Ios 使用UILabel文本掩码显示UIView

我正在尝试将

ui视图

添加到

ui标签

，这样文本就是视图的遮罩，使我能够执行动画文本背景之类的操作（很像锁定屏幕上解锁标签的幻灯片）

我计划这样做的方式是使用视图的

层

上的

mask

属性将其屏蔽为文本的形状。但是，我无法找到将

UILabel

的文本形状作为

CALayer

的方法

这可能吗？我只能在

UILabel

中找到覆盖

-（void）drawRect:

方法的解决方案，但这不会给我太多的灵活性。

如果您为iOS 8+构建，则会更灵活。但是，如果您正在寻找iOS 8之前的答案，请看这里。

---

谢谢你指点我。关键是使用

CATextLayer

而不是

UILabel

目标-C:

CGRect textRect = {0, 100, self.view.frame.size.width, 100}; // rect to display the view in

CATextLayer* textMask = [CATextLayer layer];
textMask.contentsScale = [UIScreen mainScreen].scale; // sets the layer's scale to the main screen scale
textMask.frame = (CGRect){CGPointZero, textRect.size};
textMask.foregroundColor = [UIColor whiteColor].CGColor; // an opaque color so that the mask covers the text
textMask.string = @"Text Mask"; // your text here
textMask.font = (__bridge CFTypeRef _Nullable)([UIFont systemFontOfSize:30]); // your font here
textMask.alignmentMode = kCAAlignmentCenter; // centered text

UIView* view = [[UIView alloc] initWithFrame:textRect];
view.backgroundColor = [UIColor blueColor];
view.layer.mask = textMask; // mask the view to the textMask
[self.view addSubview:view];

let textRect = CGRect(x: 0, y: 100, width: view.frame.size.width, height: 100) // rect to display the view in

let textMask = CATextLayer()
textMask.contentsScale = UIScreen.mainScreen().scale // sets the layer's scale to the main screen scale
textMask.frame = CGRect(origin: CGPointZero, size: textRect.size)
textMask.foregroundColor = UIColor.whiteColor().CGColor // an opaque color so that the mask covers the text
textMask.string = "Text Mask" // your text here
textMask.font = UIFont.systemFontOfSize(30) // your font here
textMask.alignmentMode = kCAAlignmentCenter // centered text

let bgView = UIView(frame: textRect)
bgView.backgroundColor = UIColor.blueColor()
bgView.layer.mask = textMask // mask the view to the textMask
view.addSubview(bgView)

UILabel* label = [[UILabel alloc] initWithFrame:self.view.frame];
label.text = @"Label Text";
label.font = [UIFont systemFontOfSize:70];
label.textAlignment = NSTextAlignmentCenter;
label.textColor = [UIColor whiteColor];

UIView* overlayView = [[UIView alloc] initWithFrame:self.view.frame];
overlayView.backgroundColor = [UIColor blueColor];
overlayView.maskView = label;
[self.view addSubview:overlayView];

Swift:

CGRect textRect = {0, 100, self.view.frame.size.width, 100}; // rect to display the view in

CATextLayer* textMask = [CATextLayer layer];
textMask.contentsScale = [UIScreen mainScreen].scale; // sets the layer's scale to the main screen scale
textMask.frame = (CGRect){CGPointZero, textRect.size};
textMask.foregroundColor = [UIColor whiteColor].CGColor; // an opaque color so that the mask covers the text
textMask.string = @"Text Mask"; // your text here
textMask.font = (__bridge CFTypeRef _Nullable)([UIFont systemFontOfSize:30]); // your font here
textMask.alignmentMode = kCAAlignmentCenter; // centered text

UIView* view = [[UIView alloc] initWithFrame:textRect];
view.backgroundColor = [UIColor blueColor];
view.layer.mask = textMask; // mask the view to the textMask
[self.view addSubview:view];

let textRect = CGRect(x: 0, y: 100, width: view.frame.size.width, height: 100) // rect to display the view in

let textMask = CATextLayer()
textMask.contentsScale = UIScreen.mainScreen().scale // sets the layer's scale to the main screen scale
textMask.frame = CGRect(origin: CGPointZero, size: textRect.size)
textMask.foregroundColor = UIColor.whiteColor().CGColor // an opaque color so that the mask covers the text
textMask.string = "Text Mask" // your text here
textMask.font = UIFont.systemFontOfSize(30) // your font here
textMask.alignmentMode = kCAAlignmentCenter // centered text

let bgView = UIView(frame: textRect)
bgView.backgroundColor = UIColor.blueColor()
bgView.layer.mask = textMask // mask the view to the textMask
view.addSubview(bgView)

UILabel* label = [[UILabel alloc] initWithFrame:self.view.frame];
label.text = @"Label Text";
label.font = [UIFont systemFontOfSize:70];
label.textAlignment = NSTextAlignmentCenter;
label.textColor = [UIColor whiteColor];

UIView* overlayView = [[UIView alloc] initWithFrame:self.view.frame];
overlayView.backgroundColor = [UIColor blueColor];
overlayView.maskView = label;
[self.view addSubview:overlayView];

在iOS 8.0中。现在，只需创建一个

ui标签

，用作

ui视图的掩码

：

目标-C:

CGRect textRect = {0, 100, self.view.frame.size.width, 100}; // rect to display the view in

CATextLayer* textMask = [CATextLayer layer];
textMask.contentsScale = [UIScreen mainScreen].scale; // sets the layer's scale to the main screen scale
textMask.frame = (CGRect){CGPointZero, textRect.size};
textMask.foregroundColor = [UIColor whiteColor].CGColor; // an opaque color so that the mask covers the text
textMask.string = @"Text Mask"; // your text here
textMask.font = (__bridge CFTypeRef _Nullable)([UIFont systemFontOfSize:30]); // your font here
textMask.alignmentMode = kCAAlignmentCenter; // centered text

UIView* view = [[UIView alloc] initWithFrame:textRect];
view.backgroundColor = [UIColor blueColor];
view.layer.mask = textMask; // mask the view to the textMask
[self.view addSubview:view];

let textRect = CGRect(x: 0, y: 100, width: view.frame.size.width, height: 100) // rect to display the view in

let textMask = CATextLayer()
textMask.contentsScale = UIScreen.mainScreen().scale // sets the layer's scale to the main screen scale
textMask.frame = CGRect(origin: CGPointZero, size: textRect.size)
textMask.foregroundColor = UIColor.whiteColor().CGColor // an opaque color so that the mask covers the text
textMask.string = "Text Mask" // your text here
textMask.font = UIFont.systemFontOfSize(30) // your font here
textMask.alignmentMode = kCAAlignmentCenter // centered text

let bgView = UIView(frame: textRect)
bgView.backgroundColor = UIColor.blueColor()
bgView.layer.mask = textMask // mask the view to the textMask
view.addSubview(bgView)

UILabel* label = [[UILabel alloc] initWithFrame:self.view.frame];
label.text = @"Label Text";
label.font = [UIFont systemFontOfSize:70];
label.textAlignment = NSTextAlignmentCenter;
label.textColor = [UIColor whiteColor];

UIView* overlayView = [[UIView alloc] initWithFrame:self.view.frame];
overlayView.backgroundColor = [UIColor blueColor];
overlayView.maskView = label;
[self.view addSubview:overlayView];

Swift 2：

let label = UILabel.init(frame: view.frame)
label.text = "Label Text"
label.font = UIFont.systemFontOfSize(70)
label.textAlignment = .Center
label.textColor = UIColor.whiteColor()

let overlayView = UIView.init(frame: view.frame)
overlayView.backgroundColor = UIColor.blueColor()
overlayView.maskView = label

view.addSubview(overlayView)

---

这将创建一个清晰的

UILabel

，其中

UIColor.blueColor（）

color取自

overlayView

我创建了自定义maskLabel

核对答案

这就是结果。

---

有帮助吗？是的，非常感谢！我已经发布了我的实现作为答案。哦，这是对UIKit的一个很好的补充！我以前没见过。由于这更灵活，我将其标记为已接受的答案：）此外，由于问题最初标记为obj-c，我已将代码的obj-c版本添加到您的答案中。@JohnnyRockex是的，对不起！我是在yonks之前做的，忘了设置

CATextLayer

的

contentsScale

，所以在2倍或3倍的显示器上显示出来会非常糟糕。我已经纠正了这一点。