iOS根据URL生成二维码

- (void)createQRcodWithUrl:(NSString *)url{

    

    // 1.创建过滤器

    CIFilter *filter = [CIFilterfilterWithName:@"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 = @"http://www.520it.com";

    NSData *data = [urldataUsingEncoding:NSUTF8StringEncoding];

    [filter setValue:dataforKeyPath:@"inputMessage"];

    // 4.获取输出的二维码

    CIImage *outputImage = [filteroutputImage];

    // 5.将CIImage转换成UIImage，并放大显示

    self.qrCodImgView.image = [self createNonInterpolatedUIImageFormCIImage:outputImagewithSize:100];

    

}

/**

 * 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 = [CIContextcontextWithOptions:nil];

    CGImageRef bitmapImage = [contextcreateCGImage: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 [UIImageimageWithCGImage:scaledImage];

}