其中有一个不太规则的label：

image.png

这个label顶部的两个角是圆角，底部的两个角是直角，底部还有一个小三角。

思路

CAShapeLayer联合UIBezierPath画一个不规则的layer作为label.layer的mask。

具体实现

1.自定义一个继承自UILabel的IrregularLabel

import "IrregularLabel.h"

@interface IrregularLabel ()

/** 遮罩 */

@property (nonatomic, strong) CAShapeLayer *maskLayer;

/** 路径 */

@property (nonatomic, strong) UIBezierPath *borderPath;

@end

2.在初始化方法中进行相应初始化和设置

• (instancetype)initWithFrame:(CGRect)frame {

  if (self = [super initWithFrame:frame]) {

    // 初始化遮罩
  
    self.maskLayer = [CAShapeLayer layer];
  
    // 设置遮罩
  
    [self.layer setMask:self.maskLayer];
  
    // 初始化路径
  
    self.borderPath = [UIBezierPath bezierPath];
  

  }

  return self;

}

3.在layoutSubviews方法中进行路径的设置

• (void)layoutSubviews {

  [super layoutSubviews];

  // 遮罩层frame

  self.maskLayer.frame = self.bounds;

  // 设置path起点

  [self.borderPath moveToPoint:CGPointMake(0, 10)];

  // 左上角的圆角

  [self.borderPath addQuadCurveToPoint:CGPointMake(10, 0) controlPoint:CGPointMake(0, 0)];

  // 直线，到右上角

  [self.borderPath addLineToPoint:CGPointMake(self.bounds.size.width - 10, 0)];

  // 右上角的圆角

  [self.borderPath addQuadCurveToPoint:CGPointMake(self.bounds.size.width, 10) controlPoint:CGPointMake(self.bounds.size.width, 0)];

  // 直线，到右下角

  [self.borderPath addLineToPoint:CGPointMake(self.bounds.size.width, self.bounds.size.height)];

  // 底部的小三角形

  [self.borderPath addLineToPoint:CGPointMake(self.bounds.size.width/2+5, self.bounds.size.height)];

  [self.borderPath addLineToPoint:CGPointMake(self.bounds.size.width/2, self.bounds.size.height-5)];

  [self.borderPath addLineToPoint:CGPointMake(self.bounds.size.width/2 - 5, self.bounds.size.height)];

  // 直线，到左下角

  [self.borderPath addLineToPoint:CGPointMake(0, self.bounds.size.height)];

  // 直线，回到起点

  [self.borderPath addLineToPoint:CGPointMake(0, 10)];

  // 将这个path赋值给maskLayer的path

  self.maskLayer.path = self.borderPath.CGPath;

}

左上角的坐标是(0,0)

右下角的坐标是(maxX,maxY)

圆角是用的二次贝塞尔曲线，关于二次贝塞尔曲线，我在网上看到一张比较形象的图：

image

最终效果

• (void)viewDidLoad {

  [super viewDidLoad];

  // Do any additional setup after loading the view, typically from a nib.

  self.label = [[IrregularLabel alloc] initWithFrame:CGRectMake(90, 200, 200, 40)];

  [self.view addSubview:self.label];

  self.label.text = @"这是一个不规则label";

  self.label.textAlignment = NSTextAlignmentCenter;

  self.label.backgroundColor = [UIColor redColor];

  self.label.textColor = [UIColor whiteColor];

  self.label.font = [UIFont boldSystemFontOfSize:16];

}

效果图：

image

demo

https://github.com/CaiWanFeng/IrregularLabel