Especially important for letters that need to fit into standard envelopes, fold marks are guidelines that help you fold documents accurately. DIN 5008:2011 is a German standard ("Falzmarken") that provides guidelines for document layout and formatting. These marks are used to ensure that when a document is folded, the text will remain in alignment and will fit properly in a standard DL envelope (220 x 110 mm).

Inserting Drawings

To create these marks, you can use the drawing feature of TX Text Control and insert these marks in the header to position them behind the text, overlapping the left margin. The following code shows how to create these fold marks using TX Text Control:

private void InsertFoldingMark(double top, int width, Color color, HeaderFooter headerFooter, TextControl textControl)
{
        textControl.PageUnit = MeasuringUnit.Twips;

        // create a new drawing control
        TXTextControl.Drawing.TXDrawingControl drawing =
                new TXTextControl.Drawing.TXDrawingControl(3000, 1000);

        // create a new line shape object
        TXTextControl.Drawing.Shape shape =
                new TXTextControl.Drawing.Shape(TXTextControl.Drawing.ShapeType.Line);

        // set the color and border width
        shape.ShapeOutline.Color = color;
        shape.ShapeOutline.Width = 20;
        shape.Angle = -45;
        shape.Movable = false;
        shape.Sizable = false;

        // add the shape to the drawing control
        drawing.Shapes.Add(
                shape,
                TXTextControl.Drawing.ShapeCollection.AddStyle.Fill);
        shape.Size = new Size(width, width);

        // create a new drawing frame object from the created drawing control
        TXTextControl.DataVisualization.DrawingFrame frame =
                new TXTextControl.DataVisualization.DrawingFrame(drawing);

        frame.Sizeable = false;
        frame.Moveable = false;

        var leftOffset = textControl.Sections[headerFooter.Section].Format.PageMargins.Left - MmToTwips(12);
        var topOffset = textControl.Sections[headerFooter.Section].Format.PageMargins.Top;

        // add the frame to the document
        headerFooter.Drawings.Add(
                frame, 
                new Point(-(int)leftOffset, 
                (int)(MmToTwips(top) - topOffset)), 
                FrameInsertionMode.BelowTheText | FrameInsertionMode.FixedOnPage);
}

public static double MmToTwips(double mm)
{
        const double mmPerInch = 25.4;
        const double twipsPerInch = 1440;

        double inches = mm / mmPerInch;
        double twips = inches * twipsPerInch;
        return twips;
}

The above function can be called to insert the two typical fold marks and a punch mark:

textControl1.Sections.GetItem().HeadersAndFooters.Add(HeaderFooterType.Header);

HeaderFooter header = textControl1.Sections.GetItem().HeadersAndFooters.GetItem(HeaderFooterType.Header);

// folding mark 1
InsertFoldingMark(87, 500, Color.Black, header, textControl1);

// folding mark 2
InsertFoldingMark(192, 500, Color.Black, header, textControl1);

// punch hole center mark
InsertFoldingMark(148.5, 800, Color.Red, header, textControl1);

These fold marks are inserted into the header of the document. The resulting document looks like this:

Conclusion

Using TX Text Control, you can easily create fold marks for your documents. These marks are especially useful for letters that need to be folded and inserted into standard envelopes. The fold marks are inserted into the header of the document and are positioned behind the text, overlapping the left margin.