Как сохранить TWAIN отсканированное изображение в JPEG файл?

В этом разделе

Вы можете получить изображение от TWAIN сканера и сохранить его как JPEG файл тремя способами:

1. С помощью JPEG кодека из SDK для режимов передачи Native или Memory

Этот метод работает с любым TWAIN сканером.
Изображение кодируется с помощью внутреннего кодека SDK.
Качество JPEG можно установить с помощью свойства Vintasoft.Twain.ImageEncoders.TwainJpegEncoderSettings.JpegQuality.
Изображение сохраняется в JPEG файл с помощью метода Vintasoft.Twain.AcquiredImage.Save.

Вот C#/VB.NET код, который демонстрирует, как отсканировать изображение и сохранить его как JPEG файл, используя JPEG кодек SDK:

/// <summary>
/// Synchronously acquires not compressed images from TWAIN device and saves images to JPEG files.
/// </summary>
static void AcquireNotCompressedImagesFromTwainDeviceAndSaveImagesToJpegFiles()
{
    // create the device manager
    using (Vintasoft.Twain.DeviceManager deviceManager = new Vintasoft.Twain.DeviceManager())
    {
        // open the device manager
        deviceManager.Open();

        // get reference to the default device
        Vintasoft.Twain.Device device = deviceManager.DefaultDevice;

        // specify that device UI must not be used
        device.ShowUI = false;

        // open the device
        device.Open();

        // specify that Memory transfer mode must be used
        device.TransferMode = Vintasoft.Twain.TransferMode.Memory;

        // acquire images from device
        Vintasoft.Twain.AcquireModalState acquireModalState = Vintasoft.Twain.AcquireModalState.None;
        do
        {
            acquireModalState = device.AcquireModal();
            switch (acquireModalState)
            {
                case Vintasoft.Twain.AcquireModalState.ImageAcquired:
                    // specify JPEG encoder settings
                    Vintasoft.Twain.ImageEncoders.TwainJpegEncoderSettings jpegEncoderSettings =
                        new Vintasoft.Twain.ImageEncoders.TwainJpegEncoderSettings();
                    jpegEncoderSettings.JpegQuality = 50;

                    // save acquired image to a disk, internal SDK encoder will be used
                    device.AcquiredImage.Save("test.jpg", jpegEncoderSettings);

                    // dispose acquired image
                    device.AcquiredImage.Dispose();
                    break;
            }
        }
        while (acquireModalState != Vintasoft.Twain.AcquireModalState.None);

        // close the device
        device.Close();

        // close the device manager
        deviceManager.Close();
    }
}

VB.NET

''' <summary>
''' Synchronously acquires not compressed images from TWAIN device and saves images to JPEG files.
''' </summary>
Private Shared Sub AcquireNotCompressedImagesFromTwainDeviceAndSaveImagesToJpegFiles()
    ' create the device manager
    Using deviceManager As New Vintasoft.Twain.DeviceManager()
        ' open the device manager
        deviceManager.Open()

        ' get reference to the default device
        Dim device As Vintasoft.Twain.Device = deviceManager.DefaultDevice

        ' specify that device UI must not be used
        device.ShowUI = False

        ' open the device
        device.Open()

        ' specify that Memory transfer mode must be used
        device.TransferMode = Vintasoft.Twain.TransferMode.Memory

        ' acquire images from device
        Dim acquireModalState As Vintasoft.Twain.AcquireModalState = Vintasoft.Twain.AcquireModalState.None
        Do
            acquireModalState = device.AcquireModal()
            Select Case acquireModalState
                Case Vintasoft.Twain.AcquireModalState.ImageAcquired
                    ' specify JPEG encoder settings
                    Dim jpegEncoderSettings As New Vintasoft.Twain.ImageEncoders.TwainJpegEncoderSettings()
                    jpegEncoderSettings.JpegQuality = 50

                    ' save acquired image to a disk, internal SDK encoder will be used
                    device.AcquiredImage.Save("test.jpg", jpegEncoderSettings)

                    ' dispose acquired image
                    device.AcquiredImage.Dispose()
                    Exit Select
            End Select
        Loop While acquireModalState <> Vintasoft.Twain.AcquireModalState.None

        ' close the device
        device.Close()

        ' close the device manager
        deviceManager.Close()
    End Using
End Sub

2. С помощью JPEG кодека TWAIN драйвера для режима передачи File

Драйвер TWAIN должен иметь встроенный кодек JPEG - вы можете проверить это с помощью метода Vintasoft.Twain.Device.GetSupportedImageFileFormats.
Драйвер TWAIN кодирует полученное изображение и сохраняет его непосредственно в файл на диск.
Сжатие JPEG можно установить с помощью свойства Vintasoft.Twain.Device.FileFormat.
Имя файла JPEG можно задать с помощью свойства Vintasoft.Twain.Device.FileName.
Качество файла JPEG можно установить с помощью свойства Vintasoft.Twain.Device.FileJpegQuality.

Вот C#/VB.NET код, который демонстрирует, как сохранить отсканированное изображение непосредственно на диск в виде файла JPEG:

/// <summary>
/// Starts synchronous acquisition of image from TWAIN device and specifies that acquired JPEG compressed images must be saved directly to JPEG files on disk.
/// </summary>
static void StartSynchronousTwainScanningAndSpecifyThatJpegCompressedImagesMustBeSavedDirectlyToJpegFiles()
{
    // create the device manager
    using (Vintasoft.Twain.DeviceManager deviceManager = new Vintasoft.Twain.DeviceManager())
    {
        // open the device manager
        deviceManager.Open();

        // get reference to the default device
        Vintasoft.Twain.Device device = deviceManager.DefaultDevice;

        // specify that device UI must not be used
        device.ShowUI = false;

        // open the device
        device.Open();

        // check if device driver can save image to disk as JPEG files
        Vintasoft.Twain.TwainImageFileFormat[] supportedImageFileFormats = device.GetSupportedImageFileFormats();
        bool isJpegFileFormatSupported = false;
        for (int i = 0; i < supportedImageFileFormats.Length; i++)
        {
            if (supportedImageFileFormats[i] == Vintasoft.Twain.TwainImageFileFormat.Jpeg)
            {
                isJpegFileFormatSupported = true;
                break;
            }
        }
        //
        if (!isJpegFileFormatSupported)
        {
            // close the device
            device.Close();
            // close the device manager
            deviceManager.Close();
            //
            return;
        }

        // specify that File transfer mode must be used
        device.TransferMode = Vintasoft.Twain.TransferMode.File;
        // save images as JPEG files
        device.FileFormat = Vintasoft.Twain.TwainImageFileFormat.Jpeg;
        // set JPEG quality
        device.FileJpegQuality = 50;

        int acquiredImageCount = 0;

        // acquire images from device
        Vintasoft.Twain.AcquireModalState acquireModalState;
        do
        {
            acquireModalState = device.AcquireModal();
            switch (acquireModalState)
            {
                case Vintasoft.Twain.AcquireModalState.ImageAcquiring:
                    // set the filename for image
                    device.FileName = string.Format("test{0}.jpg", acquiredImageCount);
                    break;

                case Vintasoft.Twain.AcquireModalState.ImageAcquired:
                    // image is already saved to disk as JPEG file

                    // specify name for next acquired image
                    acquiredImageCount++;
                    break;
            }
        }
        while (acquireModalState != Vintasoft.Twain.AcquireModalState.None);

        // close the device
        device.Close();

        // close the device manager
        deviceManager.Close();
    }
}

VB.NET

''' <summary>
''' Starts synchronous acquisition of image from TWAIN device and specifies that acquired JPEG compressed images must be saved directly to JPEG files on disk.
''' </summary>
Private Shared Sub StartSynchronousTwainScanningAndSpecifyThatJpegCompressedImagesMustBeSavedDirectlyToJpegFiles()
    ' create the device manager
    Using deviceManager As New Vintasoft.Twain.DeviceManager()
        ' open the device manager
        deviceManager.Open()

        ' get reference to the default device
        Dim device As Vintasoft.Twain.Device = deviceManager.DefaultDevice

        ' specify that device UI must not be used
        device.ShowUI = False

        ' open the device
        device.Open()

        ' check if device driver can save image to disk as JPEG files
        Dim supportedImageFileFormats As Vintasoft.Twain.TwainImageFileFormat() = device.GetSupportedImageFileFormats()
        Dim isJpegFileFormatSupported As Boolean = False
        For i As Integer = 0 To supportedImageFileFormats.Length - 1
            If supportedImageFileFormats(i) = Vintasoft.Twain.TwainImageFileFormat.Jpeg Then
                isJpegFileFormatSupported = True
                Exit For
            End If
        Next
        '
        If Not isJpegFileFormatSupported Then
            ' close the device
            device.Close()
            ' close the device manager
            deviceManager.Close()
            '
            Return
        End If

        ' specify that File transfer mode must be used
        device.TransferMode = Vintasoft.Twain.TransferMode.File
        ' save images as JPEG files
        device.FileFormat = Vintasoft.Twain.TwainImageFileFormat.Jpeg
        ' set JPEG quality
        device.FileJpegQuality = 50

        Dim acquiredImageCount As Integer = 0

        ' acquire images from device
        Dim acquireModalState As Vintasoft.Twain.AcquireModalState
        Do
            acquireModalState = device.AcquireModal()
            Select Case acquireModalState
                Case Vintasoft.Twain.AcquireModalState.ImageAcquiring
                    ' set the filename for image
                    device.FileName = String.Format("test{0}.jpg", acquiredImageCount)
                    Exit Select

                Case Vintasoft.Twain.AcquireModalState.ImageAcquired
                    ' image is already saved to disk as JPEG file

                    ' specify name for next acquired image
                    acquiredImageCount += 1
                    Exit Select
            End Select
        Loop While acquireModalState <> Vintasoft.Twain.AcquireModalState.None

        ' close the device
        device.Close()

        ' close the device manager
        deviceManager.Close()
    End Using
End Sub

3. С помощью JPEG кодека TWAIN драйвера для режима передачи Memory

Драйвер TWAIN должен иметь встроенный кодек JPEG - вы можете проверить это с помощью метода Vintasoft.Twain.Device.GetSupportedImageCompressions.
Драйвер TWAIN возвращает полученное изображение в виде потока JPEG.
Сжатие JPEG можно установить с помощью свойства Vintasoft.Twain.Device.ImageCompression.
Качество файла JPEG можно установить с помощью характеристики Vintasoft.Twain.DeviceCapabilityId.IJpegQuality.

Вот C#/VB.NET код, который демонстрирует, как отсканировать изображение в виде потока JPEG и сохранить его в файл на диске:

/// <summary>
/// Synchronously acquires JPEG compressed images from TWAIN device and saves images to JPEG files.
/// </summary>
static void AcquireJpegCompressedImagesFromTwainDeviceAndSaveImagesToJpegFiles()
{
    // create the device manager
    using (Vintasoft.Twain.DeviceManager deviceManager = new Vintasoft.Twain.DeviceManager())
    {
        // open the device manager
        deviceManager.Open();

        // get reference to the default device
        Vintasoft.Twain.Device device = deviceManager.DefaultDevice;

        // specify that device UI must not be used
        device.ShowUI = false;

        // open the device
        device.Open();

        // check if device driver can return image data as JPEG stream
        Vintasoft.Twain.TwainImageCompression[] supportedImageCompressions = device.GetSupportedImageCompressions();
        bool isJpegCompressionSupported = false;
        for (int i = 0; i < supportedImageCompressions.Length; i++)
        {
            if (supportedImageCompressions[i] == Vintasoft.Twain.TwainImageCompression.Jpeg)
            {
                isJpegCompressionSupported = true;
                break;
            }
        }
        //
        if (!isJpegCompressionSupported)
        {
            // close the device
            device.Close();
            // close the device manager
            deviceManager.Close();
            //
            return;
        }

        // specify that Memory transfer mode must be used
        device.TransferMode = Vintasoft.Twain.TransferMode.Memory;
        // set JPEG compression for image data
        device.ImageCompression = Vintasoft.Twain.TwainImageCompression.Jpeg;
        // set JPEG quality
        Vintasoft.Twain.DeviceCapability jpegQualityCap = device.Capabilities.Find(Vintasoft.Twain.DeviceCapabilityId.IJpegQuality);
        if (jpegQualityCap != null)
            jpegQualityCap.SetValue((int)50);

        // acquire images from device
        Vintasoft.Twain.AcquireModalState acquireModalState;
        do
        {
            acquireModalState = device.AcquireModal();
            switch (acquireModalState)
            {
                case Vintasoft.Twain.AcquireModalState.ImageAcquired:
                    // save acquired image to disk, SDK will save JPEG stream received from device driver
                    device.AcquiredImage.Save("test.jpg");

                    // dispose the acquired image
                    device.AcquiredImage.Dispose();
                    break;
            }
        }
        while (acquireModalState != Vintasoft.Twain.AcquireModalState.None);

        // close the device
        device.Close();

        // close the device manager
        deviceManager.Close();
    }
}

VB.NET

''' <summary>
''' Synchronously acquires JPEG compressed images from TWAIN device and saves images to JPEG files.
''' </summary>
Private Shared Sub AcquireJpegCompressedImagesFromTwainDeviceAndSaveImagesToJpegFiles()
    ' create the device manager
    Using deviceManager As New Vintasoft.Twain.DeviceManager()
        ' open the device manager
        deviceManager.Open()

        ' get reference to the default device
        Dim device As Vintasoft.Twain.Device = deviceManager.DefaultDevice

        ' specify that device UI must not be used
        device.ShowUI = False

        ' open the device
        device.Open()

        ' check if device driver can return image data as JPEG stream
        Dim supportedImageCompressions As Vintasoft.Twain.TwainImageCompression() = device.GetSupportedImageCompressions()
        Dim isJpegCompressionSupported As Boolean = False
        For i As Integer = 0 To supportedImageCompressions.Length - 1
            If supportedImageCompressions(i) = Vintasoft.Twain.TwainImageCompression.Jpeg Then
                isJpegCompressionSupported = True
                Exit For
            End If
        Next
        '
        If Not isJpegCompressionSupported Then
            ' close the device
            device.Close()
            ' close the device manager
            deviceManager.Close()
            '
            Return
        End If

        ' specify that Memory transfer mode must be used
        device.TransferMode = Vintasoft.Twain.TransferMode.Memory
        ' set JPEG compression for image data
        device.ImageCompression = Vintasoft.Twain.TwainImageCompression.Jpeg
        ' set JPEG quality
        Dim jpegQualityCap As Vintasoft.Twain.DeviceCapability = device.Capabilities.Find(Vintasoft.Twain.DeviceCapabilityId.IJpegQuality)
        If jpegQualityCap IsNot Nothing Then
            jpegQualityCap.SetValue(CInt(50))
        End If

        ' acquire images from device
        Dim acquireModalState As Vintasoft.Twain.AcquireModalState
        Do
            acquireModalState = device.AcquireModal()
            Select Case acquireModalState
                Case Vintasoft.Twain.AcquireModalState.ImageAcquired
                    ' save acquired image to disk, SDK will save JPEG stream received from device driver
                    device.AcquiredImage.Save("test.jpg")

                    ' dispose the acquired image
                    device.AcquiredImage.Dispose()
                    Exit Select
            End Select
        Loop While acquireModalState <> Vintasoft.Twain.AcquireModalState.None

        ' close the device
        device.Close()

        ' close the device manager
        deviceManager.Close()
    End Using
End Sub

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