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

Question

I've searched loads already and couldn't find an answer.
I have a normal UILabel, defined this way:
UILabel *totalColors = [[[UILabel alloc] initWithFrame:CGRectMake(5, 7, 120, 69)] autorelease];
totalColors.text = [NSString stringWithFormat:#"%d", total];
totalColors.font = [UIFont fontWithName:#"Arial-BoldMT" size:60];
totalColors.textColor = [UIColor colorWithRed:221/255.0 green:221/255.0 blue:221/255.0 alpha:1.0];
totalColors.backgroundColor = [UIColor clearColor];
[self addSubview:totalColors];
And I wanted the horizontal spacing between letters, to be tighter, whilst mantaining the font size.
Is there a way to do this? It should be a pretty basic thing to do.
Cheers guys,
Andre
UPDATE:
So I was forced to do it like this:
- (void) drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSelectFont (context, "Arial-BoldMT", 60, kCGEncodingMacRoman);
CGContextSetCharacterSpacing (context, -10);
CGContextSetTextDrawingMode (context, kCGTextFill);
CGContextSetRGBFillColor(context, 221/255.0, 221/255.0, 221/255.0, 221/255.0);
CGAffineTransform xform = CGAffineTransformMake(1.0, 0.0, 0.0, -1.0, 0.0, 0.0);
CGContextSetTextMatrix(context, xform);
char* result = malloc(17);
sprintf(result, "%d", totalNumber);
CGContextShowTextAtPoint (context, 0, 54, result, strlen(result));
}
But I need to align this to the right.
I could do that manually if I knew the width of the drawn text, but it's proving near impossible to find that.
I've read about ATSU, but I couldn't find any examples.
This sucks :/

Answer 1

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;

Answer 2

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]);
}

Answer 3

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.

Answer 4

In Swift:
let myTitle = "my title"
let titleLabel = UILabel()
let attributes: NSDictionary = [
NSFontAttributeName:UIFont(name: "HelveticaNeue-Light", size: 20),
NSForegroundColorAttributeName:UIColor.whiteColor(),
NSKernAttributeName:CGFloat(2.0)
]
let attributedTitle = NSAttributedString(string: myTitle, attributes: attributes as? [String : AnyObject])
titleLabel.attributedText = attributedTitle
titleLabel.sizeToFit()

Answer 5

Not in any publicly available version of iPhone OS. ;-) If you are a current iPhone Developer, you can get an idea of where iPhone OS is going by looking through the "What's New" notes for iPhone OS 3.2.
Update: iOS v3.2, which added support for kerning, was still under NDA when I posted this. For an update-to-date answer, see How to set kerning in iPhone UILabel.