ios刮刮卡效果_iOS基础-小Demo–刮开涂层(刮刮乐效果)

刮开涂层效果.gif

设置刮开后,显示的文字Label

UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(7, 50, 400, 400)];

label.text = @”离思五首n元稹n曾经沧海难为水,n除却巫山不是云!n取次花丛懒回顾,n半缘修道半缘君!n”;

label.numberOfLines = 0;

label.backgroundColor = [UIColor colorWithRed:(arc4random()%173)/346.0 + 0.5 green:(arc4random()%173)/346.0 + 0.5 blue:(arc4random()%173)/346.0 + 0.5 alpha: 1];

label.font = [UIFont systemFontOfSize:30];

label.textAlignment = NSTextAlignmentCenter;

[self.view addSubview:label];

2. 设置遮挡在外面的Image

>“`obj

self.imageView = [[UIImageView alloc]initWithFrame:CGRectMake(7, 50, 400, 400)];

self.imageView.image = [UIImage imageNamed:@”可达鸭”];

[self.view addSubview:self.imageView ];“`

3. 在touchesMoved方法里面实现操作

>“`obj

`- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

// 触摸任意位置

UITouch *touch = touches.anyObject;

// 触摸位置在图片上的坐标

CGPoint cententPoint = [touch locationInView:self.imageView];

// 设置清除点的大小

CGRect rect = CGRectMake(cententPoint.x, cententPoint.y, 20, 20);

// 默认是去创建一个透明的视图

UIGraphicsBeginImageContextWithOptions(self.imageView.bounds.size, NO, 0);

// 获取上下文(画板)

CGContextRef ref = UIGraphicsGetCurrentContext();

// 把imageView的layer映射到上下文中

[self.imageView.layer renderInContext:ref];

// 清除划过的区域

CGContextClearRect(ref, rect);

// 获取图片

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

// 结束图片的画板, (意味着图片在上下文中消失)

UIGraphicsEndImageContext();

self.imageView.image = image;“`

相关资源：canvas实现刮刮卡效果_基于Canvas实现刮刮卡效果验证码的方法…