IOS开发 生成二维码

//这个是我封装的方法 QCString 是将要生成的二维码的 内容 size 是大小 生成成功后返回的是 UIImage类型把它加在你需要的地方就行了

+(UIImage *)createQRForString:(NSString *)QCString withSize:(CGFloat)size{

    return [selfimageBlackToTransparent:[selfcreateNonInterpolatedUIImageFormCIImage:[selfcreateCIImageForString:QCString] withSize:size]withRed:60.0fandGreen:74.0fandBlue:89.0f];

}

//首先是二维码的生成，使用CIFilter很简单，直接传入生成二维码的字符串即可：

+ (CIImage *)createCIImageForString:(NSString *)str{

    //需要将字符串转换为utf - 8编码NSData对象

    NSData *stringData = [strdataUsingEncoding:NSUTF8StringEncoding];

    //创建CIFilter   [CIFilter filterWithName:@"CIQRCodeGenerator"]不能改变任何一点

    CIFilter *QCFilter = [CIFilterfilterWithName:@"CIQRCodeGenerator"];

    //设置内容和纠错级别

    [QCFilter setValue:stringData forKey:@"inputMessage"];

    [QCFilter setValue:@"M"forKey:@"inputCorrectionLevel"];

    //返回CIImage

    return QCFilter.outputImage;

}

// 因为生成的二维码是一个CIImage，我们直接转换成UIImage的话大小不好控制，所以使用下面方法返回需要大小的UIImage：

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

    CGRect extent = CGRectIntegral(image.extent);

    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));

    // 创建bitmap;

    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 = [CIContextcontextWithOptions:nil];

    CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];

    CGContextSetInterpolationQuality(bitmapRef,kCGInterpolationNone);

    CGContextScaleCTM(bitmapRef, scale, scale);

    CGContextDrawImage(bitmapRef, extent, bitmapImage);

    // 保存bitmap到图片

    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);

    CGContextRelease(bitmapRef);

    CGImageRelease(bitmapImage);

    return [UIImageimageWithCGImage:scaledImage];

}

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

    free((void*)data);

}

// 因为生成的二维码是黑白的，所以还要对二维码进行颜色填充，并转换为透明背景，使用遍历图片像素来更改图片颜色，因为使用的是CGContext，速度非常快：

+ (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 = [UIImageimageWithCGImage:imageRef];

    // release

    CGImageRelease(imageRef);

    CGContextRelease(context);

    CGColorSpaceRelease(colorSpace);

    return resultUIImage;

}