欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页

原生二维码扫描

程序员文章站 2022-07-14 18:19:04
...

原生二维码扫描

个人是比较支持用原生二维码扫描的,这里也就仅仅以原生二维码扫面为范例。另也有二维码扫描库ZBarSDK(点这里) ZXingObjC(点这里)

1.原生扫描用到的几个类

@property (strong,nonatomic)AVCaptureDevice * device;
@property (strong,nonatomic)AVCaptureDeviceInput * input;
@property (strong,nonatomic)AVCaptureMetadataOutput * output;
@property (strong,nonatomic)AVCaptureSession * session;
@property (strong,nonatomic)AVCaptureVideoPreviewLayer * preview;

2.在viewDidLoad里创建它们

// Device
_device = [AVCaptureDevicedefaultDeviceWithMediaType:AVMediaTypeVideo];

// Input
_input = [AVCaptureDeviceInputdeviceInputWithDevice:self.deviceerror:nil];

// Output
_output = [[AVCaptureMetadataOutputalloc]init];
[_outputsetMetadataObjectsDelegate:selfqueue:dispatch_get_main_queue()];

// Session
_session = [[AVCaptureSessionalloc]init];
[_sessionsetSessionPreset:AVCaptureSessionPresetHigh];

连接输入和输出

if ([_sessioncanAddInput:self.input])
{
    [_sessionaddInput:self.input];
}

if ([_sessioncanAddOutput:self.output])
{
    [_sessionaddOutput:self.output];
}

设置条码类型

_output.metadataObjectTypes aaa@qq.com[AVMetadataObjectTypeQRCode];

添加扫描画面

_preview =[AVCaptureVideoPreviewLayerlayerWithSession:_session];
_preview.videoGravity =AVLayerVideoGravityResizeAspectFill;
_preview.frame =self.view.layer.bounds;
[self.view.layerinsertSublayer:_previewatIndex:0];

开始扫描

[_sessionstartRunning];

最后实现协议AVCaptureMetadataOutputObjectsDelegate

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
   NSString *stringValue;
   if ([metadataObjectscount] >0){
   //停止扫描
   [_sessionstopRunning];        
   AVMetadataMachineReadableCodeObject * metadataObject = [metadataObjectsobjectAtIndex:0];
   stringValue = metadataObject.stringValue;        
  }
}

到了这一步就可以成功扫描二维码了

还有一个小问题需要说明一下,之前写过一篇限制二维码扫描区域的,在这里稍微提一下。如下图微信扫描,把扫描范围限制在中间的方框内

原生二维码扫描
微信二维码扫描

要想限制二维码扫描区域,需要设置一个参数rectOfInterest 这个参数有点特别,这个参数的React 与平常设置的坐标系是完全相反的,即X与Y互换、W与H互换。

设置的方法

  [_output setRectOfInterest:CGRectMake()];

如果你感到疑惑那么可以看一下我写的这篇文章,里面有详细研究。

iOS 原生二维码扫描(可限制扫描区域)

生成二维码图片

生成二维码和扫描二维码图片就比较简单了,自己也写了个工具类来处理,这里直接贴出来代码,后面也会有代码可以下载

在这里借鉴的有别人的文章,想看原文点这里

首先LCQrcodeUtil.h中
/**
 *  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;
LCQrcodeUtil.m中
#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, G, B;

    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
   #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
#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
#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;
}

解析二维码图片

还是以源码的形式贴出来
这里也有借鉴别人的代码,点这里 查看原文

首先LCQrcodeUtil.h中
/**
 *  读取图片中二维码信息
 *
 *  @param image 图片
 *
 *  @return 二维码内容
 */
+(NSString *)readQRCodeFromImage:(UIImage *)image;
LCQrcodeUtil.m中
#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;
}

}

都是直接封装成类方法调用,这个类我也已经上传到Git,不想CV的可以到git中下载,地址:
https://github.com/liutongchao/LCQRCodeUtil

有问题欢迎指正以及互相探讨 – LC.West



相关标签: 二维码