类似于刮奖的小功能,废话不多说直接上代码

-(UILabel*)textLbl{

if (_textLbl==nil ) {

_textLbl=[[UILabel alloc]init];

_textLbl.text=@"谢谢惠顾!";

_textLbl.frame=CGRectMake(100, 200, 200, 100);

_textLbl.textAlignment=NSTextAlignmentCenter;

}

return _textLbl;

}

-(UIImageView *)coatingImg{

if (_coatingImg==nil) {

_coatingImg=[[UIImageView alloc]init];

_coatingImg.image=[UIImage imageNamed:@"photo.jpg"];

_coatingImg.frame=self.textLbl.frame;

}

return _coatingImg;

}

- (void)touchesMoved:(NSSet*)touches withEvent:(nullable 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.coatingImg];

// 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.coatingImg.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.coatingImg.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.coatingImg.image = image;

}