iOS 生成二维码 原生代码

- (void)viewDidLoad {

    [super viewDidLoad];

    [self stringToQRcode];

}

-(void)stringToQRcode {

    // 1.实例化二维码滤镜

    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

    

    // 2.恢复滤镜的默认属性 (因为滤镜有可能保存上一次的属性)

    [filter setDefaults];

    

    // 3.将字符串转换成NSdata

    NSString *urlString = QRCODE_HEADER(UserName);

    NSData *data  = [urlString dataUsingEncoding:NSUTF8StringEncoding];

    

    // 4.通过KVO设置滤镜, 传入data, 将来滤镜就知道要通过传入的数据生成二维码

    [filter setValue:data forKey:@"inputMessage"];

    

    // 5.生成二维码

    //输出获取的二维码

    CIImage * image = [filter outputImage];

    //CIImage转换成UIImage

    _imageview.image = [self createNonInterpolatedUIImageFormCIImage:image withSize:200];

    

}

//锐化图片效果

- (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];

}