IOS 二维码生成

#pragma mark -- 生成二维码

+ (instancetype)creatImageWithQrCodeText:(NSString *)qrT WithCreatSize:(CGFloat)size{

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

    [filter setDefaults];

    NSData *filterData = [qrT dataUsingEncoding:NSUTF8StringEncoding];

    [filter setValue:filterData forKeyPath:@"inputMessage"];

    CIImage *outPutImage = [filter outputImage];

    return [self filterTheQrCode:outPutImage WithSize:size];

}

+ (UIImage *)filterTheQrCode:(CIImage *)ciImage WithSize:(CGFloat)size{

    CGRect extent = CGRectIntegral(ciImage.extent);//获取图片的规格

    CGFloat imageWidth = CGRectGetWidth(extent);

    CGFloat imageHeight = CGRectGetHeight(extent);

    CGFloat scale = MIN(size/imageWidth, size/imageHeight);//计算像素比例

    size_t width = imageWidth*scale;

    size_t height = imageHeight*scale;

    CGColorSpaceRef csr = CGColorSpaceCreateDeviceGray();//创建一个颜色空间

    CGContextRef bitMapRef = CGBitmapContextCreate(nil, width, height, 8, 0, csr, kCGImageAlphaNone);//绘制空间的规格

    CIContext *context = [CIContext contextWithOptions:nil];//获取创建的颜色空间

    CGImageRef bitmapImage = [context createCGImage:ciImage fromRect:extent];//获取要编辑的过滤图

    CGContextSetInterpolationQuality(bitMapRef, kCGInterpolationNone);//连接颜色空间，CGInterpolationQuality表示插入的方式

    CGContextScaleCTM(bitMapRef, scale, scale);//更改过滤图的坐标

    CGContextDrawImage(bitMapRef, extent, bitmapImage);//重新绘制过滤图

    // 2.保存bitmap到图片

    CGImageRef scaledImage = CGBitmapContextCreateImage(bitMapRef);//按照绘制空间的规格生成新图片

    CGContextRelease(bitMapRef);

    CGImageRelease(bitmapImage);

    return [UIImage imageWithCGImage:scaledImage];

  }