NSArray *filters = [CIFilter filterNamesInCategory:kCICategoryBuiltIn];
NSLog(@"%@",filters);
//二维码过滤器
CIFilter *qrImageFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
//设置过滤器默认属性
[qrImageFilter setDefaults];
//将字符串转换成 NSdata (虽然二维码本质上是 字符串,但是这里需要转换,不转换就崩溃)
NSData *qrImageData = [@"看看这是什么,shenm" dataUsingEncoding:NSUTF8StringEncoding];
//我们可以打印,看过滤器的 输入属性.这样我们才知道给谁赋值
NSLog(@"%@",qrImageFilter.inputKeys);
/*
inputMessage, //二维码输入信息
inputCorrectionLevel //二维码错误的等级,就是容错率
*/
//设置过滤器的输入值 ,KVC赋值
[qrImageFilter setValue:qrImageData forKey:@"inputMessage"];
//取出图片
CIImage *qrImage = [qrImageFilter outputImage];
//但是图片 发现有的小 (27,27),我们需要放大..我们进去CIImage 内部看属性
qrImage = [qrImage imageByApplyingTransform:CGAffineTransformMakeScale(10, 10)];
//转成 UI的 类型
UIImage *qrUIImage = [UIImage imageWithCIImage:qrImage];
//----------------给 二维码 中间增加一个 自定义图片----------------
//开启绘图,获取图形上下文 (上下文的大小,就是二维码的大小)
UIGraphicsBeginImageContext(qrUIImage.size);
//把二维码图片画上去. (这里是以,图形上下文,左上角为 (0,0)点)
[qrUIImage drawInRect:CGRectMake(0, 0, qrUIImage.size.width, qrUIImage.size.height)];
//再把小图片画上去
UIImage *sImage = [UIImage imageNamed:@"麦稻首页4"];
//
// UIImageView *sImageView = [[UIImageView alloc]initWithFrame:CGRectMake(50, 50, 60, 60)];
// [self.view addSubview:sImageView];
// sImageView.image = sImage;
// // 类似于clip，使用masksToBounds阴影效果无效
// sImageView.layer.masksToBounds = YES;
// //图层的圆角半径
// sImageView.layer.cornerRadius = 50;
CGFloat sImageW = 100;
CGFloat sImageH= sImageW;
CGFloat sImageX = (qrUIImage.size.width - sImageW) * 0.5;
CGFloat sImgaeY = (qrUIImage.size.height - sImageH) * 0.5;
[sImage drawInRect:CGRectMake(sImageX, sImgaeY, sImageW, sImageH)];
//获取当前画得的这张图片
UIImage *finalyImage = UIGraphicsGetImageFromCurrentImageContext();
//关闭图形上下文
UIGraphicsEndImageContext();
//设置图片
self.erweimaImageView.image = finalyImage;
