VintaSoft Twain .NET SDK 15.4: Documentation for Web developer
In This Topic
Synchronously acquire images from TWAIN/WIA/SANE/eSCL image scanner
In This Topic
VintaSoft Web Twain service allows to acquire images from TWAIN/WIA/SANE/eSCL image scanner synchronously (in a modal loop).

Here are steps, which should be done for synchronous acquisition of images from TWAIN/WIA/SANE/eSCL device:
  1. Open TWAIN/WIA/SANE/eSCL device manager.
  2. Select TWAIN/WIA/SANE/eSCL device.
  3. Open TWAIN/WIA/SANE/eSCL device.
  4. Set the TWAIN/WIA/SANE/eSCL device settings.
  5. Start the synchronous acquisition of images from TWAIN/WIA/SANE/eSCL device by calling WebTwainDeviceJS.acquireModalSync function.
  6. Retrieve acquired images one by one while the WebTwainDeviceJS.acquireModalSync function returns WebTwainAcquireModalStateEnumJS.ImageAcquired.
  7. Break loop if WebTwainDeviceJS.acquireModalSync function returns WebTwainAcquireModalStateEnumJS.None.

Here is JavaScript code that demonstrates how to synchronously acquire images from TWAIN/WIA/SANE/eSCL image scanner and save acquired images into PDF document:
// synchronously acquire images from TWAIN/WIA/SANE/eSCL image scanner and saves acquired images to PDF file
__synchronouslyAcquireImagesFromTwainScannerAndSaveToPdfFile();



/**
 * Synchronously acquires images from TWAIN/WIA/SANE/eSCL image scanner and saves acquired images to PDF file.
 */
function __synchronouslyAcquireImagesFromTwainScannerAndSaveToPdfFile() {
    // register the evaluation version of VintaSoft Web TWAIN service
    // please read how to get evaluation license in documentation: https://www.vintasoft.com/docs/vstwain-dotnet-web/Licensing-Twain_Web-Evaluation.html
    Vintasoft.Twain.WebTwainGlobalSettingsJS.register('REG_USER', 'REG_URL', 'REG_CODE', 'EXPIRATION_DATE');

    // URL to the VintaSoft Web TWAIN service
    var serviceUrl = 'https://localhost:25329/api/VintasoftTwainApi';
    // a Web API controller that allows to work with TWAIN/WIA/SANE/eSCL/eSCL devices
    var twainService = new Vintasoft.Shared.WebServiceControllerJS(serviceUrl);

    // TWAIN/WIA/SANE/eSCL device manager
    var deviceManager = new Vintasoft.Twain.WebTwainDeviceManagerJS(twainService);

    // the default settings of device manager
    var deviceManagerInitSetting = new Vintasoft.Twain.WebTwainDeviceManagerInitSettingsJS();

    var device = null;
    try {
        // open device manager
        deviceManager.open(deviceManagerInitSetting);

        // get the default TWAIN/WIA/SANE/eSCL device
        device = deviceManager.get_DefaultDevice();

        // open device without UI
        device.open(false);

        // a collection that stores images, which are acquired from TWAIN/WIA/SANE/eSCL devices and stored in memory of VintaSoft Web TWAIN service
        var acquiredImages = new Vintasoft.Twain.WebAcquiredImageCollectionJS(deviceManager);

        var acquireModalState;
        do {
            // do one step of modal image acquisition process
            var acquireModalResult = device.acquireModalSync();
            // get state of image acquisition
            acquireModalState = acquireModalResult.get_AcquireModalState().valueOf();

            switch (acquireModalState) {
                case 2:   // image is acquired
                    // get acquired image
                    var acquiredImage = acquireModalResult.get_AcquiredImage();
                    // add acquired image to the collection of acquired images
                    acquiredImages.add(acquiredImage);

                    // save acquired image to "result.pdf" file
                    acquiredImages.saveImages("d:\\result.pdf", false, [ acquiredImage.get_Id() ]);

                    // clear image collection (delete images from memory of VintaSoft Web TWAIN service) because image is not necessary anymore
                    acquiredImages.clear();
                    break;

                case 4:   // image scan is failed
                    alert(acquireModalResult.get_ErrorMessage());
                    break;

                case 9:   // image scan is finished
                    break;
            }
        }
        while (acquireModalState !== 0);
    }
    catch (ex) {
        alert(ex);
    }
    finally {
        if (device != null) {
            // close the device
            device.close();
        }
        // close the device manager
        deviceManager.close();
    }
}



Here is TypeScript code that demonstrates how to synchronously acquire images from TWAIN/WIA/SANE/eSCL image scanner and save acquired images into PDF document:
import { Component } from '@angular/core';

@Component({
  selector: 'twain-scanning-demo',
  templateUrl: './twain-scanning-demo.component.html'
})
export class TwainScanningDemoComponent {

  ngOnInit() {
    // synchronously acquire images from TWAIN/WIA/SANE/eSCL image scanner and saves acquired images to PDF file
    this.__synchronouslyAcquireImagesFromTwainScannerAndSaveToPdfFile();
  }


  /**
   * Synchronously acquires images from TWAIN/WIA/SANE/eSCL image scanner and saves acquired images to PDF file.
   */
  __synchronouslyAcquireImagesFromTwainScannerAndSaveToPdfFile() {
    // register the evaluation version of VintaSoft Web TWAIN service
    // please read how to get evaluation license in documentation: https://www.vintasoft.com/docs/vstwain-dotnet-web/Licensing-Twain_Web-Evaluation.html
    Vintasoft.Twain.WebTwainGlobalSettingsJS.register('REG_USER', 'REG_URL', 'REG_CODE', 'EXPIRATION_DATE');

    // URL to the VintaSoft Web TWAIN service
    let serviceUrl: string = 'https://localhost:25329/api/VintasoftTwainApi';
    // a Web API controller that allows to work with TWAIN/WIA/SANE/eSCL/eSCL devices
    let twainService: Vintasoft.Shared.WebServiceControllerJS = new Vintasoft.Shared.WebServiceControllerJS(serviceUrl);

    // TWAIN/WIA/SANE/eSCL device manager
    let deviceManager: Vintasoft.Twain.WebTwainDeviceManagerJS = new Vintasoft.Twain.WebTwainDeviceManagerJS(twainService);

    // the default settings of device manager
    let deviceManagerInitSetting: Vintasoft.Twain.WebTwainDeviceManagerInitSettingsJS = new Vintasoft.Twain.WebTwainDeviceManagerInitSettingsJS();

    try {
      // open device manager
      deviceManager.open(deviceManagerInitSetting);
    }
    catch (ex) {
      alert(ex);
      return;
    }

    let twainDevice: Vintasoft.Twain.WebTwainDeviceJS = null;
    try {
      // get the default TWAIN/WIA/SANE/eSCL device
      twainDevice = deviceManager.get_DefaultDevice();

      // open device without UI
      twainDevice.open(false);

      // a collection that stores images, which are acquired from TWAIN/WIA/SANE/eSCL devices and stored in memory of VintaSoft Web TWAIN service
      let acquiredImages: Vintasoft.Twain.WebAcquiredImageCollectionJS = new Vintasoft.Twain.WebAcquiredImageCollectionJS(deviceManager);

      let acquireModalState: number;
      do {
        // do one step of modal image acquisition process
        let acquireModalResult: Vintasoft.Twain.WebTwainDeviceAcquireModalResultJS = twainDevice.acquireModalSync();
        // get state of image acquisition
        acquireModalState = acquireModalResult.get_AcquireModalState().valueOf() as number;

        switch (acquireModalState) {
          case 2:   // image is acquired
            // get acquired image
            let acquiredImage: Vintasoft.Twain.WebAcquiredImageJS = acquireModalResult.get_AcquiredImage();
            // add acquired image to the collection of acquired images
            acquiredImages.add(acquiredImage);

            // save acquired image to "result.pdf" file
            acquiredImages.saveImages("d:\\result.pdf", false, [acquiredImage.get_Id()]);

            // clear image collection (delete images from memory of VintaSoft Web TWAIN service) because image is not necessary anymore
            acquiredImages.clear();
            break;

          case 4:   // image scan is failed
            alert(acquireModalResult.get_ErrorMessage());
            break;

          case 9:   // image scan is finished
            break;
        }
      }
      while (acquireModalState !== 0);
    }
    catch (ex) {
      alert(ex);
    }
    finally {
      if (twainDevice != null) {
        // close the device
        twainDevice.close();
      }
      // close the device manager
      deviceManager.close();
    }
  }

}