UIFont+CharacterWidth.m

// UIFont+CharacterWidth.m

- (CGFloat)characterWidth
{
	CGFloat characterWidth = 0.0;

	// get the width of a character by doing a layout with two spaces and measuring the position of the second glyph
	NSAttributedString *measureAttributedString = [[NSAttributedString alloc] initWithString:@"  " attributes:@{ NSFontAttributeName: self }];
	CTLineRef lineRef = CTLineCreateWithAttributedString((CFAttributedStringRef)measureAttributedString);
	CFArrayRef arrayRef = CTLineGetGlyphRuns(lineRef);
	CTRunRef runRef = CFArrayGetValueAtIndex(arrayRef, 0);
	CGPoint *positions = (CGPoint *)CTRunGetPositionsPtr(runRef);
	
	CFIndex count = CTRunGetGlyphCount(runRef);
	if (count == 2) {
		characterWidth = positions[1].x;
	}
		
	CFRelease(lineRef);
	
	return characterWidth;
}