VB.NET Requires Chilkat v11.7.0+

Tile a Watermark Across a PDF Page

See more PDF Watermark Examples

Demonstrates a tiled watermark, which repeats the stamp over the whole page instead of placing it once. Tiling overrides position.align; tile.spacingX and spacingY set the gaps, and tile.stagger offsets alternate rows by half a tile so the pattern does not line up in columns. A faint tiled stamp carrying the name or address is the usual way to mark a document so that a leaked copy can be traced back, and zOrder back keeps it behind the text where it does not hinder reading. VB.NET

Dim success As Boolean = False

'  This example requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

'  The PDF used in this example is available at long_report.pdf

Dim pdf As New Chilkat.Pdf
success = pdf.LoadFile("qa_data/pdf/long_report.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


Dim json As New Chilkat.JsonObject
json.UpdateString("type","text")

'  {date:FORMAT} is replaced per page when the watermark is added.  The other placeholders are
'  {page}, {pages} and {filename}; {{ gives a literal brace.
json.UpdateString("text","jdoe@example.com  {date:yyyy-MM-dd}")
json.UpdateString("id","trace")
json.UpdateString("zOrder","back")
json.UpdateNumber("font.size","14")
json.UpdateNumber("opacity","0.15")
json.UpdateNumber("rotation","30")

json.UpdateBool("tile.enabled",True)
json.UpdateNumber("tile.spacingX","60")
json.UpdateNumber("tile.spacingY","80")
json.UpdateBool("tile.stagger",True)

Dim jsonOut As New Chilkat.JsonObject
success = pdf.Watermark("add",json,jsonOut)
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("id: " & jsonOut.StringOf("id") & " pages: " & jsonOut.StringOf("pages"))

success = pdf.WriteFile("qa_output/report_traced.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


'  Sample output:

'  id: trace pages: 1-3