The complete implementation of my answer to a StackOverflow question about how to hit test the actual text of a UILabel. http://stackoverflow.com/a/17379627/608157

TextHitTestingLabel.m

//
//  TextHitTestingLabel.m
//  rotate
//
//  Created by David Rönnqvist on 2013-06-29.
//

#import "TextHitTestingLabel.h"
#import <CoreText/CoreText.h>

@interface TextHitTestingLabel (/*Private stuff*/)
@property (assign) CGPathRef textPath;
@end

@implementation TextHitTestingLabel

// Override -pointInside:withEvent to determine that ourselves.
- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
	// Check if the points is inside the text path.
	return CGPathContainsPoint(self.textPath, NULL, point, NO);
}

- (void)setText:(NSString *)text {
	[super setText:text];
	
	[self textChanged];
}

- (void)setAttributedText:(NSAttributedString *)attributedText {
	[super setAttributedText:attributedText];
	
	[self textChanged];
}

- (void)awakeFromNib {
	[self textChanged];
}

- (void)textChanged
{
	// Get the text
	NSAttributedString *attributedString = nil;
	if ([self respondsToSelector:@selector(attributedText)]) { // Available in iOS 6
		attributedString = self.attributedText;
	}
	if (!attributedString) { // Either earlier than iOS6 or the `text` property was set instead of `attributedText`
		attributedString = [[NSAttributedString alloc] initWithString:self.text
														   attributes:@{NSFontAttributeName: self.font}];
	}
	
	// Create a mutable path for the paths of all the letters.
	CGMutablePathRef letters = CGPathCreateMutable();
	
	// Some CoreText "magic"
	//
	// Core Text works with lines of text. Glyphs are representing letters on screen.
	// Consecutive letters with the same font and style are grouped in a glyph run.
	// (see moe comments below)
	
	// Create a line from the attributed string and get glyph runs from that line
	CTLineRef line = CTLineCreateWithAttributedString((CFAttributedStringRef)attributedString);
	CFArrayRef runArray = CTLineGetGlyphRuns(line);
	
	// A line with more then one font, style, size etc will have multiple fonts.
	// "Hello" formatted as " *Hel* lo " (spaces added for clarity) is two glyph
	// runs: one italics and one regular. The first run contains 3 glyphs and the
	// second run contains 2 glyphs.
	// Note that " He *ll* o " is 3 runs even though "He" and "o" have the same font.
	for (CFIndex runIndex = 0; runIndex < CFArrayGetCount(runArray); runIndex++)
	{
		// Get the font for this glyph run.
		CTRunRef run = (CTRunRef)CFArrayGetValueAtIndex(runArray, runIndex);
		CTFontRef runFont = CFDictionaryGetValue(CTRunGetAttributes(run), kCTFontAttributeName);
		
		// This glyph run contains one or more glyphs (letters etc.)
		for (CFIndex runGlyphIndex = 0; runGlyphIndex < CTRunGetGlyphCount(run); runGlyphIndex++)
		{
			// Read the glyph itself and it position from the glyph run.
			CFRange glyphRange = CFRangeMake(runGlyphIndex, 1);
			CGGlyph glyph;
			CGPoint position;
			CTRunGetGlyphs(run, glyphRange, &glyph);
			CTRunGetPositions(run, glyphRange, &position);
			
			// Create a CGPath for the outline of the glyph
			CGPathRef letter = CTFontCreatePathForGlyph(runFont, glyph, NULL);
			// Translate it to its position.
			CGAffineTransform t = CGAffineTransformMakeTranslation(position.x, position.y);
			// Add the glyph to the
			CGPathAddPath(letters, &t, letter);
			CGPathRelease(letter);
		}
	}
	CFRelease(line);
	
	
	// Transform the path to not be upside down
	CGAffineTransform t = CGAffineTransformMakeScale(1, -1); // flip 1
	CGSize pathSize = CGPathGetBoundingBox(letters).size;
	t = CGAffineTransformTranslate(t, 0, -pathSize.height); // move down
	
	// Create the final path by applying the transform
//	CGPathRef finalPath = CGPathCreateMutableCopyByTransformingPath(letters, &t);
	
	CGPathRef endPath = CGPathCreateMutableCopyByTransformingPath(letters, &t);
	
	CGMutablePathRef finalPath = CGPathCreateMutableCopy(endPath);
	CGPathRef strokedPath = CGPathCreateCopyByStrokingPath(endPath, NULL, 7, kCGLineCapRound, kCGLineJoinRound, 0);
	CGPathAddPath(finalPath, NULL, strokedPath);
	
	// Clean up all the unused paths
	CGPathRelease(strokedPath);
	CGPathRelease(letters);
	CGPathRelease(endPath);
	
	self.textPath = finalPath;
}

@end