B4X Requires Chilkat v11.7.0+

How a PDF Watermark Is Stored: artifact, annotation, layer or content

See more PDF Watermark Examples

Demonstrates the approach member, which decides how the watermark is stored and therefore what can be done with it afterwards. artifact (the default) is marked content that viewers draw, text extraction leaves out and Chilkat can remove later. annotation is a Watermark annotation, always on top, and the only approach allowed on a signed PDF while PreserveSignatures is true. layer is an optional-content layer the viewer can hide and that can be made print-only. content draws straight into the page with no marker: visible everywhere and the tamper-resistant choice, but by design it can never be listed or removed again. B4X

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 two_page_memo.pdf

Dim json As ChilkatJsonObject
json.Initialize
Dim jsonOut As ChilkatJsonObject
jsonOut.Initialize
Dim filter As ChilkatJsonObject
filter.Initialize

'  The same watermark stored four different ways, each in its own copy of the document.
Dim pdf As ChilkatPdf
pdf.Initialize("pdf")
success = pdf.LoadFile("qa_data/pdf/two_page_memo.pdf")
If success = False Then
    Log(pdf.LastErrorText)
    Return
End If


json.UpdateString("type", "text")
json.UpdateString("text", "DRAFT")
json.UpdateString("id", "draft")
json.UpdateString("approach", "artifact")
success = pdf.Watermark("add", json, jsonOut)
If success = False Then
    Log(pdf.LastErrorText)
    Return
End If


'  detect answers whether anything matching the filter is in the document.  Finding nothing is
'  still success: "found" is simply false.
filter.UpdateString("id", "draft")
success = pdf.Watermark("detect", filter, jsonOut)
If success = False Then
    Log(pdf.LastErrorText)
    Return
End If

Log("artifact: found = " & jsonOut.BoolOf("found"))

'  An annotation: always drawn on top, and the one approach a signed PDF accepts.
Dim pdf2 As ChilkatPdf
pdf2.Initialize("pdf2")
success = pdf2.LoadFile("qa_data/pdf/two_page_memo.pdf")
If success = False Then
    Log(pdf2.LastErrorText)
    Return
End If

json.UpdateString("approach", "annotation")
success = pdf2.Watermark("add", json, jsonOut)
If success = False Then
    Log(pdf2.LastErrorText)
    Return
End If

success = pdf2.Watermark("detect", filter, jsonOut)
If success = False Then
    Log(pdf2.LastErrorText)
    Return
End If

Log("annotation: found = " & jsonOut.BoolOf("found"))

'  A layer, which the viewer's layers panel can switch off.
Dim pdf3 As ChilkatPdf
pdf3.Initialize("pdf3")
success = pdf3.LoadFile("qa_data/pdf/two_page_memo.pdf")
If success = False Then
    Log(pdf3.LastErrorText)
    Return
End If

json.UpdateString("approach", "layer")
json.UpdateString("layer.name", "Draft marking")
success = pdf3.Watermark("add", json, jsonOut)
If success = False Then
    Log(pdf3.LastErrorText)
    Return
End If

success = pdf3.Watermark("detect", filter, jsonOut)
If success = False Then
    Log(pdf3.LastErrorText)
    Return
End If

Log("layer: found = " & jsonOut.BoolOf("found"))

'  Drawn into the page content with no marker.  There is nothing to find afterwards, which is the
'  point of it: it cannot be stripped out by a tool that removes watermarks.
Dim pdf4 As ChilkatPdf
pdf4.Initialize("pdf4")
success = pdf4.LoadFile("qa_data/pdf/two_page_memo.pdf")
If success = False Then
    Log(pdf4.LastErrorText)
    Return
End If

json.UpdateString("approach", "content")
success = pdf4.Watermark("add", json, jsonOut)
If success = False Then
    Log(pdf4.LastErrorText)
    Return
End If

success = pdf4.Watermark("detect", filter, jsonOut)
If success = False Then
    Log(pdf4.LastErrorText)
    Return
End If

Log("content: found = " & jsonOut.BoolOf("found"))

'  Sample output:

'  artifact: found = True
'  annotation: found = True
'  layer: found = True
'  content: found = False