ios - 画三角形 iOS

Question

下面的代码正在画一个圆，我如何修改现有代码来画一个三角形？

    _colorDotLayer = [CALayer layer];

    CGFloat width = self.bounds.size.width-6;
    _colorDotLayer.bounds = CGRectMake(0, 0, width, width);
    _colorDotLayer.allowsGroupOpacity = YES;
    _colorDotLayer.backgroundColor = self.annotationColor.CGColor;
    _colorDotLayer.cornerRadius = width/2;
    _colorDotLayer.position = CGPointMake(self.bounds.size.width/2, self.bounds.size.height/2);

Answer 1

虽然显示了几个 Core Graphics 解决方案，但我想添加一个基于 Core Animation 的解决方案。

- (void)viewDidLoad
{
    [super viewDidLoad];
    UIBezierPath* trianglePath = [UIBezierPath bezierPath];
    [trianglePath moveToPoint:CGPointMake(0, view3.frame.size.height-100)];
    [trianglePath addLineToPoint:CGPointMake(view3.frame.size.width/2,100)];
    [trianglePath addLineToPoint:CGPointMake(view3.frame.size.width, view2.frame.size.height)];
    [trianglePath closePath];

    CAShapeLayer *triangleMaskLayer = [CAShapeLayer layer];
    [triangleMaskLayer setPath:trianglePath.CGPath];

    UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0,0, size.width, size.height)];

    view.backgroundColor = [UIColor colorWithWhite:.75 alpha:1];
    view.layer.mask = triangleMaskLayer;
    [self.view addSubview:view];
}

代码基于我的博文。