二维码工具类

【实例简介】二维码工具类
【实例截图】
【核心代码】

#import "LCQRCodeUtil.h"

@implementation LCQRCodeUtil

#pragma mark 读取图片二维码
/**
 *  读取图片中二维码信息
 *
 *  @param image 图片
 *
 *  @return 二维码内容
 */
(NSString *)readQRCodeFromImage:(UIImage *)image{
    NSData *data = UIImagePNGRepresentation(image);
    CIImage *ciimage = [CIImage imageWithData:data];
    if (ciimage) {
        CIDetector *qrDetector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:[CIContext contextWithOptions:@{kCIContextUseSoftwareRenderer:@(YES)}] options:@{CIDetectorAccuracy : CIDetectorAccuracyHigh}];
        NSArray *resultArr = [qrDetector featuresInImage:ciimage];
        if (resultArr.count >0) {
            CIFeature *feature = resultArr[0];
            CIQRCodeFeature *qrFeature = (CIQRCodeFeature *)feature;
            NSString *result = qrFeature.messageString;
            
            return result;
        }else{
            return nil;
        }
    }else{
        return nil;
    }
}

#pragma mark 生成二维码
/**
 *  生成二维码图片
 *
 *  @param QRString  二维码内容
 *  @param sizeWidth 图片size（正方形）
 *  @param color     填充色
 *
 *  @return  二维码图片
 */
(UIImage *)createQRimageString:(NSString *)QRString sizeWidth:(CGFloat)sizeWidth fillColor:(UIColor *)color{
    CIImage *ciimage = [self createQRForString:QRString];
    UIImage *qrcode = [self createNonInterpolatedUIImageFormCIImage:ciimage withSize:sizeWidth];
    if (color) {
        CGFloat R=0, G=0, B=0;
        
        CGColorRef colorRef = [color CGColor];
        long numComponents = CGColorGetNumberOfComponents(colorRef);
        
        if (numComponents == 4)
        {
            const CGFloat *components = CGColorGetComponents(colorRef);
            R = components[0];
            G = components[1];
            B = components[2];
        }
        
        UIImage *customQrcode = [self imageBlackToTransparent:qrcode withRed:R andGreen:G andBlue:B];
        return customQrcode;
    }
    
    return qrcode;

}
#pragma mark - QRCodeGenerator
(CIImage *)createQRForString:(NSString *)qrString {
    // Need to convert the string to a UTF-8 encoded NSData object
    NSData *stringData = [qrString dataUsingEncoding:NSUTF8StringEncoding];
    // Create the filter
    CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    // Set the message content and error-correction level
    [qrFilter setValue:stringData forKey:@"inputMessage"];
    [qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"];
    // Send the image back
    return qrFilter.outputImage;
}


#pragma mark - InterpolatedUIImage
(UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size {
    CGRect extent = CGRectIntegral(image.extent);
    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
    // create a bitmap image that we'll draw into a bitmap context at the desired size;
    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);
    // Create an image with the contents of our bitmap
    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
    // Cleanup
    CGContextRelease(bitmapRef);
    CGImageRelease(bitmapImage);
    return [UIImage imageWithCGImage:scaledImage];
}

#pragma mark - imageToTransparent
void ProviderReleaseData (void *info, const void *data, size_t size){
    free((void*)data);
}
(UIImage*)imageBlackToTransparent:(UIImage*)image withRed:(CGFloat)red andGreen:(CGFloat)green andBlue:(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 colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpace,
                                                 kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);
    CGContextDrawImage(context, 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;
        }
    }
    // context to image
    CGDataProviderRef dataProvider = CGDataProviderCreateWithData(NULL, rgbImageBuf, bytesPerRow * imageHeight, ProviderReleaseData);
    CGImageRef imageRef = CGImageCreate(imageWidth, imageHeight, 8, 32, bytesPerRow, colorSpace,
                                        kCGImageAlphaLast | kCGBitmapByteOrder32Little, dataProvider,
                                        NULL, true, kCGRenderingIntentDefault);
    CGDataProviderRelease(dataProvider);
    UIImage* resultUIImage = [UIImage imageWithCGImage:imageRef];
    // release
    CGImageRelease(imageRef);
    CGContextRelease(context);
    CGColorSpaceRelease(colorSpace);
    return resultUIImage;
}

@end