二维码 iOS

一：生成二维码  

1.根据一个字符串生成一个二维码  根据

#import <CoreImage/CoreImage.h>这个框架写的

在按钮的点击事件写

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIImageView *imv;

@end

   // 1. 实例化二维码滤镜
   CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

    // 2. 恢复滤镜的默认属性
   [filter setDefaults];
    
    // 3. 将字符串转换成NSData
   NSData *data = [@"http://www.baidu.com" dataUsingEncoding:NSUTF8StringEncoding];

   // 4. 通过KVO设置滤镜inputMessage数据
   [filter setValue:data forKey:@"inputMessage"];

    // 5. 获得滤镜输出的图像
    CIImage *outputImage = [filter outputImage];
    UIImage *i = [UIImage imageWithCIImage:outputImage];

    // 6. 将CIImage转换成UIImage，并放大显示
     self.imv.image = i;

2.此时 就根据你写的字符串 会 生成一个对应的二维码了  但是有点模糊有没有 ？？

解决的方法来啦

//7.把图片变的更清晰
    CGRect extent = CGRectIntegral(outputImage.extent);
    CGFloat size = 100;
    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 = [CIContext contextWithOptions:nil];
    CGImageRef bitmapImage = [context createCGImage:outputImage 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);
    UIImage *i = [UIImage imageWithCGImage:scaledImage];

 清晰的有没有，^O^ 

 3.微信的二维码名片是不是有自己的logo哇，怎么弄捏

    UIImage *logoImage = [UIImage imageNamed:@"1111.png"];
  
    UIView *QRCodeView = [[UIView alloc] init];
    QRCodeView.frame = CGRectMake(0, 0, 100 , 100);

    if (logoImage != nil) {
        // 增加logo
        i = [self addImageToSuperImage:i withSubImage:logoImage andSubImagePosition:CGRectMake(20, 20, 20, 20)];
    }
    
        QRCodeView.layer.contents = (__bridge id)i.CGImage;

 这样就可以加上logo了

二：扫描二维码

用

#import <AVFoundation/AVFoundation.h>这个框架写

@interface ViewController ()<AVCaptureMetadataOutputObjectsDelegate>
@property(nonatomic,strong)AVCaptureSession *session;
@property(nonatomic,strong)AVCaptureVideoPreviewLayer *previewLayer;
@end

- (void)viewDidLoad {
    [super viewDidLoad];
    // 1. 实例化拍摄设备
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    
    // 2. 设置输入设备
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
    
    // 3. 设置元数据输出
    // 3.1 实例化拍摄元数据输出
    AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];
    // 3.3 设置输出数据代理
    [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    
    // 4. 添加拍摄会话
    // 4.1 实例化拍摄会话
    AVCaptureSession *session = [[AVCaptureSession alloc] init];
    // 4.2 添加会话输入
    [session addInput:input];
    // 4.3 添加会话输出
    [session addOutput:output];
    // 4.3 设置输出数据类型，需要将元数据输出添加到会话后，才能指定元数据类型，否则会报错
    [output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];
    
    self.session = session;
    
    // 5. 视频预览图层
    // 5.1 实例化预览图层, 传递_session是为了告诉图层将来显示什么内容
    AVCaptureVideoPreviewLayer *preview = [AVCaptureVideoPreviewLayer layerWithSession:_session];
    
    preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
    preview.frame = self.view.bounds;
    // 5.2 将图层插入当前视图
    [self.view.layer insertSublayer:preview atIndex:100];
    
    self.previewLayer = preview;
    
    // 6. 启动会话
    [_session startRunning];
}

代理方法

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
    // 会频繁的扫描，调用代理方法
    // 1. 如果扫描完成，停止会话
    [self.session stopRunning];
    // 2. 删除预览图层
    [self.previewLayer removeFromSuperlayer];
    
    NSLog(@"%@", metadataObjects);
    // 3. 设置界面显示扫描结果
    
    if (metadataObjects.count > 0) {
        AVMetadataMachineReadableCodeObject *obj = metadataObjects[0];
        // 提示：如果需要对url或者名片等信息进行扫描，可以在此进行扩展！
        //        _label.text = obj.stringValue;
        NSLog(@"%@", obj.stringValue);
    }
    
}

三：最后封装了一下生成二维码的代码  代价可以直接用

-(UIImage *)superCIImageWith:(NSString*)urlString andSuperSize:(CGFloat)puserSize andlogoImage:(UIImage *)logoImage andLogoImageLocation:(CGRect)rect
{
    // 1. 实例化二维码滤镜
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    // 2. 恢复滤镜的默认属性
    [filter setDefaults];
    
    // 3. 将字符串转换成NSData
    NSData *data = [urlString dataUsingEncoding:NSUTF8StringEncoding];
    
    // 4. 通过KVO设置滤镜inputMessage数据
    [filter setValue:data forKey:@"inputMessage"];
    
    // 5. 获得滤镜输出的图像
    CIImage *outputImage = [filter outputImage];
    
    //    UIImage *i = [UIImage imageWithCIImage:outputImage];
    // 6. 将CIImage转换成UIImage，并放大显示
    
    //7.把图片变的更清晰
    CGRect extent = CGRectIntegral(outputImage.extent);
    CGFloat scale = MIN(puserSize/CGRectGetWidth(extent), puserSize/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 = [CIContext contextWithOptions:nil];
    CGImageRef bitmapImage = [context createCGImage:outputImage 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);
    UIImage *i = [UIImage imageWithCGImage:scaledImage];
    
    
    
    
    UIView *QRCodeView = [[UIView alloc] init];
    QRCodeView.frame = CGRectMake(0, 0, 400 , 400);
    
    if (logoImage != nil) {
        // 增加logo
        i = [self addImageToSuperImage:i withSubImage:logoImage andSubImagePosition:rect];
    }
    
    QRCodeView.layer.contents = (__bridge id)i.CGImage;
    return i;

}