VintaSoft Twain .NET SDK 15.2: Руководство для .NET разработчика
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    Как сохранить eSCL отсканированное изображение в JPEG файл?
    В этом разделе
    Устройство eSCL может вернуть отсканированное изображение как сырое изображение. SDK берет полученное сырое изображение и создает объект EsclAcquiredImage. Отсканированное изображение, представленное объектом EsclAcquiredImage, можно сохранить в JPEG файл.
    Вот пример, демонстрирующий, как получить сырое изображение от eSCL сканера изображений и сохранить его в файл JPEG с помощью JPEG энкодера:
    /// <summary>
    /// Acquires image from eSCL device and saves image to a JPEG file.
    /// </summary>
    public void AcquireImageFromEsclDeviceAndSaveImageToJpegFile()
    {
        // create eSCL device manager
        using (Vintasoft.EsclImageScanning.EsclDeviceManager deviceManager = new Vintasoft.EsclImageScanning.EsclDeviceManager())
        {
            // open eSCL device manager
            deviceManager.Open();
    
            System.DateTime startTime = System.DateTime.Now;
            // while eSCL devices are not found
            while (deviceManager.Devices.Count == 0 && System.DateTime.Now.Subtract(startTime).Microseconds < 5000)
            {
                System.Threading.Thread.Sleep(10);
            }
            // get count of eSCL devices
            int deviceCount = deviceManager.Devices.Count;
            if (deviceCount == 0)
            {
                System.Console.WriteLine("Devices are not found.");
                return;
            }
    
            // select the first eSCL device
            Vintasoft.EsclImageScanning.EsclDevice device = deviceManager.Devices[0];
    
            // open eSCL device
            device.Open();
    
            Vintasoft.EsclImageScanning.EsclAcquiredImage acquiredImage = null;
            do
            {
                try
                {
                    // acquire image from eSCL device
                    acquiredImage = device.AcquireImageSync();
                    // if image is received
                    if (acquiredImage != null)
                    {
                        System.Console.WriteLine("Image is acquired.");
    
                        // create JPEG encoder settings
                        Vintasoft.EsclImageScanning.ImageEncoders.EsclJpegEncoderSettings jpegEncoderSettings =
                            new Vintasoft.EsclImageScanning.ImageEncoders.EsclJpegEncoderSettings();
                        // specify quality for JPEG image
                        jpegEncoderSettings.JpegQuality = 70;
    
                        // process acquired image
                        acquiredImage.Save("test.jpg", jpegEncoderSettings);
                    }
                    // if image is not received
                    else
                    {
                        System.Console.WriteLine("Scan is completed.");
                        break;
                    }
                }
                catch (System.Exception ex)
                {
                    System.Console.WriteLine(string.Format("Scan is failed: {0}", ex.Message));
                    break;
                }
            }
            // while image is acquired
            while (acquiredImage != null);
    
            // close eSCL device
            device.Close();
    
            // close eSCL device manager
            deviceManager.Close();
        }
    
        System.Console.ReadLine();
    }
    
    ''' <summary>
    ''' Acquires image from eSCL device and saves image to a JPEG file.
    ''' </summary>
    Public Sub AcquireImageFromEsclDeviceAndSaveImageToJpegFile()
        ' create eSCL device manager
        Using deviceManager As New Vintasoft.EsclImageScanning.EsclDeviceManager()
            ' open eSCL device manager
            deviceManager.Open()
    
            Dim startTime As System.DateTime = System.DateTime.Now
            ' while eSCL devices are not found
            While deviceManager.Devices.Count = 0 AndAlso System.DateTime.Now.Subtract(startTime).Microseconds < 5000
                System.Threading.Thread.Sleep(10)
            End While
            ' get count of eSCL devices
            Dim deviceCount As Integer = deviceManager.Devices.Count
            If deviceCount = 0 Then
                System.Console.WriteLine("Devices are not found.")
                Return
            End If
    
            ' select the first eSCL device
            Dim device As Vintasoft.EsclImageScanning.EsclDevice = deviceManager.Devices(0)
    
            ' open eSCL device
            device.Open()
    
            Dim acquiredImage As Vintasoft.EsclImageScanning.EsclAcquiredImage = Nothing
            Do
                Try
                    ' acquire image from eSCL device
                    acquiredImage = device.AcquireImageSync()
                    ' if image is received
                    If acquiredImage IsNot Nothing Then
                        System.Console.WriteLine("Image is acquired.")
    
                        ' create JPEG encoder settings
                        Dim jpegEncoderSettings As New Vintasoft.EsclImageScanning.ImageEncoders.EsclJpegEncoderSettings()
                        ' specify quality for JPEG image
                        jpegEncoderSettings.JpegQuality = 70
    
                        ' process acquired image
                        acquiredImage.Save("test.jpg", jpegEncoderSettings)
                    Else
                        ' if image is not received
                        System.Console.WriteLine("Scan is completed.")
                        Exit Try
                    End If
                Catch ex As System.Exception
                    System.Console.WriteLine(String.Format("Scan is failed: {0}", ex.Message))
                    Exit Try
                End Try
                ' while image is acquired
            Loop While acquiredImage IsNot Nothing
    
            ' close eSCL device
            device.Close()
    
            ' close eSCL device manager
            deviceManager.Close()
        End Using
    
        System.Console.ReadLine()
    End Sub
    


    Также устройство eSCL может получать изображение в виде JPEG-потока, т. е. устройство eSCL сканирует изображение, кодирует отсканированное изображение в формат JPEG и возвращает JPEG-поток.
    Вот пример, демонстрирующий, как получить изображение в виде JPEG-потока от eSCL сканера изображений и сохранить полученный JPEG-поток в файл:
    /// <summary>
    /// Synchronously acquire images as JPEG stream from eSCL device.
    /// </summary>
    public void SynchronouslyAcquireImagesAsJpegStreamFromEsclDevice()
    {
        // create eSCL device manager
        using (Vintasoft.EsclImageScanning.EsclDeviceManager deviceManager = new Vintasoft.EsclImageScanning.EsclDeviceManager())
        {
            // open eSCL device manager
            deviceManager.Open();
    
            System.DateTime startTime = System.DateTime.Now;
            // while eSCL devices are not found
            while (deviceManager.Devices.Count == 0 && System.DateTime.Now.Subtract(startTime).Microseconds < 5000)
            {
                System.Threading.Thread.Sleep(10);
            }
            // get count of eSCL devices
            int deviceCount = deviceManager.Devices.Count;
            if (deviceCount == 0)
            {
                System.Console.WriteLine("Devices are not found.");
                return;
            }
    
            // select the first eSCL device
            Vintasoft.EsclImageScanning.EsclDevice device = deviceManager.Devices[0];
    
            // open eSCL device
            device.Open();
    
            int imageIndex = 0;
            byte[] acquiredImageBytes = null;
            do
            {
                try
                {
                    // acquire image as JPEG stream from eSCL device
                    acquiredImageBytes = device.AcquireImageSyncAsFileStream(Vintasoft.EsclImageScanning.EsclScanDocumentFormat.JPEG);
                    // if image is received
                    if (acquiredImageBytes != null)
                    {
                        imageIndex++;
                        string filename = string.Format("scannedImage-{0}.jpg", imageIndex);
                        if (System.IO.File.Exists(filename))
                            System.IO.File.Delete(filename);
    
                        System.IO.File.WriteAllBytes(filename, acquiredImageBytes);
    
                        System.Console.WriteLine(string.Format("Acquired image is saved to a file '{0}'.", filename));
                    }
                    // if image is not received
                    else
                    {
                        System.Console.WriteLine("Scan is completed.");
                        break;
                    }
                }
                catch (System.Exception ex)
                {
                    System.Console.WriteLine(string.Format("Scan is failed: {0}", ex.Message));
                    break;
                }
            }
            // while image is acquired
            while (acquiredImageBytes != null);
    
            // close eSCL device
            device.Close();
    
            // close eSCL device manager
            deviceManager.Close();
        }
    
        System.Console.ReadLine();
    }
    
    ''' <summary>
    ''' Synchronously acquire images as JPEG stream from eSCL device.
    ''' </summary>
    Public Sub SynchronouslyAcquireImagesAsJpegStreamFromEsclDevice()
        ' create eSCL device manager
        Using deviceManager As New Vintasoft.EsclImageScanning.EsclDeviceManager()
            ' open eSCL device manager
            deviceManager.Open()
    
            Dim startTime As System.DateTime = System.DateTime.Now
            ' while eSCL devices are not found
            While deviceManager.Devices.Count = 0 AndAlso System.DateTime.Now.Subtract(startTime).Microseconds < 5000
                System.Threading.Thread.Sleep(10)
            End While
            ' get count of eSCL devices
            Dim deviceCount As Integer = deviceManager.Devices.Count
            If deviceCount = 0 Then
                System.Console.WriteLine("Devices are not found.")
                Return
            End If
    
            ' select the first eSCL device
            Dim device As Vintasoft.EsclImageScanning.EsclDevice = deviceManager.Devices(0)
    
            ' open eSCL device
            device.Open()
    
            Dim imageIndex As Integer = 0
            Dim acquiredImageBytes As Byte() = Nothing
            Do
                Try
                    ' acquire image as JPEG stream from eSCL device
                    acquiredImageBytes = device.AcquireImageSyncAsFileStream(Vintasoft.EsclImageScanning.EsclScanDocumentFormat.JPEG)
                    ' if image is received
                    If acquiredImageBytes IsNot Nothing Then
                        imageIndex += 1
                        Dim filename As String = String.Format("scannedImage-{0}.jpg", imageIndex)
                        If System.IO.File.Exists(filename) Then
                            System.IO.File.Delete(filename)
                        End If
    
                        System.IO.File.WriteAllBytes(filename, acquiredImageBytes)
    
                        System.Console.WriteLine(String.Format("Acquired image is saved to a file '{0}'.", filename))
                    Else
                        ' if image is not received
                        System.Console.WriteLine("Scan is completed.")
                        Exit Try
                    End If
                Catch ex As System.Exception
                    System.Console.WriteLine(String.Format("Scan is failed: {0}", ex.Message))
                    Exit Try
                End Try
                ' while image is acquired
            Loop While acquiredImageBytes IsNot Nothing
    
            ' close eSCL device
            device.Close()
    
            ' close eSCL device manager
            deviceManager.Close()
        End Using
    
        System.Console.ReadLine()
    End Sub