//#import "ViewController.h"

//

//@interface ViewController ()

//

//@end

//

//@implementation ViewController

//

//- (void)viewDidLoad {

//

//    [super viewDidLoad];

//

//    // 创建一个蓝色的Layer

//    CALayer *foregroundLayer        = [CALayer layer];

//    foregroundLayer.bounds          = CGRectMake(0, 0, 100, 100);

//    foregroundLayer.backgroundColor = [UIColor redColor].CGColor;

//

//    // 创建一个路径

//    UIBezierPath *apath = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(20, 20, 60, 60)];

//

//    // 创建maskLayer

//    CAShapeLayer *maskLayer = [CAShapeLayer layer];

//    maskLayer.path = apath.CGPath;

//    maskLayer.fillColor = [UIColor greenColor].CGColor;

//    maskLayer.fillRule = kCAFillRuleEvenOdd;

//

//    // 设置位置

//    foregroundLayer.position = self.view.center;

//    // 设置mask

//    foregroundLayer.mask = maskLayer;

//

//    [self.view.layer addSublayer:foregroundLayer];

//

//}

//

//@end

#import "ViewController.h"

static CGFloat num;

@interface ViewController ()

@property (nonatomic, strong) CAShapeLayer *circle;

@property (nonatomic, strong) CADisplayLink *link;

@end

@implementation ViewController

@synthesize circle;

- (void)viewDidLoad {

    [super viewDidLoad];

//    //创建一个CAShape

//    CALayer *bgLayer = [CALayer layer];

//

//    //设置大小颜色和位置

//    bgLayer.bounds          = CGRectMake(0, 0, 200, 200);

//    bgLayer.backgroundColor = [UIColor redColor].CGColor;

//    bgLayer.position        = self.view.center;

    CAGradientLayer *bgLayer = [CAGradientLayer layer];

    bgLayer.bounds = CGRectMake(, , , );

    bgLayer.position        = self.view.center;

    bgLayer.colors = [NSArray arrayWithObjects:

                       (id)[UIColor colorWithRed: green:/255.0 blue:/255.0 alpha:1.0].CGColor,

                       (id)[UIColor colorWithRed: green:/255.0 blue:/255.0 alpha:1.0].CGColor,

                       (id)[UIColor whiteColor].CGColor, nil];

    //创建一个CAShapeLayer作为MaskLayer

    circle = [CAShapeLayer layer];

    //设置路径

    circle.path      = [UIBezierPath bezierPathWithArcCenter:CGPointMake(, )

                                                      radius:

                                                  startAngle:

                                                    endAngle: * M_PI

                                                   clockwise:YES].CGPath;

//    circle.lineWidth = 5;

//    circle.fillColor = [UIColor greenColor].CGColor;

//    circle.fillRule  = kCAFillRuleEvenOdd;

    //设置maskLayer

    bgLayer.mask = circle;

    [self.view.layer addSublayer:bgLayer];

    //添加计时器 这个只是一个附加动画

    //self.link = [CADisplayLink displayLinkWithTarget:self selector:@selector(action)];

    //[self.link addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];

}

- (void)action {

    num ++;

    circle.path      = [UIBezierPath bezierPathWithArcCenter:CGPointMake(, )

                                                      radius: + num

                                                  startAngle:

                                                    endAngle: * M_PI

                                                   clockwise:YES].CGPath;

    if (num > ) {

        [self.link invalidate];

    }

}

@end