iOS 波浪效果

• 效果

  
  波浪效果

• WaveView.h

#import <UIKit/UIKit.h>

@interface WaveView : UIView

@property (nonatomic, assign) CGFloat alpha; // 振幅A
@property (nonatomic, assign) CGFloat omega; // 角速度ω
@property (nonatomic, assign) CGFloat phi; //初相φ
@property (nonatomic, assign) CGFloat kappa; //偏距k
@property (nonatomic, assign) CGFloat speed; // 移动速度

@end

• WaveView.m

#import "WaveView.h"

@interface WaveView ()

@property (nonatomic, strong) CADisplayLink *displayLink;

@end

@implementation WaveView

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        self.backgroundColor = [UIColor cyanColor];
        self.alpha = self.bounds.size.height * 0.1;
        self.omega = M_PI * 2 / self.bounds.size.width;
        self.phi = 0;
        self.kappa = self.bounds.size.height * 0.5;
        self.speed = 5;
        self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(handleDisplay)];
        [self.displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
    }
    return self;
}

#pragma mark - private method
- (void)handleDisplay
{
    if (!self.isHidden) {
        self.phi -= self.speed * self.omega;
        [self setNeedsDisplay];
    }
}


// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    
    CGContextRef cxt = UIGraphicsGetCurrentContext();
    //初始化运动路径
    CGMutablePathRef path = CGPathCreateMutable();
    //设置起始位置
    CGPathMoveToPoint(path, nil, 0, self.bounds.size.height);
    //正弦曲线公式为：y=Asin(ωx+φ)+k;
    for (CGFloat x = 0.0f; x <= self.bounds.size.width; x++) {
        CGFloat y = self.alpha * sinf(self.omega * x + self.phi) + self.kappa;
        CGPathAddLineToPoint(path, nil, x, y);
    }
    CGPathAddLineToPoint(path, nil, self.bounds.size.width, self.bounds.size.height);
    CGPathCloseSubpath(path);
    //绘制曲线
    CGContextSetFillColorWithColor(cxt, [UIColor orangeColor].CGColor);
    CGContextSetLineWidth(cxt, 0.5);
    CGContextAddPath(cxt, path);
    CGContextFillPath(cxt);
    CGPathRelease(path);
    
}

• 实现

WaveView *waveView = [[WaveView alloc] initWithFrame:CGRectMake(150, 150, 100, 100)];
    waveView.alpha = 10;
    waveView.kappa = 50;
    waveView.speed = 1.0f;
    waveView.layer.masksToBounds = YES;
    waveView.layer.cornerRadius = 50;
    [self.view addSubview:waveView];