iOS 二维码生成 改变颜色 添加中心图

　　iOS 二维码生成 改变颜色 添加中心图

#pragma mark - 生成二维码图片
+ (UIImage *)qrImageForString:(NSString *)string imageSize:(CGFloat)Imagesize logoImageSize:(CGFloat)waterImagesize{
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    [filter setDefaults];
    NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
    [filter setValue:data forKey:@"inputMessage"];//通过kvo方式给一个字符串，生成二维码
    [filter setValue:@"H" forKey:@"inputCorrectionLevel"];//设置二维码的纠错水平，越高纠错水平越高，可以污损的范围越大
    CIImage *outPutImage = [filter outputImage];//拿到二维码图片
    return [[self alloc] createNonInterpolatedUIImageFormCIImage:outPutImage withSize:Imagesize waterImageSize:waterImagesize];
}

- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size waterImageSize:(CGFloat)waterImagesize{
    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;
    //创建一个DeviceGray颜色空间
    CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
    //CGBitmapContextCreate(void * _Nullable data, size_t width, size_t height, size_t bitsPerComponent, size_t bytesPerRow, CGColorSpaceRef  _Nullable space, uint32_t bitmapInfo)
    //width：图片宽度像素
    //height：图片高度像素
    //bitsPerComponent：每个颜色的比特值，例如在rgba-32模式下为8
    //bitmapInfo：指定的位图应该包含一个alpha通道。
    CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);
    CIContext *context = [CIContext contextWithOptions:nil];
    //创建CoreGraphics image
    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);
    
    //原图
    UIImage *outputImage = [UIImage imageWithCGImage:scaledImage];
    
    outputImage = [UIImage specialColorImage:outputImage withRed:102 green:102 blue:102];
    //给二维码加 logo 图
    UIGraphicsBeginImageContextWithOptions(outputImage.size, NO, [[UIScreen mainScreen] scale]);
    [outputImage drawInRect:CGRectMake(0,0 , size, size)];
    //logo图
    UIImage *waterimage = [UIImage imageNamed:@"applogo"];
    //把logo图画到生成的二维码图片上，注意尺寸不要太大（最大不超过二维码图片的%30），太大会造成扫不出来
    [waterimage drawInRect:CGRectMake((size-waterImagesize)/2.0, (size-waterImagesize)/2.0, waterImagesize, waterImagesize)];
    UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newPic;
}

void ProviderReleaseData (void *info, const void *data, size_t size){
     free((void*)data);
}

//改变二维码颜色
+ (UIImage *)specialColorImage:(UIImage *)image withRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue {
    const int imageWidth = image.size.width;
    const int imageHeight = image.size.height;
    size_t bytesPerRow = imageWidth * 4;
    uint32_t* rgbImageBuf = (uint32_t*)malloc(bytesPerRow * imageHeight);
    
    //Create context
    CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
    CGContextRef contextRef = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpaceRef, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);
    CGContextDrawImage(contextRef, CGRectMake(0, 0, imageWidth, imageHeight), image.CGImage);
    
    //Traverse pixe
    int pixelNum = imageWidth * imageHeight;
    uint32_t* pCurPtr = rgbImageBuf;
    for (int i = 0; i < pixelNum; i++, pCurPtr++){
        if ((*pCurPtr & 0xFFFFFF00) < 0x99999900){
            //Change color
            uint8_t* ptr = (uint8_t*)pCurPtr;
            ptr[3] = red; //0~255
            ptr[2] = green;
            ptr[1] = blue;
        }else{
            uint8_t* ptr = (uint8_t*)pCurPtr;
            ptr[0] = 0;
        }
    }
    CGDataProviderRef dataProviderRef = CGDataProviderCreateWithData(NULL, rgbImageBuf, bytesPerRow * imageHeight,ProviderReleaseData);
    CGImageRef imageRef = CGImageCreate(imageWidth, imageHeight, 8, 32, bytesPerRow, colorSpaceRef,
                                        kCGImageAlphaLast | kCGBitmapByteOrder32Little, dataProviderRef,
                                        NULL, true, kCGRenderingIntentDefault);
    CGDataProviderRelease(dataProviderRef);
    UIImage* img = [UIImage imageWithCGImage:imageRef];
    
    //Release
    CGImageRelease(imageRef);
    CGContextRelease(contextRef);
    CGColorSpaceRelease(colorSpaceRef);
    return img;
}