiley, @"smiley", nil]; [attributedString appendAttributedString:[[[NSAttributedString alloc] initWithString:@" " attributes:attributeDelegate] autorelease]]; [attributedString appendAttributedString:[[[NSAttributedString alloc] initWithString:@" blablabla " attributes:fontAttribute] autorelease]]; return attributedString; } </code></pre> <p>Thanks, Nicolas</p>
 

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