Flatten PDF interactive form fields

The following example shows how to flatten the PDF interactive form with GemBox.Pdf.

C#
VB.NET

using GemBox.Pdf;
using GemBox.Pdf.Content;
using GemBox.Pdf.Forms;

class Program
{
    static void Main()
    {
        // If using the Professional version, put your serial key below.
        ComponentInfo.SetLicense("FREE-LIMITED-KEY");

        using (var document = PdfDocument.Load("%InputFileName%"))
        {
            // A flag specifying whether to construct appearance for all form fields in the document.
            bool needAppearances = document.Form.NeedAppearances;

            foreach (var field in document.Form.Fields)
            {
                // Do not flatten button fields.
                if (field.FieldType == PdfFieldType.Button)
                    continue;

                // Construct appearance, if needed.
                if (needAppearances)
                    field.Appearance.Refresh();

                // Get the field's appearance form.
                var fieldAppearance = field.Appearance.Get();

                // If the field doesn't have an appearance, skip it.
                if (fieldAppearance == null)
                    continue;

                // Draw field's appearance on the page.
                field.Page.Content.DrawAnnotation(field);
            }

            // Remove all fields, thus making the document non-interactive,
            // since their appearance is now contained directly in the content of their pages.
            document.Form.Fields.Clear();

            document.Save("FormFlattened.%OutputFileType%");
        }
    }
}

Imports GemBox.Pdf
Imports GemBox.Pdf.Content
Imports GemBox.Pdf.Forms

Module Program

    Sub Main()

        ' If using the Professional version, put your serial key below.
        ComponentInfo.SetLicense("FREE-LIMITED-KEY")

        Using document = PdfDocument.Load("%InputFileName%")

            ' A flag specifying whether to construct appearance for all form fields in the document.
            Dim needAppearances = document.Form.NeedAppearances

            For Each field In document.Form.Fields

                ' Do not flatten button fields.
                If field.FieldType = PdfFieldType.Button Then Continue For

                ' Construct appearance, if needed.
                if needAppearances Then field.Appearance.Refresh()

                ' Get the field's appearance form.
                Dim fieldAppearance = field.Appearance.Get()

                ' If the field doesn't have an appearance, skip it.
                If fieldAppearance Is Nothing Then Continue For

                ' Draw field's appearance on the page.
                field.Page.Content.DrawAnnotation(field)
            Next

            ' Remove all fields, thus making the document non-interactive,
            ' since their appearance is now contained directly in the content of their pages.
            document.Form.Fields.Clear()

            document.Save("FormFlattened.%OutputFileType%")
        End Using
    End Sub
End Module

Screenshot of PDF interactive form fields flattened with GemBox.Pdf

Using the same approach, you can also flatten PdfAnnotations contained in the Annotations property of the PdfPage class.

Another approach of making the PDF form non-interactive is to make all form fields read-only using the ReadOnly property of the PdfField class.

Next steps

GemBox.Pdf is a .NET component that enables developers to read, merge and split PDF files or execute low-level object manipulations from .NET applications in a simple and efficient way.

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Flatten PDF interactive form fields

See also

Next steps