Delphi DLL Requires Chilkat v11.7.0+

PDF Placeholders Without a Value: Error, Blank or Keep

See more PDF Text Replacement Examples

Demonstrates the "unusedPlaceholders" option, which decides what happens to a placeholder found on the page that has no value in "placeholders": "error" (the default) makes it a problem with the reason unusedPlaceholder, so nothing is applied; "blank" replaces it with nothing; "keep" leaves it on the page as it is. Delphi DLL

var
success: Boolean;
pdf: HCkPdf;
json: HCkJsonObject;
jsonOut: HCkJsonObject;

begin
success := 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

pdf := CkPdf_Create();
success := CkPdf_LoadFile(pdf,'qa_data/pdf/invoice_template.pdf');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(pdf));
    Exit;
  end;

//  Values for every placeholder except {{po}} (the purchase order number, which this customer has none of).
json := CkJsonObject_Create();
CkJsonObject_UpdateString(json,'placeholders.customer','Acme Corp');
CkJsonObject_UpdateString(json,'placeholders.date','2026-10-18');
CkJsonObject_UpdateString(json,'placeholders.qty1','2');
CkJsonObject_UpdateString(json,'placeholders.desc1','Cordless drill, 18 V');
CkJsonObject_UpdateString(json,'placeholders.price1','$460.00');
CkJsonObject_UpdateString(json,'placeholders.amount1','$920.00');
CkJsonObject_UpdateString(json,'placeholders.qty2','6');
CkJsonObject_UpdateString(json,'placeholders.desc2','Galvanized hinge, 4 inch');
CkJsonObject_UpdateString(json,'placeholders.price2','$12.50');
CkJsonObject_UpdateString(json,'placeholders.amount2','$75.00');
CkJsonObject_UpdateString(json,'placeholders.subtotal','$995.00');
CkJsonObject_UpdateString(json,'placeholders.taxRate','7.35%');
CkJsonObject_UpdateString(json,'placeholders.tax','$73.13');
CkJsonObject_UpdateString(json,'placeholders.total','$1,068.13');

jsonOut := CkJsonObject_Create();

//  The default, "error": the unfilled {{po}} is a problem and nothing would be applied.
success := CkPdf_TextReplace(pdf,'check',json,jsonOut);
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(pdf));
    Exit;
  end;
Memo1.Lines.Add('error (default): ok = ' + IntToStr(Ord(CkJsonObject_BoolOf(jsonOut,'ok'))) + ', problem: ' + CkJsonObject__stringOf(jsonOut,'problems[0].field')
     + ' ' + CkJsonObject__stringOf(jsonOut,'problems[0].reason'));

//  "keep": {{po}} stays on the page, literally.
CkJsonObject_UpdateString(json,'unusedPlaceholders','keep');
success := CkPdf_TextReplace(pdf,'check',json,jsonOut);
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(pdf));
    Exit;
  end;
Memo1.Lines.Add('keep: ok = ' + IntToStr(Ord(CkJsonObject_BoolOf(jsonOut,'ok'))));

//  "blank": {{po}} is replaced by nothing, leaving "PO Number:" with an empty value.
CkJsonObject_UpdateString(json,'unusedPlaceholders','blank');
success := CkPdf_TextReplace(pdf,'apply',json,jsonOut);
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(pdf));
    Exit;
  end;
Memo1.Lines.Add('blank: applied = ' + IntToStr(Ord(CkJsonObject_BoolOf(jsonOut,'applied'))));

success := CkPdf_WriteFile(pdf,'qa_output/invoice_no_po.pdf');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(pdf));
    Exit;
  end;

//  Sample output:

//  error (default): ok = false, problem: po unusedPlaceholder
//  keep: ok = true
//  blank: applied = true

CkPdf_Dispose(pdf);
CkJsonObject_Dispose(json);
CkJsonObject_Dispose(jsonOut);