二维码生成

自从iOS7以来,苹果已经集成了二维码的生成和识别在CoreImage中

导入头文件

#import 

生成二维码

//创建过滤器 QuickResponse Code 二维码  Generator生成
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    //恢复默认设置
    [filter setDefaults];
    //给过滤器添加数据
    NSString *inputString = @"http://www.douyu.com/315279";
    NSData *data = [inputString dataUsingEncoding:NSUTF8StringEncoding];
    [filter setValue:data forKeyPath:@"inputMessage"];
    //输出图片
    CIImage *outputImage = [filter outputImage];
    self.imageView.image = [UIImage imageWithCIImage:outputImage];

效果图

二维码.png

仔细一看会发现生成的二维码是很模糊的
通过下面的代码进行图片处理

/**
 *  根据CIImage生成指定大小的UIImage
 *
 *  @param image CIImage
 *  @param size  图片宽度
 */
- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size
{
   //将矩形的值(origin,size)都转化为整数,得到一个最小的矩形
    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;
    //创建设备依赖灰度空间
    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);
    
    // 2.保存bitmap到图片
    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
    CGContextRelease(bitmapRef);
    CGImageRelease(bitmapImage);
    return [UIImage imageWithCGImage:scaledImage];
}

效果图

处理后的二维码.png

swift版本(3.0)

/**
     生成高清二维码
     - parameter image: 需要生成原始图片
     - parameter size:  生成的二维码的宽高
     */
    fileprivate func createNonInterpolatedUIImageFormCIImage(_ image: CIImage, size: CGFloat) -> UIImage {
        
        let extent: CGRect = image.extent.integral
        let scale: CGFloat = min(size/extent.width, size/extent.height)
        
        // 1.创建bitmap;
        let width = extent.width * scale
        let height = extent.height * scale
        let cs: CGColorSpace = CGColorSpaceCreateDeviceGray()
        let bitmapRef = CGContext(data: nil, width: Int(width), height: Int(height), bitsPerComponent: 8, bytesPerRow: 0, space: cs, bitmapInfo: 0)!
        
        let context = CIContext(options: nil)
        let bitmapImage: CGImage = context.createCGImage(image, from: extent)!
        
        bitmapRef.interpolationQuality = CGInterpolationQuality.none
        bitmapRef.scaleBy(x: scale, y: scale);
        bitmapRef.draw(bitmapImage, in: extent);
        
        // 2.保存bitmap到图片
        let scaledImage: CGImage = bitmapRef.makeImage()!
        
        return UIImage(cgImage: scaledImage)
    }