iOS UILabel两侧加阴影

 1 - (void)viewDidLoad

 2 {

 3     [super viewDidLoad];

 4     [self.view setBackgroundColor:[UIColor grayColor]];

 5     // Do any additional setup after loading the view, typically from a nib.

 6     MarqueeLabel *label = [[MarqueeLabel alloc]initWithFrame:CGRectMake(0, 0, 100, 20)];

 7     label.backgroundColor = [UIColor clearColor];

 8     

 9     float fadeLength = 15.0f;

10     CAGradientLayer* gradientMask = [CAGradientLayer layer];

11     gradientMask.bounds = label.layer.bounds;

12     gradientMask.position = CGPointMake([label bounds].size.width / 2, [label bounds].size.height / 2);

13     NSObject *transparent = (NSObject*) [[UIColor clearColor] CGColor];

14     NSObject *opaque = (NSObject*) [[UIColor blackColor] CGColor];

15     gradientMask.startPoint = CGPointMake(0.0, CGRectGetMidY(label.frame));

16     gradientMask.endPoint = CGPointMake(1.0, CGRectGetMidY(label.frame));

17     float fadePoint = fadeLength/label.frame.size.width;

18     [gradientMask setColors: [NSArray arrayWithObjects: transparent, opaque, opaque, transparent, nil]];

19     [gradientMask setLocations: [NSArray arrayWithObjects:

20                                  [NSNumber numberWithFloat: 0.0],

21                                  [NSNumber numberWithFloat: fadePoint],

22                                  [NSNumber numberWithFloat: 1 - fadePoint],

23                                  [NSNumber numberWithFloat: 1.0],

24                                  nil]];

25     label.layer.mask = gradientMask;

26     

27     label.text = @"者是一个测试程序测试长度适用的滚动的是就是";

28     [self.view addSubview:label];

29 }