1 #import "ViewController.h"
 2 // 默认尺寸
 3 #define SCREEN_WIDTH   [UIScreen mainScreen].bounds.size.width
 4 #define SCREENH_HeiGHT [UIScreen mainScreen].bounds.size.height
 5 #import "SecondViewController.h"
 6 @interface ViewController()
 7 
 8 @PRoPErty(nonatomic,strong)UIImageView *imageBack;// 显示底层图
 9 @property(nonatomic,strong)UIImageView *imageFont;// 显示上层图
10 @property(nonatomic,assign) BOOL isTouch;
11 
12 @end
13 
14 @implementation ViewController
15 
16 - (void)viewDidLoad {
17     [super viewDidLoad];
18     self.view.backgroundColor = [UIColor yellowColor];
19 
20     // 底层
21     self.imageBack = [[UIImageView alloc] inITWithFrame:CGRectMake(10, 84, SCREEN_WIDTH-20, SCREENH_HEIGHT-104)];
22     self.imageBack.backgroundColor = [UIColor redColor];
23     self.imageBack.image = [UIImage imageNamed:@"09B.jpg"];
24     [self.view addSubview:self.imageBack];
25     
26     // 上层
27     self.imageFont = [[UIImageView alloc] initWithFrame:self.imageBack.frame];
28     self.imageFont.backgroundColor = [UIColor clearColor];
29     self.imageFont.userInteractionEnabled = YES;
30     self.imageFont.image = [UIImage imageNamed:@"09A.jpg"];
31     [self.view addSubview:self.imageFont];
32     
33 }
34 
35 // 判断上层图片，打开触摸
36 - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
37     
38     UITouch *touch = [touches anyObject];
39     if (touch.view == self.imageFont) {
40         self.isTouch = YES;
41     }
42 }
43 
44 - (void)touchESMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
45 
46     if (self.isTouch) {
47         
48         // 开启上下文
49         UIGraphicsBeginImageContext(self.imageFont.frame.size);
50          // 将上层图片绘制到图形上下文中
51         [self.imageFont.image drawInRect:self.imageFont.bounds];
52         
53         // 清空手指触摸的位置：拿到手指，根据手指的位置，让对应的位置成为透明
54         UITouch *touch = [touches anyObject];
55         CGPoint point = [touch locationInView:touch.view];
56         
57         // 清空区域
58         CGRect rect = CGRectMake(point.x - 40, point.y - 40, 40, 40);
59         CGContextClearRect(UIGraphicsGetcurrentContext(), rect);// 清空
60         self.imageFont.image = UIGraphicsGetImageFromCurrentImageContext();
61         UIGraphicsEndImageContext();  // 关闭
62     }
63 
64 }
65 
66 - (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
67     self.isTouch = NO;
68 }
69 
70 @end