How to change an UILabel/UIFont's letter spacing?

From iOS 6 you can use NSAttributedString in UILabel.

In attributed string you can use attribute NSKernAttributeName to set letter spacing

NSMutableAttributedString* attrStr = [[NSMutableAttributedString alloc] initWithString: @"Test test test test "];[attrStr addAttribute:NSKernAttributeName value:@(4.0) range:NSMakeRange(0, attrStr.length)];UILabel* label = [[UILabel alloc] initWithFrame:CGRectMake(0, 300, 300, 100)];label.attributedText = attrStr;

I've extended UILabel to change the character spacing. This should work out the box and pulls font, text, color etc from the UILabel itself (proper coding!).

You may notice I draw the text twice, first with clear color. This is to auto center the text in the label. Whilst this may be inefficient - isn't it nice to be auto centered?

Enjoy!

@interface RALabel : UILabel {}@end  @implementation RALabel - (void) drawRect:(CGRect)rect {    // Drawing code    CGContextRef context = UIGraphicsGetCurrentContext();    CGContextSelectFont (context, [self.font.fontName cStringUsingEncoding:NSASCIIStringEncoding], self.font.pointSize, kCGEncodingMacRoman);    CGContextSetCharacterSpacing(context, 1);    CGContextSetFillColorWithColor(context, [[UIColor clearColor] CGColor]);    CGAffineTransform myTextTransform = CGAffineTransformScale(CGAffineTransformIdentity, 1.f, -1.f );    CGContextSetTextMatrix (context, myTextTransform);    // draw 1 but invisbly to get the string length.    CGPoint p =CGContextGetTextPosition(context);    float centeredY = (self.font.pointSize + (self.frame.size.height- self.font.pointSize)/2)-2;    CGContextShowTextAtPoint(context, 0, centeredY, [self.text cStringUsingEncoding:NSASCIIStringEncoding], [self.text length]);    CGPoint v =CGContextGetTextPosition(context);    // calculate width and draw second one.    float width = v.x - p.x;    float centeredX =(self.frame.size.width- width)/2;    CGContextSetFillColorWithColor(context, [self.textColor CGColor]);    CGContextShowTextAtPoint(context, centeredX, centeredY, [self.text cStringUsingEncoding:NSASCIIStringEncoding], [self.text length]);}

I've come up with a solution for the letter spacing and the alignment to the right.

Here it goes:

    NSString *number = [NSString stringWithFormat:@"%d", total];    int lastPos = 85;    NSUInteger i;    for (i = number.length; i > 0; i--)    {        NSRange range = {i-1,1};        NSString *n = [number substringWithRange:range];        UILabel *digit = [[[UILabel alloc] initWithFrame:CGRectMake(5, 10, 35, 50)] autorelease];        digit.text = n;        digit.font = [UIFont fontWithName:@"Arial-BoldMT" size:60];        digit.textColor = [UIColor colorWithRed:221/255.0 green:221/255.0 blue:221/255.0 alpha:1.0];        digit.backgroundColor = [UIColor clearColor];        [self addSubview:digit];        CGSize textSize = [[digit text] sizeWithFont:[digit font]];        CGFloat textWidth = textSize.width;        CGRect rect = digit.frame;        rect.origin.x = lastPos - textWidth;        digit.frame = rect;        lastPos = rect.origin.x + 10;    }

The letter spacing is the "10" on the last line.The alignment comes from the lastPos.

Hope this helps anyone out there.