[英]CAShapeLayer mask view
I have one problem. 我有一个问题。 I look for the answers on the net and I don't understand why is not working. 我在网上寻找答案,但我不明白为什么它不起作用。 I must do some stupid mistake which I can't figure it out. 我必须犯一些愚蠢的错误,我无法弄清楚。
if I make : 如果我做:
- (void)viewDidLoad
{
[super viewDidLoad];
UIView * view = [[UIView alloc]initWithFrame:CGRectMake(10, 10, 300, 400)];
view.backgroundColor = [UIColor blueColor];
[self.view addSubview:view];
}
it create blue view on the screen, but if I make 它在屏幕上创建蓝色视图,但是如果我使
- (void)viewDidLoad
{
[super viewDidLoad];
UIView * view = [[UIView alloc]initWithFrame:CGRectMake(10, 10, 300, 400)];
view.backgroundColor = [UIColor blueColor];
[self.view addSubview:view];
CAShapeLayer * layer = [[CAShapeLayer alloc]init];
layer.frame = CGRectMake(10, 10, 30, 30);
layer.fillColor = [[UIColor blackColor] CGColor];
view.layer.mask = layer;
}
it don't show anything. 它什么也没显示。
If I understand correctly it should mask at (10,10,30,30)? 如果我理解正确,应该将其遮罩为(10,10,30,30)?
You need to set the path on the CAShapeLayer: 您需要在CAShapeLayer上设置路径:
- (void)viewDidLoad
{
[super viewDidLoad];
UIView * view = [[UIView alloc]initWithFrame:CGRectMake(10, 10, 300, 400)];
view.backgroundColor = [UIColor blueColor];
[self.view addSubview:view];
CAShapeLayer * layer = [[CAShapeLayer alloc]init];
layer.frame = view.bounds;
layer.fillColor = [[UIColor blackColor] CGColor];
layer.path = CGPathCreateWithRect(CGRectMake(10, 10, 30, 30), NULL);
view.layer.mask = layer;
}
Thanks for the answer, cncool. 感谢您的回答,cncool。
In case someone can't find suitable answer on SO for this question for hours, like i just did, i've assembled a working gist in Swift 2.2 for masking
/ clipping
UIView
with CGRect
/ UIBezierPath
: 如果有人像我刚才那样在几个小时内找不到合适的答案,就像我刚才所做的那样,我已经在Swift 2.2中组装了一个工作要点,用于使用CGRect
/ UIBezierPath
masking
/ clipping
UIView
:
https://gist.github.com/Flar49/7e977e81f1d2827f5fcd5c6c6a3c3d94 https://gist.github.com/Flar49/7e977e81f1d2827f5fcd5c6c6a3c3d94
extension UIView {
func mask(withRect rect: CGRect, inverse: Bool = false) {
let path = UIBezierPath(rect: rect)
let maskLayer = CAShapeLayer()
if inverse {
path.appendPath(UIBezierPath(rect: self.bounds))
maskLayer.fillRule = kCAFillRuleEvenOdd
}
maskLayer.path = path.CGPath
self.layer.mask = maskLayer
}
func mask(withPath path: UIBezierPath, inverse: Bool = false) {
let path = path
let maskLayer = CAShapeLayer()
if inverse {
path.appendPath(UIBezierPath(rect: self.bounds))
maskLayer.fillRule = kCAFillRuleEvenOdd
}
maskLayer.path = path.CGPath
self.layer.mask = maskLayer
}
}
Usage: 用法:
let viewSize = targetView.bounds.size
let rect = CGRect(x: 20, y: 20, width: viewSize.width - 20*2, height: viewSize.height - 20*2)
// Cuts rectangle inside view, leaving 20pt borders around
targetView.mask(withRect: rect, inverse: true)
// Cuts 20pt borders around the view, keeping part inside rect intact
targetView.mask(withRect: rect)
Hope it will save someone some time in the future :) 希望以后可以节省一些时间:)
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