第一种：生成普通二维码

方法的调用（这个方法生成普通的二维码）：

 UIImage *image = [UIImage df_createNonInterpolatedUIImageFormCIImage:[UIImage df_createQRcodeWithUrlstring:@"https://www.baidu.com"] withSize:150];  [self.qrImageView setImage:image];

/**

 *生成二维码

 */

+ (CIImage *)df_createQRcodeWithUrlstring:(NSString *)urlString{

    // 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)

    [filtersetDefaults];

    // 3.将字符串转换成NSdata

    NSData*data  = [urlStringdataUsingEncoding: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

    [filtersetValue:data forKey:@"inputMessage"];

    // 5.生成二维码

    CIImage*outputImage = [filteroutputImage];

    returnoutputImage;

}

+ (UIImage *)df_createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat)size{

    CGRect extent = CGRectIntegral(image.extent);

    CGFloatscale =MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));

    // 1.创建bitmap;

    size_twidth =CGRectGetWidth(extent) * scale;

    size_theight =CGRectGetHeight(extent) * scale;

    CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();

    CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);

    CIContext *context = [CIContext contextWithOptions:nil];

    CGImageRefbitmapImage = [contextcreateCGImage:imagefromRect: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];

}

 添加logo

方法调用(这个方法可以生成带图片的二维码，建议用第2种方法)：

UIImage *image = [UIImage df_drawImage:[UIImage imageNamed:@"XXX"] inImage:[UIImage df_createNonInterpolatedUIImageFormCIImage:[UIImage df_createQRcodeWithUrlstring:@"https://www.baidu.com"] withSize:150]]; [self.qrImageView setImage:image];

+ (UIImage *)df_drawImage:(UIImage *)newImage inImage:(UIImage *)sourceImage;

+ (UIImage *)df_drawImage:(UIImage *)newImage inImage:(UIImage *)sourceImage {

    CGSizeimageSize;//画的背景 大小

    imageSize = [sourceImagesize];

    UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0.0);

    [sourceImagedrawAtPoint:CGPointMake(0,0)];

    //获得 图形上下文

    CGContextRef context=UIGraphicsGetCurrentContext();

    //画 自己想要画的内容(添加的图片)

    CGContextDrawPath(context, kCGPathStroke);

    // 注意logo的尺寸不要太大,否则可能无法识别

    CGFloatcenterW=sourceImage.size.width*0.25;

    CGFloatcenterH=centerW;

    CGFloatcenterX=(sourceImage.size.width-centerW)*0.5;

    CGFloatcenterY=(sourceImage.size.height-centerH)*0.5;

    CGRectrect =CGRectMake(centerX, centerY, centerW, centerH);

//    CGContextAddEllipseInRect(context, rect);

    CGContextClip(context);

    [newImagedrawInRect:rect];

    //返回绘制的新图形

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    returnimage;

}

第二种：生成带图片的二维码

方法调用（这个方法可以生成带图片的二维码，建议用这个）：

 [self.qrImageView setImage:[UIImage df_createInterpolatedUIImageFormCIImageWithUrlstring:@"XXX" withSize:150 iamgeName:@"XXX"]];

+ (UIImage *)df_createInterpolatedUIImageFormCIImageWithUrlstring:(NSString *)urlString withSize:(CGFloat)size iamgeName:(NSString *)imageName{

    // 1. 创建一个二维码滤镜实例(CIFilter)

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

    // 滤镜恢复默认设置

    [filtersetDefaults];

    // 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)

    [filtersetDefaults];

    // 3.将字符串转换成NSdata

    NSData*data  = [urlStringdataUsingEncoding: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

    [filtersetValue:data forKey:@"inputMessage"];

    // 5.生成二维码

    CIImage*image = [filteroutputImage];

    //4.在中心增加一张图片

    UIImage *img = [UIImage df_createNonInterpolatedUIImageFormCIImage:image withSize:size];

    //5.把中央图片划入二维码里面

    //5.1开启图形上下文

    UIGraphicsBeginImageContext(img.size);

    //5.2将二维码的图片画入

    [imgdrawInRect:CGRectMake(0, 0, img.size.width, img.size.height)];

    UIImage*centerImg = [UIImageimageNamed:imageName];

    CGFloatcenterW=img.size.width*0.25;

    CGFloatcenterH=centerW;

    CGFloatcenterX=(img.size.width-centerW)*0.5;

    CGFloatcenterY=(img.size.height-centerH)*0.5;

    [centerImgdrawInRect:CGRectMake(centerX, centerY, centerW, centerH)];

    //5.3获取绘制好的图片

    UIImage *finalImg=UIGraphicsGetImageFromCurrentImageContext();

    //5.4关闭图像上下文

    UIGraphicsEndImageContext();

    return  finalImg;

}