How to acquire the top part of page from TWAIN/WIA/SANE/eSCL image scanner?

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If you want to set the scan area for TWAIN/WIA/SANE/eSCL image scanner, please use the WebTwainDeviceJS.setImageLayout function.

Also TWAIN image scanner allows to set the scan area using the WebTwainDeviceJS.setCapability function.

Here is JavaScript code that demonstrates how to use WebDeviceJS.setImageLayout function for acquiring image area from TWAIN/WIA/SANE/eSCL image scanner:

JavaScript

// acquire top part of page from TWAIN/WIA/SANE/eSCL image scanner
__acquireTopPartOfPageFromTwainScanner();



/**
 * Acquires top part of page from TWAIN/WIA/SANE/eSCL image scanner.
 */
function __acquireTopPartOfPageFromTwainScanner() {
    // 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 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);

        // set the inches as unit of measure
        device.set_UnitOfMeasure(new Vintasoft.Twain.WebTwainUnitOfMeasureEnumJS("Inches"));
        // get current image layout
        let imageLayout: Vintasoft.Twain.WebTwainImageLayoutJS = device.getImageLayout();
        // set the image layout (get only the top half of the page)
        device.setImageLayout(0, 0, imageLayout.get_Width(), imageLayout.get_Height() / 2); 

        // 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 image collection
                    acquiredImages.add(acquiredImage);

                    // get image as Base64 string
                    var bitmapAsBase64String = acquiredImage.getAsBase64String();
                    // update image preview
                    var previewImageElement = document.getElementById('previewImage');
                    previewImageElement.src = bitmapAsBase64String;

                    // 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 use WebDeviceJS.setImageLayout function for acquiring image area from TWAIN/WIA/SANE/eSCL image scanner:

TYPESCRIPT

import { Component } from '@angular/core';

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

  ngOnInit() {
    // acquire top part of page from TWAIN/WIA/SANE/eSCL image scanner
    this.__acquireTopPartOfPageFromTwainScanner();
  }


  /**
   * Acquires top part of page from TWAIN/WIA/SANE/eSCL image scanner.
   */
  __acquireTopPartOfPageFromTwainScanner() {
    // 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 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 device: Vintasoft.Twain.WebTwainDeviceJS = null;
    try {
      // get the default TWAIN/WIA/SANE/eSCL device
      device = deviceManager.get_DefaultDevice();

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

      // set the inches as unit of measure
      device.set_UnitOfMeasure(new Vintasoft.Twain.WebTwainUnitOfMeasureEnumJS("Inches"));
      // get current image layout
      let imageLayout: Vintasoft.Twain.WebTwainImageLayoutJS = device.getImageLayout();
      // set the image layout (get only the top half of the page)
      device.setImageLayout(0, 0, imageLayout.get_Width(), imageLayout.get_Height() / 2); 

      // 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 = device.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 image collection
            acquiredImages.add(acquiredImage);

            // get image as Base64 string
            let bitmapAsBase64String: string = acquiredImage.getAsBase64String();
            // update image preview
            let previewImageElement: HTMLImageElement = document.getElementById('previewImage') as HTMLImageElement;
            previewImageElement.src = bitmapAsBase64String;

            // 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 use WebDeviceJS.setCapability function for acquiring image area from TWAIN/SANE image scanner:

JavaScript

// acquire top part of page from TWAIN image scanner
__acquireTopPartOfPageFromTwainScanner();



/**
 * Acquires top part of page from TWAIN image scanner.
 */
function __acquireTopPartOfPageFromTwainScanner() {
    // 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 devices
    var twainService = new Vintasoft.Shared.WebServiceControllerJS(serviceUrl);

    // TWAIN 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 device
        device = deviceManager.get_DefaultDevice();

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

        // set the inches as unit of measure
        device.set_UnitOfMeasure(new Vintasoft.Twain.WebTwainUnitOfMeasureEnumJS("Inches"));
        // set the image layout rectangle as value of IFrames capability
        device.setCapability(new Vintasoft.Twain.WebTwainDeviceCapabilityIdEnumJS("IFrames"), new Vintasoft.Twain.WebTwainFrameJS(0, 0, 2, 2));

        // a collection that stores images, which are acquired from TWAIN 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 image collection
                    acquiredImages.add(acquiredImage);

                    // get image as Base64 string
                    var bitmapAsBase64String = acquiredImage.getAsBase64String();
                    // update image preview
                    var previewImageElement = document.getElementById('previewImage');
                    previewImageElement.src = bitmapAsBase64String;

                    // 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 use WebDeviceJS.setCapability function for acquiring image area from TWAIN/SANE image scanner:

TYPESCRIPT

import { Component } from '@angular/core';

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

  ngOnInit() {
    // acquire top part of page from TWAIN image scanner
    this.__acquireTopPartOfPageFromTwainScanner();
  }


  /**
   * Acquires top part of page from TWAIN image scanner.
   */
  __acquireTopPartOfPageFromTwainScanner() {
    // 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 devices
    let twainService: Vintasoft.Shared.WebServiceControllerJS = new Vintasoft.Shared.WebServiceControllerJS(serviceUrl);

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

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

      // set the inches as unit of measure
      device.set_UnitOfMeasure(new Vintasoft.Twain.WebTwainUnitOfMeasureEnumJS("Inches"));
      // set the image layout rectangle as value of IFrames capability
      device.setCapability(new Vintasoft.Twain.WebTwainDeviceCapabilityIdEnumJS("IFrames"), new Vintasoft.Twain.WebTwainFrameJS(0, 0, 2, 2));

      // a collection that stores images, which are acquired from TWAIN 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 = device.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 image collection
            acquiredImages.add(acquiredImage);

            // get image as Base64 string
            let bitmapAsBase64String: string = acquiredImage.getAsBase64String();
            // update image preview
            let previewImageElement: HTMLImageElement = document.getElementById('previewImage') as HTMLImageElement;
            previewImageElement.src = bitmapAsBase64String;

            // 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();
    }
  }

}

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