iOS 波浪效果的實現

iOS 波浪效果的實現

@interface ViewController ()

@property (strong, nonatomic) CADisplayLink *displayLink;

@property (strong, nonatomic) CAShapeLayer *shapeLayer;

@property (strong, nonatomic) UIBezierPath *path;

@property (strong, nonatomic) CAShapeLayer *shapeLayer2;

@property (strong, nonatomic) UIBezierPath *path2;

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    _shapeLayer = [CAShapeLayer layer];

    _shapeLayer.frame = CGRectMake(0, 100, 375, 150);

    [self.view.layer addSublayer:_shapeLayer];

    _shapeLayer2 = [CAShapeLayer layer];

    _shapeLayer2.frame = CGRectMake(0, 100, 375, 150);

    [self.view.layer addSublayer:_shapeLayer2];

    _shapeLayer.fillColor = [[UIColor yellowColor] colorWithAlphaComponent:0.3].CGColor;

    _shapeLayer2.fillColor = [[UIColor blueColor] colorWithAlphaComponent:0.3].CGColor;

    _displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(drawPath)];

    [_displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];

}

- (void)drawPath {

    static double i = 0;

    CGFloat A = 10.f;//A振幅

    CGFloat k = 0;//y軸偏移

    CGFloat ω = 0.03;//角速度ω變大，則波形在X軸上收縮（波形變緊密）；角速度ω變小，則波形在X軸上延展（波形變稀疏）。不等於0

    CGFloat φ = 0 + i;//初相，x=0時的相位；反映在坐標繫上則為圖像的左右移動。

    //y=Asin(ωx+φ)+k

    _path = [UIBezierPath bezierPath];

    _path2 = [UIBezierPath bezierPath];

    [_path moveToPoint:CGPointZero];

    [_path2 moveToPoint:CGPointZero];

    for (int i = 0; i < 376; i ++) {

        CGFloat x = i;

        CGFloat y = A * sin(ω*x+φ)+k;

        CGFloat y2 = A * cos(ω*x+φ)+k;

        [_path addLineToPoint:CGPointMake(x, y)];

        [_path2 addLineToPoint:CGPointMake(x, y2)];

    }

    [_path addLineToPoint:CGPointMake(375, -100)];

    [_path addLineToPoint:CGPointMake(0, -100)];

    _path.lineWidth = 1;

    _shapeLayer.path = _path.CGPath;

    [_path2 addLineToPoint:CGPointMake(375, -100)];

    [_path2 addLineToPoint:CGPointMake(0, -100)];

    _path2.lineWidth = 1;

    _shapeLayer2.path = _path2.CGPath;

    i += 0.1;

    if (i > M_PI * 2) {

        i = 0;//防止i越界

    }

}