B4X Requires Chilkat v11.7.0+

Replace the Value After a Label in a PDF (Re-issue an Invoice)

See more PDF Text Replacement Examples

Demonstrates replacing the values that follow labels such as "Invoice Number:" on a PDF that has no placeholders -- an ordinary invoice. Each entry of the "labels" array names a label as it appears on the page and the new value; the value replaces the rest of the label's line. Label matching ignores case, extra spaces and a trailing colon. The replaced text is read back with ExtractText to confirm it. 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 invoice_labels.pdf

Dim pdf As ChilkatPdf
pdf.Initialize("pdf")
success = pdf.LoadFile("qa_data/pdf/invoice_labels.pdf")
If success = False Then
    Log(pdf.LastErrorText)
    Return
End If


'  The invoice has lines such as "Invoice Number:   INV-2026-0412" and "Total Due:  $1,234.53".
'  Each label's new value replaces whatever follows the label on its line.
Dim json As ChilkatJsonObject
json.Initialize
json.UpdateString("labels[0].label", "Invoice Number:")
json.UpdateString("labels[0].value", "INV-2026-0500")
json.UpdateString("labels[1].label", "Invoice Date:")
json.UpdateString("labels[1].value", "April 2, 2026")
json.UpdateString("labels[2].label", "customer")
json.UpdateString("labels[2].value", "Contoso Ltd")
json.UpdateString("labels[3].label", "Total Due:")
json.UpdateString("labels[3].value", "$1,999.99")

Dim jsonOut As ChilkatJsonObject
jsonOut.Initialize
success = pdf.TextReplace("apply", json, jsonOut)
If success = False Then
    Log("Not applied: " & jsonOut.Emit)
    If success = False Then
        Log(pdf.LastErrorText)
        Return
    End If

End If


Dim i As Int = 0
Dim count_i As Int = jsonOut.SizeOfArray("replacements")
Do While i < count_i
    jsonOut.I = i
    Log("Replaced the value of " & Chr(34) & jsonOut.StringOf("replacements[i].label") & Chr(34) & " on page " & jsonOut.StringOf("replacements[i].pages"))
    i = i + 1
Loop

success = pdf.WriteFile("qa_output/invoice_reissued.pdf")
If success = False Then
    Log(pdf.LastErrorText)
    Return
End If


'  Read the new values back with ExtractText's label option.
Dim jsonRead As ChilkatJsonObject
jsonRead.Initialize
Dim jsonText As ChilkatJsonObject
jsonText.Initialize
jsonRead.UpdateString("label", "Total Due")
jsonRead.UpdateString("labelValue", "right")
success = pdf.ExtractText("text", jsonRead, jsonText)
If success = False Then
    Log(pdf.LastErrorText)
    Return
End If

Log("Total Due is now: " & jsonText.StringOf("text"))

'  Sample output:

'  Replaced the value of "Invoice Number:" on page 1
'  Replaced the value of "Invoice Date:" on page 1
'  Replaced the value of "customer" on page 1
'  Replaced the value of "Total Due:" on page 1
'  Total Due is now: $1,999.99