二维码

• 生成二维码的步骤
  
  • 导入CoreImage框架
  • 通过滤镜CIFilter生成二维码
• 二维码的内容
  
  • 纯文本
  • 名片
  • URL

---

生成二维码

• 导入 #import<CoreImage/CoreImage.h>

模糊

//1.创建滤镜对象
CIFilter * filer = [CIFilter filterWithName:@"CIQRCodeGenerator"];
//2.设置相关属性
[filer setDefaults];
//3.设置输入数据
NSString * inputData = @"YIGNORANT";
NSData * data = [inputData dataUsingEncoding:NSUTF8StringEncoding];
[filer setValue:data forKeyPath:@"inputMessage"];
//4.获取输出结果
CIImage * outputImage = [filer outputImage];
//5.显示二维码（模糊的）
self.imageView.image = [UIImage imageWithCIImage:outputImage];

清楚

- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size
{
    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;
    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];
}

---

扫描二维码

• 导入#import <AVFoundation/AVFoundation.h>
• 遵守代理AVCaptureMetadataOutputObjectsDelegate
• 定义变量
  
  • @property (weak,nonatomic) AVCaptureSession * session;
  • @property (weak,nonatomic) AVCaptureVideoPreviewLayer * layer;

    //1.创建捕捉会话
    AVCaptureSession * session = [[AVCaptureSession alloc]init];
    self.session = session;
    //2.添加输入设备
    AVCaptureDevice * device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    AVCaptureDeviceInput * input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
    [session addInput:input];
    //3.添加输出数据(实例对象（的类型）-> 类对象 -> 元类对象类型  -> 根元类对象)
    AVCaptureMetadataOutput * output = [[AVCaptureMetadataOutput alloc]init];
    [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    [session addOutput:output];
    //一定要设置元数据类型 告诉输出设备这是一个二维码  并且只能写在添加输出设备之后
    [output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];
    //4.添加一个扫描图层
    AVCaptureVideoPreviewLayer * layer = [AVCaptureVideoPreviewLayer layerWithSession:session];
    layer.frame = self.view.bounds;
    [self.view.layer addSublayer:layer];
    self.layer = layer;
    //5.开始扫描
    [session startRunning];

#pragma mark -实现output回调方法
//当扫描到数据时就会执行该方法
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{

    if (metadataObjects.count > 0) {
        //1.获取扫描结果
        AVMetadataMachineReadableCodeObject * object = [metadataObjects lastObject];
        NSLog(@"扫描到数据: %@",object.stringValue);
        //2.停止扫描
        [self.session stopRunning];
        //3.移除
        [self.layer removeFromSuperlayer];
    }else{
        NSLog(@"没有扫描到数据");
    }
}