彩票走势图

Dynamic Web TWAIN是一个专为Web应用程序设计的TWAIN扫描识别控件。你只需在TWAIN接口写几行代码，就可以用兼容TWAIN的扫描仪扫描文档或从数码相机/采集卡中获取图像。然后用户可以编辑图像并将图像保存为多种格式，用户可保存图像到远程数据库或者SharePoint。该TWAIN控件还支持上传和处理本地图像。

本文汇集了一些Dynamic Web TWAIN编程方面的常见问题，并且针对这些问题进行了回答，感兴趣的朋友快来了解一下吧~

点击下载Dynamic Web TWAIN正式版

将Dynamsoft Barcode SDK的C / C ++ API与JavaScript绑定

让我们开始使用Node.js条码C / C ++插件。
为了支持OpenCV Mat，我创建了一个新的API encodingBufferAsync（）。C / C ++代码如下：

void DecodeBufferAsync(const FunctionCallbackInfo& args) {
    if (!createDBR()) {return;}
    Isolate* isolate = Isolate::GetCurrent();
    Local context = isolate->GetCurrentContext();
 
    // get arguments
    unsigned char* buffer = (unsigned char*) node::Buffer::Data(args[0]); // file stream
    int width = args[1]->Int32Value(context).ToChecked();   // image width
    int height = args[2]->Int32Value(context).ToChecked();  // image height
    int stride = args[3]->Int32Value(context).ToChecked(); // stride
    int iFormat = args[4]->Int32Value(context).ToChecked(); // barcode types
    Local cb = Local::Cast(args[5]); // javascript callback function
    String::Utf8Value templateName(isolate, args[6]); // template name
    char *pTemplateName = *templateName;
 
    // initialize BarcodeWorker
    BarcodeWorker *worker = new BarcodeWorker;
    worker->request.data = worker;
    worker->callback.Reset(isolate, cb);
    worker->iFormat = iFormat;
    worker->pResults = NULL;
    worker->buffer = buffer;
    worker->width = width;
    worker->height = height;
    worker->bufferType = RGB_BUFFER;
    worker->stride = stride;
     
    if (hasTemplate(pTemplateName)) {
        // Load the template.
        char szErrorMsg[256];
        DBR_InitRuntimeSettingsWithString(hBarcode, pTemplateName, CM_OVERWRITE, szErrorMsg, 256);
        worker->useTemplate = true;
    }
    else {
        worker->useTemplate = false;
    }
 
    uv_queue_work(uv_default_loop(), &worker->request, (uv_work_cb)DetectionWorking, (uv_after_work_cb)DetectionDone);
}

const vCap = new cv.VideoCapture(0);
var img = vCap.read();
dbr.decodeBufferAsync(img.getData(), img.cols, img.rows, img.step, barcodeTypes, function (err, msg) {
        results = msg
 
    }, "");

'copies': [
                        {
                            'destination': '/usr/local/lib/',
                            'files': [
                                './platforms/macos/libDynamsoftBarcodeReader.dylib'
                            ]
                        }
                    ]

如果要将库文件和dbr.node保留在同一文件夹中，则可以手动更改库路径：

cd build/Release
install_name_tool -change /usr/local/lib/libDynamsoftBarcodeReader.dylib @loader_path/libDynamsoftBarcodeReader.dylib dbr.node

npm install -g node-gyp 
npm install barcode4nodejs

桌面

基本上，我们可以使用无限循环来捕获摄像头帧并将其显示在窗口中：

const cv = require('opencv4nodejs');
const vCap = new cv.VideoCapture(0);
const delay = 10;
while (true) {
  let frame = vCap.read();
  if (frame.empty) {
    vCap.reset();
    frame = vCap.read();
  }
  
  cv.imshow('OpenCV Node.js', frame);
  const key = cv.waitKey(delay); // Press ESC to quit
  if (key == 27) {break;}
}

const dbr = require('barcode4nodejs');
const cv = require('opencv4nodejs');
dbr.initLicense("LICENSE-KEY")
barcodeTypes = dbr.barcodeTypes
const vCap = new cv.VideoCapture(0);
const drawParams = { color: new cv.Vec(0, 255, 0), thickness: 2 }
const fontFace = cv.FONT_HERSHEY_SIMPLEX;
const fontScale = 0.5;
const textColor = new cv.Vec(255, 0, 0);
const thickness = 2;
 
results = null;
 
function getframe() {
    let img = vCap.read();
     
 
    dbr.decodeBufferAsync(img.getData(), img.cols, img.rows, img.step, barcodeTypes, function (err, msg) {
        results = msg
 
    }, "", 1);
     
 
    cv.imshow('Webcam', img);
    const key = cv.waitKey(10); // Press ESC to quit
    if (key != 27) {
        setTimeout(getframe, 30);
    }
 
}
 
getframe()

if (results != null) {
        for (index in results) {
            let result = results[index];
 
            let upperLeft = new cv.Point(result.x1, result.y1)
            let bottomLeft = new cv.Point(result.x2, result.y2)
            let upperRight = new cv.Point(result.x3, result.y3)
            let bottomRight = new cv.Point(result.x4, result.y4)
 
            img.drawLine(
                upperLeft,
                bottomLeft,
                drawParams
            )
            img.drawLine(
                bottomLeft,
                upperRight,
                drawParams
            )
 
            img.drawLine(
                upperRight,
                bottomRight,
                drawParams
            )
            img.drawLine(
                bottomRight,
                upperLeft,
                drawParams
            )
 
            img.putText(result.value, new cv.Point(result.x1, result.y1 + 10), fontFace, fontScale, textColor, thickness);
        }
 
    }

function capture() {
    var frame = wCap.read()
    if (frame.empty) {
        wCap.reset();
        frame = wCap.read();
    }
 
    dbr.decodeBufferAsync(frame.getData(), frame.cols, frame.rows, frame.step, barcodeTypes, function (err, msg) {
        // console.log(results)
        results = msg
 
    }, "", 1);
 
    if (results != null) {
        for (index in results) {
            let result = results[index];
 
            let upperLeft = new cv.Point(result.x1, result.y1)
            let bottomLeft = new cv.Point(result.x2, result.y2)
            let upperRight = new cv.Point(result.x3, result.y3)
            let bottomRight = new cv.Point(result.x4, result.y4)
 
            frame.drawLine(
                upperLeft,
                bottomLeft,
                drawParams
            )
            frame.drawLine(
                bottomLeft,
                upperRight,
                drawParams
            )
 
            frame.drawLine(
                upperRight,
                bottomRight,
                drawParams
            )
            frame.drawLine(
                bottomRight,
                upperLeft,
                drawParams
            )
 
            frame.putText(result.value, new cv.Point(result.x1, result.y1 + 10), fontFace, fontScale, textColor, thickness);
        }
 
 
    }
 
    img = cv.imencode('.jpg', frame);
    setTimeout(capture, 30);
}
 
capture();

Dynamic Web TWAIN的常见问答到这里就结束了，对相关问答感兴趣的朋友可以点击下方链接查看！

相关内容推荐：

Dynamic Web TWAIN常见问题（一）：如何选择使用哪个版本？
Dynamic Web TWAIN常见问题（二）：相比其他的TWAIN SDK，主要优势是什么？
Dynamic Web TWAIN常见问题（三）：Dynamic Web TWAIN将使用哪些操作系统？
Dynamic Web TWAIN常见问题（四）：编程问题-没有用户界面怎么工作？
Dynamic Web TWAIN常见问题（五）：编程问题-如何分别设置水平和垂直分辨率？

Dynamic Web TWAIN常见问题（六）：编程问题-如何使用SSL？

Dynamic Web TWAIN常见问题（七）：编程问题 - 如何进行双面扫描？

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