Specialized Layers - iOS Core Animation - page 108

attributes, but because the point of the exercise is to demonstrate that this feature also
works on iOS 5 and below, we've used the Core Text equivalents instead. This means that
you'll need to add the Core Text framework to your project; otherwise, the compiler won't
recognize the attribute constants.
Figure 6.4 shows the result. (Note the red, underlined text.)
Listing 6.3 Implementing a Rich Text Label Using NSAttributedString
#import "DrawingView.h"
#import <QuartzCore/QuartzCore.h>
#import <CoreText/CoreText.h>
@interface ViewController ()
@property ( nonatomic , weak ) IBOutlet UIView *labelView;
@end
@implementation ViewController
- ( void )viewDidLoad
{
[ super viewDidLoad ];
//create a text layer
CATextLayer *textLayer = [ CATextLayer layer ];
textLayer. frame = self . labelView . bounds ;
textLayer. contentsScale = [ UIScreen mainScreen ]. scale ;
[ self . labelView . layer addSublayer :textLayer];
//set text attributes
textLayer. alignmentMode = kCAAlignmentJustified ;
textLayer. wrapped = YES ;
//choose a font
UIFont *font = [ UIFont systemFontOfSize : 15 ];
//choose some text
NSString *text = @"Lorem ipsum dolor sit amet, consectetur adipiscing \
elit. Quisque massa arcu, eleifend vel varius in, facilisis pulvinar \
leo. Nunc quis nunc at mauris pharetra condimentum ut ac neque. Nunc \
elementum, libero ut porttitor dictum, diam odio congue lacus, vel \
fringilla sapien diam at purus. Etiam suscipit pretium nunc sit amet \
lobortis" ;