iOS开发之生成二维码

记录一下生成二维码

第一步:导入#import
第二步:调用方法

//生成二维码
- (UIImage *)generateQRCodeWithString:(NSString *)string Size:(CGFloat)size
{
    //创建过滤器
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    //过滤器恢复默认
    [filter setDefaults];
    //给过滤器添加数据<字符串长度893>
    NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
    [filter setValue:data forKey:@"inputMessage"];
    //获取二维码过滤器生成二维码
    CIImage *image = [filter outputImage];
    UIImage *img = [self createNonInterpolatedUIImageFromCIImage:image WithSize:size];
    return img;
}

第三步:用生成的模糊图片重新生成清晰图片

//二维码清晰
- (UIImage *)createNonInterpolatedUIImageFromCIImage:(CIImage *)image WithSize:(CGFloat)size
{
    CGRect extent = CGRectIntegral(image.extent);
    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
    
    //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);
    
    //保存图片
    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
    CGContextRelease(bitmapRef);
    CGImageRelease(bitmapImage);
    return [UIImage imageWithCGImage:scaledImage];
}

网上也有很多相关文章,我这里就是记录一下,