iOS中url生成二维码

// 1.创建过滤器
CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

// 2.恢复默认
[filter setDefaults];

// 3.给过滤器添加数据(正则表达式/账号和密码)
NSString *dataString = url;
NSData *data = [dataString dataUsingEncoding:NSUTF8StringEncoding];
[filter setValue:data forKey:@"inputMessage"];

// 4.获取输出的二维码
CIImage *outputImage = [filter outputImage];

//m_codeView.image = [UIImage imageWithCIImage:outputImage];
// 5.显示二维码
m_codeView.image = [self createNonInterpolatedUIImageFormCIImage:outputImage withSize:200];

//6.添加长按手势
UILongPressGestureRecognizer *gesture=[[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longPress:)];
gesture.minimumPressDuration=1.0f;
gesture.numberOfTouchesRequired = 1;
m_codeView.userInteractionEnabled=YES;
[m_codeView addGestureRecognizer:gesture];

/**
  *  根据CIImage生成指定大小的UIImage
 *
 *  @param image CIImage
 *  @param size  图片宽度
 */
 - (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size {
CGRect extent = CGRectIntegral(image.extent);
CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));

// 1.创建bitmap;
size_t width = CGRectGetWidth(extent) * scale;
size_t height = CGRectGetHeight(extent) * scale;
CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);
CIContext *context = [CIContext contextWithOptions:nil];
CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];
CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
CGContextScaleCTM(bitmapRef, scale, scale);
CGContextDrawImage(bitmapRef, extent, bitmapImage);

// 2.保存bitmap到图片
CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
CGContextRelease(bitmapRef);
CGImageRelease(bitmapImage);
return [UIImage imageWithCGImage:scaledImage];
}