''' <summary>
''' Renders PDF page with the optional content group.
''' </summary>
''' <param name="page">The page of PDF document.</param>
Public Shared Function RenderPdfPageWithOptionalContentGroup(page As Vintasoft.Imaging.Pdf.Tree.PdfPage) As Vintasoft.Imaging.VintasoftImage
    ' get PDF document of page
    Dim document As Vintasoft.Imaging.Pdf.PdfDocument = page.Document

    ' if document has optional content groups then
    If document.OptionalContentProperties IsNot Nothing AndAlso document.OptionalContentProperties.OptionalContentGroups IsNot Nothing Then
        ' get a list of optional content groups of PDF document
        Dim allGroups As System.Collections.Generic.IList(Of Vintasoft.Imaging.Pdf.Tree.OptionalContent.PdfOptionalContentGroup) = document.OptionalContentProperties.OptionalContentGroups

        ' for each optional content group
        For Each group As Vintasoft.Imaging.Pdf.Tree.OptionalContent.PdfOptionalContentGroup In allGroups
            ' set the optional content group as invisible
            document.OptionalContentConfiguration.SetGroupVisibility(group, False)
        Next
    End If

    ' render PDF page
    Dim image As Vintasoft.Imaging.VintasoftImage = page.Render()

    ' return the image of PDF page
    Return image
End Function

/// <summary>
/// Renders PDF page with the optional content group.
/// </summary>
/// <param name="page">The page of PDF document.</param>
public static Vintasoft.Imaging.VintasoftImage RenderPdfPageWithOptionalContentGroup(
    Vintasoft.Imaging.Pdf.Tree.PdfPage page)
{
    // get PDF document of page
    Vintasoft.Imaging.Pdf.PdfDocument document = page.Document;

    // if document has optional content groups then
    if (document.OptionalContentProperties != null &&
        document.OptionalContentProperties.OptionalContentGroups != null)
    {
        // get a list of optional content groups of PDF document
        System.Collections.Generic.IList<Vintasoft.Imaging.Pdf.Tree.OptionalContent.PdfOptionalContentGroup> allGroups =
            document.OptionalContentProperties.OptionalContentGroups;

        // for each optional content group
        foreach (Vintasoft.Imaging.Pdf.Tree.OptionalContent.PdfOptionalContentGroup group in allGroups)
            // set the optional content group as invisible
            document.OptionalContentConfiguration.SetGroupVisibility(group, false);
    }

    // render PDF page
    Vintasoft.Imaging.VintasoftImage image = page.Render();

    // return the image of PDF page
    return image;
}