生成二维码 iOS

扫描二维码由于他的快捷方便，成为邀请好友，添加好友等等开发中不可或缺的，下面分享一个简单的二维码生成的代码

   CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];//创建过滤器
    [filter setDefaults];//恢复默认
    NSString *datastring = _shareUrl;
    NSData *data = [datastring dataUsingEncoding:NSUTF8StringEncoding];//给滤镜添加数据
    [filter setValue:data forKey:@"inputMessage"];
    CIImage *outputImage = [filter outputImage];
    UIImageView * erweimaImg;//创建一个二维码的imageView
    erweimaImg.image = [self createNonInterpolatedUIImageFormCIImage:outputImage withSize:125];

//生成二维码滤镜
- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size{
    CGRect extent = CGRectIntegral(image.extent);
    CGFloat  scale = MIN(size/CGRectGetWidth(extent),size/CGRectGetHeight(extent));
    size_t width = CGRectGetWidth(extent) * scale;
    size_t height = CGRectGetHeight(extent) * scale;
    CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
    //创建bitmap
    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];
}