UIBezierPath 画虚线功能

API

/**
* pattern: 虚线的长度组成
* count: 虚线的长度组成的个数
* phase: 忽略多少长度
*/
- (void)setLineDash:(nullable const CGFloat *)pattern count:(NSInteger)count phase:(CGFloat)phase;

Code

- (void)drawRect:(CGRect)rect {
    [[UIColor purpleColor] set];
    UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:self.center radius:80 startAngle:M_PI endAngle:2*M_PI  clockwise:YES];
    CGFloat lengths[2] = { 2, 5 };
    [path setLineDash:lengths count:2 phase:0];
    path.lineWidth = 10;
    [path stroke];
}

效果

D152C560-105A-4DF4-9198-7964B55A13E6.png

让虚线动起来

Code

- (instancetype)initWithFrame:(CGRect)frame{
    self = [super initWithFrame:frame];
    if (self) {
        self.backgroundColor = [UIColor whiteColor];
        CADisplayLink *link = [CADisplayLink displayLinkWithTarget:self selector:@selector(update)];
        [link addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
        
    }
    return self;
}

- (void)update{
    self.phase -= 0.25;
}

- (void)setPhase:(CGFloat)phase{
    _phase = phase;
    [self setNeedsDisplay];
}

- (void)drawRect:(CGRect)rect {
    
    [[UIColor purpleColor] set];
    UIBezierPath *path = [UIBezierPath bezierPathWithRect:CGRectMake(100, 100, 100, 100)];
    CGFloat lengths[2] = { 10, 5 };
    [path setLineDash:lengths count:2 phase:_phase];
    path.lineWidth = 3;
    [path stroke];
}

效果

line.gif