Attach a file to a PDF in C#

Nutrient .NET SDK (formerly GdPicture.NET) enables you to attach a file to a PDF in the form of an annotation.

To attach a file to a PDF, follow the steps below.

1. Create a GdPicturePDF object.
2. Specify the origin of the coordinate system with the SetOrigin method. It requires the PdfOrigin enumeration, which accepts the following values:
   • PdfOriginTopLeft
   • PdfOriginTopRight
   • PdfOriginBottomRight
   • PdfOriginBottomLeft
3. Set the measurement unit used to specify the dimensions of the annotation. The SetMeasurementUnit method takes a member of the PdfMeasurementUnit enumeration as an argument. It accepts the following values:
   • PdfMeasurementUnitCentimeter
   • PdfMeasurementUnitMillimeter
   • PdfMeasurementUnitInch
   • PdfMeasurementUnitPoint
   • PdfMeasurementUnitUndefined
4. Open the file you want to attach in the form of a byte array.

5. Select the PDF page where you want to add the annotation using the SelectPage method.
6. Use the AddFileAttachmentAnnot method. It accepts the following parameters:
   • Left — X coordinate of the top-left corner.
   • Top — Y coordinate of the top-left corner.
   • Width — Width of the annotation icon.
   • Height — Height of the annotation icon.
   • Data — The content of the file associated with the annotation object, which is expressed as a binary value.
   • FileName — Name of the attached file.
   • Title — Title of the annotation.
   • Description — Annotation description.
   • color:
     • Red, Green, Blue — RGB values (from 0 to 255).
     • Cyan, Magenta, Yellow, Black — CMYK values (from 0 to 255).
     • Color object — For more information, refer to the color object guide.
   • Opacity — Opacity value of the annotation, where 0 means full transparency and 1 means fully visible. Use the f suffix to convert the double value to float (0.75f).
   • AnnotIcon — Icon type displayed. This uses the PdfFileAttachmentAnnotIcon enumeration. The possible values are the following:
     • None
     • Graph
     • Tag
     • Paperclip
     • PushPin

To add an image file as an annotation to the last page of a PDF, use the following code:

using GdPicturePDF gdpicturePDF = new GdPicturePDF();
string filename = @"C:\temp\source.jpg";
gdpicturePDF.LoadFromFile(@"C:\temp\source.pdf");
// Set the origin of the coordinate system to the bottom-left corner.
gdpicturePDF.SetOrigin(PdfOrigin.PdfOriginBottomLeft);
// Set the measurement unit to centimeters.
gdpicturePDF.SetMeasurementUnit(PdfMeasurementUnit.PdfMeasurementUnitCentimeter);
// Load the image file as a binary array.
byte[] data = File.ReadAllBytes(filename);
// Select the page to attach the file to.
gdpicturePDF.SelectPage(gdpicturePDF.GetPageCount());
// Add an annotation with the image file.
int annotID = gdpicturePDF.AddFileAttachmentAnnot(Left: 5, Top: 5,
    Width: 2, Height: 4, data, filename, "Attachment", "Attachment for review",
    Color.DarkBlue, 0.75f, PdfFileAttachmentAnnotIcon.Paperclip);
gdpicturePDF.SaveToFile(@"C:\temp\output.pdf");

Using gdpicturePDF As GdPicturePDF = New GdPicturePDF()
    Dim filename = "C:\temp\source.jpg"
    gdpicturePDF.LoadFromFile("C:\temp\source.pdf")
    ' Set the origin of the coordinate system to the bottom-left corner.
    gdpicturePDF.SetOrigin(PdfOrigin.PdfOriginBottomLeft)
    ' Set the measurement unit to centimeters.
    gdpicturePDF.SetMeasurementUnit(PdfMeasurementUnit.PdfMeasurementUnitCentimeter)
    ' Load the image file as a binary array.
    Dim data = File.ReadAllBytes(filename)
    ' Select the page to attach the file to.
    gdpicturePDF.SelectPage(gdpicturePDF.GetPageCount())
    ' Add an annotation with the image file.
    Dim annotID As Integer = gdpicturePDF.AddFileAttachmentAnnot(Left:=5, Top:=5,
        Width:=2, Height:=4, data, filename, "Attachment", "Attachment for review",
        Color.DarkBlue, 0.75F, PdfFileAttachmentAnnotIcon.Paperclip)
    gdpicturePDF.SaveToFile("C:\temp\output.pdf")
End Using