VintaSoft Twain .NET SDK 15.1: Documentation for Web developer
In This Topic
    How to get information about capabilities/options of TWAIN/SANE device?
    In This Topic
    TWAIN standard defines many standard capabilities (XferCount, IPixelType, DoubleFeedDetection, IContrast, IRotation, etc), which can be supported by TWAIN device. Also TWAIN device can provide custom capabilities, which are defined by scanner manufacturer.

    If you want to get a list of capabilities, which are supported by TWAIN device, please use the WebTwainDeviceJS.getSupportedCapabilities function.

    If you want to get current value of TWAIN device capability, please use the WebTwainCapabilityInfoJS.get_CurrentValue function.
    If you want to get the default value of TWAIN device capability, please use the WebTwainCapabilityInfoJS.get_DefaultValue function.
    If you want to get supported values of TWAIN device capability, please use the WebTwainCapabilityInfoJS.get_SupportedValues function.



    SANE API does not define standard options for SANE device, SANE API just defines rules, which allow to create self-describing options by device manufacturer.

    If you want to get a list of options, which are supported by SANE device, please use the WebTwainDeviceJS.getSupportedCapabilities function.

    If you want to get current value of SANE device option, please use the WebTwainCapabilityInfoJS.get_CurrentValue function.
    If you want to get supported values of SANE device option, please use the WebTwainCapabilityInfoJS.get_SupportedValues function.



    Here is JavaScript code that demonstrates how to get information about supported values of capability/option of TWAIN/SANE device:
    // get information about capability value from TWAIN/SANE scanner
    __getCapValueFromTwainScanner();
    
    
    
    /**
     * Returns information about capability value from TWAIN/SANE scanner.
     */
    function __getCapValueFromTwainScanner() {
        // 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 and SANE devices
        var twainService = new Vintasoft.Shared.WebServiceControllerJS(serviceUrl);
    
        // TWAIN/SANE 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/SANE device
            device = deviceManager.get_DefaultDevice();
    
            // open device without UI
            device.open(false);
    
            // if device is SANE device
            if (device.get_DeviceName().substring(0, 4) == "Sane") {
                // get "mode" option of SANE device
                var scanModeOption = device.getCapability("mode", new Vintasoft.Twain.WebTwainDeviceCapabilityUsageModeEnumJS("Get"));
                // if "mode" option is supported by SANE device
                if (scanModeOption != null) {
                    // output information about current scan mode
                    console.log("Current scan mode: " + scanModeOption.get_CurrentValue());
    
                    // get supported scan modes
                    var supportedScanModes = scanModeOption.get_SupportedValues();
                    var supportedScanModesAsArray = supportedScanModess.get_SupportedValuesAsArray();
                    var supportedScanModesString = "Supported scan modes: ";
                    // for each supported scan mode
                    for (var j = 0; j < supportedScanModesAsArray.length; j++) {
                        supportedScanModesString += supportedScanModesAsArray[j].toString() + ' ';
                    }
                    // output information about supported scan modes
                    console.log(supportedScanModesString);
                }
            }
            // if device is TWAIN device
            else {
                // get IPixelType capability of TWAIN device
                var pixelTypeCap = device.getCapability(
                    new Vintasoft.Twain.WebDeviceCapabilityIdEnumJS("IPixelType"),
                    new Vintasoft.Twain.WebTwainDeviceCapabilityUsageModeEnumJS("Get"));
                // if IPixelType capability is supported by TWAIN device
                if (pixelTypeCap != null) {
                    // output information about current pixel type
                    console.log("Current pixel type: " + pixelTypeCap.get_CurrentValue());
                    // output information about default pixel type
                    console.log("Default pixel type: " + pixelTypeCap.get_DefaultValue());
    
                    // get supported pixel types
                    var supportedPixelTypes = pixelTypeCap.get_SupportedValues();
                    var supportedPixelTypesAsArray = supportedPixelTypes.get_SupportedValuesAsArray();
                    var supportedPixelTypesString = "Supported pixel types: ";
                    // for each supported pixel type
                    for (var j = 0; j < supportedPixelTypesAsArray.length; j++) {
                        supportedPixelTypesString += supportedPixelTypesAsArray[j].toString() + ' ';
                    }
                    // output information about supported pixel types
                    console.log(supportedPixelTypesString);
                }
            }
    
            // a collection that stores images, which are acquired from TWAIN/SANE 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 get information about supported values of capability/option of TWAIN/SANE device:
    import { Component } from '@angular/core';
    
    @Component({
      selector: 'twain-scanning-demo',
      templateUrl: './twain-scanning-demo.component.html'
    })
    export class TwainScanningDemoComponent {
    
      ngOnInit() {
        // get information about capability value from TWAIN/SANE device
        this.__getCapValueFromTwainScanner();
      }
    
    
      /**
       * Returns information about capability value from TWAIN/SANE device.
       */
      __getCapValueFromTwainScanner() {
        // 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 and SANE devices
        let twainService: Vintasoft.Shared.WebServiceControllerJS = new Vintasoft.Shared.WebServiceControllerJS(serviceUrl);
    
        // TWAIN/SANE 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/SANE device
          device = deviceManager.get_DefaultDevice();
    
          // open device without UI
          device.open(false);
    
          // if device is SANE device
          if (device.get_DeviceName().substring(0, 4) == "Sane") {
            // get "mode" option of SANE device
            let scanModeOption: Vintasoft.Twain.WebTwainCapabilityInfoJS = device.getCapability(
              "mode",
              new Vintasoft.Twain.WebTwainDeviceCapabilityUsageModeEnumJS("Get"));
            // if "mode" option is supported by SANE device
            if (scanModeOption != null) {
              // output information about current scan mode
              console.log("Current scan mode: " + scanModeOption.get_CurrentValue());
    
              // get supported scan modes
              let supportedScanModes: Vintasoft.Twain.WebTwainCapabilitySupportedValuesJS = scanModeOption.get_SupportedValues();
              let supportedScanModesAsArray: object[] = supportedScanModes.get_SupportedValuesAsArray();
              let supportedScanModesString: string = "Supported scan modes: ";
              // for each supported scan mode
              for (let j: number = 0; j < supportedScanModesAsArray.length; j++) {
                supportedScanModesString += supportedScanModesAsArray[j].toString() + ' ';
              }
              // output information about supported scan modes
              console.log(supportedScanModesString);
            }
          }
          // if device is TWAIN device
          else {
            // get IPixelType capability of TWAIN device
            let pixelTypeCap: Vintasoft.Twain.WebTwainCapabilityInfoJS = device.getCapability(
              new Vintasoft.Twain.WebDeviceCapabilityIdEnumJS("IPixelType"),
              new Vintasoft.Twain.WebTwainDeviceCapabilityUsageModeEnumJS("Get"));
            // if IPixelType capability is supported by TWAIN scanner
            if (pixelTypeCap != null) {
              // output information about current pixel type
              console.log("Current pixel type: " + pixelTypeCap.get_CurrentValue());
              // output information about default pixel type
              console.log("Default pixel type: " + pixelTypeCap.get_DefaultValue());
    
              // get supported pixel types
              let supportedPixelTypes: Vintasoft.Twain.WebTwainCapabilitySupportedValuesJS = pixelTypeCap.get_SupportedValues();
              let supportedPixelTypesAsArray: object[] = supportedPixelTypes.get_SupportedValuesAsArray();
              let supportedPixelTypesString: string = "Supported pixel types: ";
              // for each supported pixel type
              for (let j: number = 0; j < supportedPixelTypesAsArray.length; j++) {
                supportedPixelTypesString += supportedPixelTypesAsArray[j].toString() + ' ';
              }
              // output information about supported pixel types
              console.log(supportedPixelTypesString);
            }
          }
    
          // a collection that stores images, which are acquired from TWAIN/SANE 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();
        }
      }
    
    }