iOS中的原生框架生成二维码

 1 - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
 2     
 3     //创建过滤器
 4     CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
 5     
 6     //过滤器恢复默认
 7     [filter setDefaults];
 8     
 9     //给过滤器添加数据
10     NSString *string = @"http://www.cnblogs.com/PSSSCode/";
11     
12     //将NSString格式转化成NSData格式
13     NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
14     
15     [filter setValue:data forKeyPath:@"inputMessage"];
16     
17     //获取二维码过滤器生成的二维码
18     CIImage *image = [filter outputImage];
19     
20     //将获取到的二维码添加到imageview上
21     self.imageView.image =[UIImage imageWithCIImage:image];

 1 /**
 2  *  根据CIImage生成指定大小的UIImage
 3  *
 4  *  @param image CIImage
 5  *  @param size  图片宽度
 6  */
 7 - (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size
 8 {
 9     CGRect extent = CGRectIntegral(image.extent);
10     CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
11     
12     // 1.创建bitmap;
13     size_t width = CGRectGetWidth(extent) * scale;
14     size_t height = CGRectGetHeight(extent) * scale;
15     CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
16     CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);
17     CIContext *context = [CIContext contextWithOptions:nil];
18     CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];
19     CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
20     CGContextScaleCTM(bitmapRef, scale, scale);
21     CGContextDrawImage(bitmapRef, extent, bitmapImage);
22     
23     // 2.保存bitmap到图片
24     CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
25     CGContextRelease(bitmapRef);
26     CGImageRelease(bitmapImage);
27     return [UIImage imageWithCGImage:scaledImage];
28 }