一、生成二维码 CoreImage框架

// 生成二维码

+ (UIImage *)generateQRCodeWithInputMessage:(NSString *)inputMessage
                                      Width:(CGFloat)width
                                     Height:(CGFloat)height{
    NSData *inputData = [inputMessage dataUsingEncoding:NSUTF8StringEncoding];
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    [filter setValue:inputData forKey:@"inputMessage"];
    //    [filter setValue:@"H" forKey:@"inputCorrectionLevel"]; // 设置二维码不同级别的容错率

    CIImage *ciImage = filter.outputImage;
    // 消除模糊
    CGFloat scaleX = MIN(width, height)/ciImage.extent.size.width;
    CGFloat scaleY = MIN(width, height)/ciImage.extent.size.height;
    ciImage = [ciImage imageByApplyingTransform:CGAffineTransformScale(CGAffineTransformIdentity, scaleX, scaleY)];
    UIImage *returnImage = [UIImage imageWithCIImage:ciImage];
    return returnImage;
}

二、生成条形码 CIFilter

// 生成条形码

+ (UIImage *)generateCode128:(NSString *)code size:(CGSize)size {
     NSData *codeData = [code dataUsingEncoding:NSUTF8StringEncoding];
 //  使用CICode128BarcodeGenerator创建filter
     CIFilter *filter = [CIFilter filterWithName:@"CICode128BarcodeGenerator" withInputParameters:@{@"inputMessage": codeData, @"inputQuietSpace": @.0}];
 // 由filter.outputImage直接转成的UIImage不太清楚，需要做高清处理
     UIImage *codeImage = [QiCodeManager scaleImage:filter.outputImage toSize:size];
     return codeImage;
}

// 缩放图片(生成高质量图片）

+ (UIImage *)scaleImage:(CIImage *)image toSize:(CGSize)size {
 //! 将CIImage转成CGImageRef
    CGRect integralRect = image.extent;// CGRectIntegral(image.extent);// 将rect取整后返回，origin取舍，size取入
    CGImageRef imageRef = [[CIContext context] createCGImage:image fromRect:integralRect];
 //! 创建上下文
    CGFloat sideScale = fminf(size.width / integralRect.size.width, size.width / integralRect.size.height) * [UIScreen mainScreen].scale;// 计算需要缩放的比例
    size_t contextRefWidth = ceilf(integralRect.size.width * sideScale);
    size_t contextRefHeight = ceilf(integralRect.size.height * sideScale);
    CGContextRef contextRef = CGBitmapContextCreate(nil, contextRefWidth, contextRefHeight, 8, 0, CGColorSpaceCreateDeviceGray(), (CGBitmapInfo)kCGImageAlphaNone);// 灰度、不透明
    CGContextSetInterpolationQuality(contextRef, kCGInterpolationNone);// 设置上下文无插值
    CGContextScaleCTM(contextRef, sideScale, sideScale);// 设置上下文缩放
    CGContextDrawImage(contextRef, integralRect, imageRef);// 在上下文中的integralRect中绘制imageRef
 //! 从上下文中获取CGImageRef
    CGImageRef scaledImageRef = CGBitmapContextCreateImage(contextRef);
    CGContextRelease(contextRef);
    CGImageRelease(imageRef);
 //! 将CGImageRefc转成UIImage
    UIImage *scaledImage = [UIImage imageWithCGImage:scaledImageRef scale:[UIScreen mainScreen].scale orientation:UIImageOrientationUp];
    return scaledImage;
}

// 合成图片（code+logo）

+ (UIImage *)combinateCodeImage:(UIImage *)codeImage andLogo:(UIImage *)logo {
    UIGraphicsBeginImageContextWithOptions(codeImage.size, YES, [UIScreen mainScreen].scale);
 // 将codeImage画到上下文中
    [codeImage drawInRect:(CGRect){.0, .0, codeImage.size.width, codeImage.size.height}];
 // 定义logo的绘制参数
    CGFloat logoSide = fminf(codeImage.size.width, codeImage.size.height) / 4;
    CGFloat logoX = (codeImage.size.width - logoSide) / 2;
    CGFloat logoY = (codeImage.size.height - logoSide) / 2;
    CGRect logoRect = (CGRect){logoX, logoY, logoSide, logoSide};
    UIBezierPath *cornerPath = [UIBezierPath bezierPathWithRoundedRect:logoRect cornerRadius:logoSide / 5];
    [cornerPath setLineWidth:2.0];
    [[UIColor whiteColor] set];
    [cornerPath stroke];
    [cornerPath addClip];
 // 将logo画到上下文中
    [logo drawInRect:logoRect];
 // 从上下文中读取image
    codeImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return codeImage;
}

原地址 https://www.jianshu.com/p/81e125a04cae

iOS 扫描相册图片二维码

https://www.jianshu.com/p/cf65be0649d9