B4X Requires Chilkat v11.7.0+

Fill a PDF Template: Replace {{placeholders}} with Values

See more PDF Text Replacement Examples

Demonstrates the TextReplace method on an invoice template whose values are written as placeholders such as {{customer}} and {{total}}. The "placeholders" object names each placeholder and the text to put in; every occurrence on the page is replaced, including a placeholder inside a sentence or inside a label such as "Tax ({{taxRate}}):". The text is redrawn with the font the template used, so the result looks like the template, and a value that is right-aligned in the template stays right-aligned. The changes are written by WriteFile. 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_template.pdf

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


'  The template has these placeholders in its page text:
'    {{customer}} (twice: "Bill To:" and the closing sentence), {{date}}, {{po}},
'    two item rows: {{qty1}} {{desc1}} {{price1}} {{amount1}} and {{qty2}} {{desc2}} {{price2}} {{amount2}},
'    {{subtotal}}, "Tax ({{taxRate}}):" with {{tax}}, and {{total}}.
Dim json As ChilkatJsonObject
json.Initialize
json.UpdateString("placeholders.customer", "Acme Corp")
json.UpdateString("placeholders.date", "2026-10-18")
json.UpdateString("placeholders.po", "PO-88213")
json.UpdateString("placeholders.qty1", "2")
json.UpdateString("placeholders.desc1", "Cordless drill, 18 V")
json.UpdateString("placeholders.price1", "$460.00")
json.UpdateString("placeholders.amount1", "$920.00")
json.UpdateString("placeholders.qty2", "6")
json.UpdateString("placeholders.desc2", "Galvanized hinge, 4 inch")
json.UpdateString("placeholders.price2", "$12.50")
json.UpdateString("placeholders.amount2", "$75.00")
json.UpdateString("placeholders.subtotal", "$995.00")
json.UpdateString("placeholders.taxRate", "7.35%")
json.UpdateString("placeholders.tax", "$73.13")
json.UpdateString("placeholders.total", "$1,068.13")

'  "apply" makes every replacement, or none: if any value cannot be drawn with the
'  template's font, the method returns false, the PDF is unchanged, and jsonOut says why.
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


'  One entry per placeholder: the pages it was found on and how many times it was replaced.
Dim i As Int = 0
Dim count_i As Int = jsonOut.SizeOfArray("replacements")
Do While i < count_i
    jsonOut.I = i
    Log(jsonOut.StringOf("replacements[i].field") & ": " & jsonOut.IntOf("replacements[i].count") & " on page(s) " & jsonOut.StringOf("replacements[i].pages"))
    i = i + 1
Loop

'  The replacements stay in memory until the PDF is written.
success = pdf.WriteFile("qa_output/invoice_filled.pdf")
If success = False Then
    Log(pdf.LastErrorText)
    Return
End If

Log("Wrote qa_output/invoice_filled.pdf")

'  Sample output:

'  customer: 2 on page(s) 1
'  date: 1 on page(s) 1
'  po: 1 on page(s) 1
'  qty1: 1 on page(s) 1
'  desc1: 1 on page(s) 1
'  price1: 1 on page(s) 1
'  amount1: 1 on page(s) 1
'  qty2: 1 on page(s) 1
'  desc2: 1 on page(s) 1
'  price2: 1 on page(s) 1
'  amount2: 1 on page(s) 1
'  subtotal: 1 on page(s) 1
'  taxRate: 1 on page(s) 1
'  tax: 1 on page(s) 1
'  total: 1 on page(s) 1
'  Wrote qa_output/invoice_filled.pdf