How to scan negatives using TWAIN image scanner?
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Scan negatives using TWAIN image scanner
If you want to scan negatives using TWAIN image scanner, you should pass the WebTwainLightPathEnumJS.Transmissive value to the the
WebTwainDeviceJS.set_LightPath function.
Here is JavaScript code that demonstrates how to scan negatives using TWAIN image scanner:
// scan negatives using TWAIN image scanner
__scanNegativesUsingTwainScanner();
/**
* Scans negatives using TWAIN image scanner.
*/
function __scanNegativesUsingTwainScanner() {
// 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/SANE/eSCL devices
var twainService = new Vintasoft.Shared.WebServiceControllerJS(serviceUrl);
// TWAIN/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 device
device = deviceManager.get_DefaultDevice();
// open device without UI
device.open(false);
// specify that color images must be acquired from TWAIN image scanner
device.set_PixelType(new Vintasoft.Twain.WebTwainPixelTypeEnumJS("RGB"));
// specify that negatives must be acquired from TWAIN image scanner
device.set_LightPath(new Vintasoft.Twain.WebTwainLightPathEnumJS("Transmissive"));
// a collection that stores images, which are acquired from TWAIN/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 scan negatives using TWAIN image scanner:
import { Component } from '@angular/core';
@Component({
selector: 'twain-scanning-demo',
templateUrl: './twain-scanning-demo.component.html'
})
export class TwainScanningDemoComponent {
ngOnInit() {
// scan negatives using TWAIN image scanner
__scanNegativesUsingTwainScanner();
}
/**
* Scans negatives using TWAIN image scanner.
*/
__scanNegativesUsingTwainScanner() {
// 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/SANE/eSCL devices
let twainService: Vintasoft.Shared.WebServiceControllerJS = new Vintasoft.Shared.WebServiceControllerJS(serviceUrl);
// TWAIN/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 device
twainDevice = deviceManager.get_DefaultDevice();
// open device without UI
twainDevice.open(false);
// specify that color images must be acquired from TWAIN image scanner
twainDevice.set_PixelType(new Vintasoft.Twain.WebTwainPixelTypeEnumJS("RGB"));
// specify that negatives must be acquired from TWAIN image scanner
twainDevice.set_LightPath(new Vintasoft.Twain.WebTwainLightPathEnumJS("Transmissive"));
// a collection that stores images, which are acquired from TWAIN/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 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 (twainDevice != null) {
// close the device
twainDevice.close();
}
// close the device manager
deviceManager.close();
}
}
}
Scan negatives using SANE image scanner
If you want to scan negatives using SANE image scanner, you should set the scan mode allowing to scan negatives, for example, HP scanners have "Negative" scan mode. The scan mode of SANE image scanner can be set using the
WebTwainDeviceJS.set_SaneScanMode function.