贝塞尔路径和遮罩技术

Question

我可以帮助您将UIBezierPath设置为视图的蒙版： 目标是这样的： 因此，我使用以下框架绘制视图：

CGFloat round = 80;
UIView *myView = [[UIView alloc] initWithFrame:CGRectMake(self.frame.size.width/2-105, 0, 210, 60+round)];
myView.backgroundColor = [UIColor redColor];

然后尝试添加BezierMask：

UIBezierPath *aPath = [UIBezierPath bezierPath];

CGSize viewSize = CGSizeMake(myView.frame.size.width, myView.frame.size.height); //(210,80)
CGPoint startPoint = CGPointMake(myView.frame.origin.x,myView.frame.origin.y); //(279,0)

[aPath moveToPoint:startPoint]; //(279,0)

[aPath addLineToPoint:CGPointMake(startPoint.x+viewSize.width,startPoint.y)]; //(489,0)
[aPath addLineToPoint:CGPointMake(startPoint.x+viewSize.width,startPoint.y+viewSize.height-round)]; //(489,60)
[aPath addQuadCurveToPoint:CGPointMake(startPoint.x,startPoint.y+viewSize.height-round) controlPoint:CGPointMake(startPoint.x+(viewSize.width/2),80)]; //(279,60) : (384,80)

[aPath closePath];

CAShapeLayer *layer = [CAShapeLayer layer];
layer.frame = myView.bounds;
layer.path = aPath.CGPath;
myView.layer.mask = layer;

[self addSubview:myView];

但是之后我的视图消失了。为什么？

- Jakub

Answer 1

我猜您对蒙版层使用的坐标不正确。您的蒙版层必须放置在它所遮盖的视图内，而不是视图的父视图中。

尝试以下更改：

CGSize viewSize = myView.bounds.size;
CGPoint startPoint = CGPointZero;

你的代码进行了一些小修改后对我来说运行正常。

- Lukas Kukacka

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哦，谢谢。没意识到那必须是0,0点。谢谢。 - Jakub