' path to an image file
Private _filePath As String = String.Empty

''' <summary>
''' Clears image collection of image viewer and
''' adds image(s) to an image collection of image viewer.
''' </summary>
Private Sub openImageButton_Click(sender As Object, e As System.EventArgs)
    ' select an image file
    If openFileDialog1.ShowDialog() = System.Windows.Forms.DialogResult.OK Then
        ' clear image collection of the image viewer
        annotationViewer1.Images.ClearAndDisposeItems()
        ' save a path to an image file
        _filePath = openFileDialog1.FileName
        ' add image file to an image collection of the image viewer
        annotationViewer1.Images.Add(openFileDialog1.FileName, False)
    End If
End Sub

''' <summary>
''' Saves changes in image collection to the source file.
''' </summary>
Private Sub saveButton_Click(sender As Object, e As System.EventArgs)
    ' create an encoder for image file
    Dim encoder As Vintasoft.Imaging.Codecs.Encoders.EncoderBase = Vintasoft.Imaging.Codecs.Encoders.AvailableEncoders.CreateEncoder(_filePath)
    ' specify that image collection must be switched to the saved image file
    encoder.SaveAndSwitchSource = True
    ' save the image collection to a file
    annotationViewer1.Images.SaveSync(_filePath, encoder)
End Sub

''' <summary>
''' Saves image collection to a new source.
''' </summary>
Private Sub saveAsImageButton_Click(sender As Object, e As System.EventArgs)
    ' select an image file
    If saveFileDialog1.ShowDialog() = System.Windows.Forms.DialogResult.OK Then
        ' save the image collection to a file
        annotationViewer1.Images.SaveSync(saveFileDialog1.FileName)
    End If
End Sub

''' <summary>
''' Burns an annotation collection on image.
''' </summary>
Private Sub burnImageButton_Click(sender As Object, e As System.EventArgs)
    annotationViewer1.AnnotationViewController.BurnAnnotationCollectionOnImage(annotationViewer1.Image)
End Sub

''' <summary>
''' Adds rectangle annotation data to the annotation collection of focused image and
''' starts building of rectangle annotation.
''' </summary>
Private Sub addAndBuildRectangleAnnotationButton_Click(sender As Object, e As System.EventArgs)
    ' change the annotation interaction mode to Author.
    annotationViewer1.AnnotationInteractionMode = Vintasoft.Imaging.Annotation.UI.AnnotationInteractionMode.Author

    ' create the rectangle annotation data
    Dim rectData As New Vintasoft.Imaging.Annotation.RectangleAnnotationData()

    ' add annotation to the annotation collection of focused image and
    ' start building of annotation
    annotationViewer1.AddAndBuildAnnotation(rectData)
End Sub

''' <summary>
''' Adds rectangle annotation data to the annotation collection of focused image.
''' </summary>
Private Sub addAndRectangleAnnotationButton_Click(sender As Object, e As System.EventArgs)
    ' change the annotation interaction mode to Author.
    annotationViewer1.AnnotationInteractionMode = Vintasoft.Imaging.Annotation.UI.AnnotationInteractionMode.Author

    ' create the rectangle annotation data
    Dim rectData As New Vintasoft.Imaging.Annotation.RectangleAnnotationData()

    ' get focused image
    Dim image As Vintasoft.Imaging.VintasoftImage = annotationViewer1.Image
    Dim width As Double = image.Width
    Dim height As Double = image.Height

    ' convert pixels to device independent pixels
    width = Vintasoft.Imaging.Utils.UnitOfMeasureConverter.ConvertToDeviceIndependentPixels(width, Vintasoft.Imaging.UnitOfMeasure.Pixels, image.Resolution.Horizontal)
    height = Vintasoft.Imaging.Utils.UnitOfMeasureConverter.ConvertToDeviceIndependentPixels(height, Vintasoft.Imaging.UnitOfMeasure.Pixels, image.Resolution.Vertical)

    ' set location of rectangle annotation data
    rectData.Location = New System.Drawing.PointF(CSng(width / 2), CSng(height / 2))
    ' set size of rectangle annotation data
    rectData.Size = New System.Drawing.SizeF(CSng(width * 0.3), CSng(height * 0.3))

    ' add annotation to the annotation collection of focused image
    annotationViewer1.AnnotationDataCollection.Add(rectData)
    ' select annotation
    annotationViewer1.FocusedAnnotationData = rectData
End Sub

// path to an image file
private string _filePath = string.Empty;

/// <summary>
/// Clears image collection of image viewer and
/// adds image(s) to an image collection of image viewer.
/// </summary>
private void openImageButton_Click(object sender, System.EventArgs e)
{
    // select an image file
    if (openFileDialog1.ShowDialog() == System.Windows.Forms.DialogResult.OK)
    {
        // clear image collection of the image viewer
        annotationViewer1.Images.ClearAndDisposeItems();
        // save a path to an image file
        _filePath = openFileDialog1.FileName;
        // add image file to an image collection of the image viewer
        annotationViewer1.Images.Add(openFileDialog1.FileName, false);
    }
}

/// <summary>
/// Saves changes in image collection to the source file.
/// </summary>
private void saveButton_Click(object sender, System.EventArgs e)
{
    // create an encoder for image file
    Vintasoft.Imaging.Codecs.Encoders.EncoderBase encoder = 
        Vintasoft.Imaging.Codecs.Encoders.AvailableEncoders.CreateEncoder(_filePath);
    // specify that image collection must be switched to the saved image file
    encoder.SaveAndSwitchSource = true;
    // save the image collection to a file
    annotationViewer1.Images.SaveSync(_filePath, encoder);
}

/// <summary>
/// Saves image collection to a new source.
/// </summary>
private void saveAsImageButton_Click(object sender, System.EventArgs e)
{
    // select an image file
    if (saveFileDialog1.ShowDialog() == System.Windows.Forms.DialogResult.OK)
    {
        // save the image collection to a file
        annotationViewer1.Images.SaveSync(saveFileDialog1.FileName);
    }
}

/// <summary>
/// Burns an annotation collection on image.
/// </summary>
private void burnImageButton_Click(object sender, System.EventArgs e)
{
    annotationViewer1.AnnotationViewController.BurnAnnotationCollectionOnImage(annotationViewer1.Image);
}

/// <summary>
/// Adds rectangle annotation data to the annotation collection of focused image and
/// starts building of rectangle annotation.
/// </summary>
private void addAndBuildRectangleAnnotationButton_Click(object sender, System.EventArgs e)
{
    // change the annotation interaction mode to Author.
    annotationViewer1.AnnotationInteractionMode = Vintasoft.Imaging.Annotation.UI.AnnotationInteractionMode.Author;

    // create the rectangle annotation data
    Vintasoft.Imaging.Annotation.RectangleAnnotationData rectData = 
        new Vintasoft.Imaging.Annotation.RectangleAnnotationData();

    // add annotation to the annotation collection of focused image and
    // start building of annotation
    annotationViewer1.AddAndBuildAnnotation(rectData);
}

/// <summary>
/// Adds rectangle annotation data to the annotation collection of focused image.
/// </summary>
private void addAndRectangleAnnotationButton_Click(object sender, System.EventArgs e)
{
    // change the annotation interaction mode to Author.
    annotationViewer1.AnnotationInteractionMode = Vintasoft.Imaging.Annotation.UI.AnnotationInteractionMode.Author;

    // create the rectangle annotation data
    Vintasoft.Imaging.Annotation.RectangleAnnotationData rectData = 
        new Vintasoft.Imaging.Annotation.RectangleAnnotationData();

    // get focused image
    Vintasoft.Imaging.VintasoftImage image = annotationViewer1.Image;
    double width = image.Width;
    double height = image.Height;

    // convert pixels to device independent pixels
    width = Vintasoft.Imaging.Utils.UnitOfMeasureConverter.ConvertToDeviceIndependentPixels(
        width, Vintasoft.Imaging.UnitOfMeasure.Pixels, image.Resolution.Horizontal);
    height = 
        Vintasoft.Imaging.Utils.UnitOfMeasureConverter.ConvertToDeviceIndependentPixels(
        height, Vintasoft.Imaging.UnitOfMeasure.Pixels, image.Resolution.Vertical);

    // set location of rectangle annotation data
    rectData.Location = new System.Drawing.PointF((float)(width / 2), (float)(height / 2));
    // set size of rectangle annotation data
    rectData.Size = new System.Drawing.SizeF((float)(width * 0.3), (float)(height * 0.3));

    // add annotation to the annotation collection of focused image
    annotationViewer1.AnnotationDataCollection.Add(rectData);
    // select annotation
    annotationViewer1.FocusedAnnotationData = rectData;
}