C 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. C

#include <C_CkPdf.h>
#include <C_CkJsonObject.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkPdf pdf;
    HCkJsonObject json;
    HCkJsonObject jsonOut;

    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) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        return;
    }

    //  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) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkJsonObject_Dispose(jsonOut);
        return;
    }

    printf("error (default): ok = %d, problem: %s %s\n",CkJsonObject_BoolOf(jsonOut,"ok"),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) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkJsonObject_Dispose(jsonOut);
        return;
    }

    printf("keep: ok = %d\n",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) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkJsonObject_Dispose(jsonOut);
        return;
    }

    printf("blank: applied = %d\n",CkJsonObject_BoolOf(jsonOut,"applied"));

    success = CkPdf_WriteFile(pdf,"qa_output/invoice_no_po.pdf");
    if (success == FALSE) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkJsonObject_Dispose(jsonOut);
        return;
    }

    //  Sample output:

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


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

    }