用UIBezierPath数组对UIView进行镂空处理

效果

源码

//
//  CutOutClearView.h
//  CutOutMaskView
//
//  Created by YouXianMing on 16/7/8.
//  Copyright © 2016年 YouXianMing. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface CutOutClearView : UIView

@property (nonatomic, strong) UIColor  *fillColor;
@property (nonatomic, strong) NSArray  <UIBezierPath *>  *paths;

@end

//
//  CutOutClearView.m
//  CutOutMaskView
//
//  Created by YouXianMing on 16/7/8.
//  Copyright © 2016年 YouXianMing. All rights reserved.
//

#import "CutOutClearView.h"

@implementation CutOutClearView

- (instancetype)initWithFrame:(CGRect)frame {

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

        self.fillColor       = [UIColor whiteColor];
        self.backgroundColor = [UIColor clearColor];
        self.opaque          = NO;
    }

    return self;
}

- (void)drawRect:(CGRect)rect {

    [super drawRect:rect];

    [self.fillColor setFill];
    UIRectFill(rect);

    CGContextRef context = UIGraphicsGetCurrentContext();

    for (UIBezierPath *path in self.paths) {

        CGContextAddPath(context, path.CGPath);
        CGContextSetBlendMode(context, kCGBlendModeClear);
        CGContextFillPath(context);
    }
}

@end

//
//  ViewController.m
//  CutOutClearView
//
//  Created by YouXianMing on 16/7/8.
//  Copyright © 2016年 YouXianMing. All rights reserved.
//

#import "ViewController.h"
#import "CutOutClearView.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    UIImageView *imageView = [[UIImageView alloc] initWithFrame:self.view.bounds];
    imageView.image        = [UIImage imageNamed:@"bg.png"];
    imageView.contentMode  = UIViewContentModeScaleAspectFill;
    [self.view addSubview:imageView];

    NSMutableArray *paths = [NSMutableArray array];

    {
        UIBezierPath* bezierPath = [UIBezierPath bezierPath];
        [bezierPath moveToPoint: CGPointMake(57.04, 31.19)];
        [bezierPath addLineToPoint: CGPointMake(125.55, 12.5)];
        [bezierPath addLineToPoint: CGPointMake(185.5, 91)];
        [bezierPath addLineToPoint: CGPointMake(57.04, 169.5)];
        [bezierPath addLineToPoint: CGPointMake(18.5, 91)];
        [bezierPath addLineToPoint: CGPointMake(57.04, 31.19)];
        [bezierPath closePath];
        [paths addObject:bezierPath];
    }

    {
        UIBezierPath* bezierPath = [UIBezierPath bezierPath];
        [bezierPath moveToPoint: CGPointMake(46.5, 245.5)];
        [bezierPath addLineToPoint: CGPointMake(137.5, 272.5)];
        [bezierPath addLineToPoint: CGPointMake(137.5, 211.5)];
        [bezierPath addLineToPoint: CGPointMake(90.5, 196.5)];
        [bezierPath addLineToPoint: CGPointMake(46.5, 211.5)];
        [bezierPath addLineToPoint: CGPointMake(46.5, 245.5)];
        [bezierPath closePath];
        [paths addObject:bezierPath];
    }

    CutOutClearView *cutOutView = [[CutOutClearView alloc] initWithFrame:self.view.bounds];
    cutOutView.fillColor        = [UIColor redColor];
    cutOutView.paths            = paths;
//    [self.view addSubview:cutOutView];
    imageView.maskView = cutOutView;
}

@end

细节