C++ Requires Chilkat v11.7.0+

Get Every Occurrence of a Label in a PDF

See more PDF Text Extraction Examples

Demonstrates the "labelOccurrence" option. When the same label appears more than once (for example "Total:" on each of several receipts), "first" (the default) uses the first occurrence, "all" returns every occurrence with its page, and a number selects one occurrence. C++

#include <CkPdf.h>
#include <CkJsonObject.h>

void ChilkatSample(void)
    {
    bool 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 (three receipts, one per page) is available at three_receipts.pdf

    CkPdf pdf;
    success = pdf.LoadFile("qa_data/pdf/three_receipts.pdf");
    if (success == false) {
        std::cout << pdf.lastErrorText() << "\r\n";
        return;
    }

    CkJsonObject json;
    CkJsonObject jsonOut;

    //  Each of the three pages is a receipt with a "Total:" line.
    json.UpdateString("label","Total");
    json.UpdateString("labelValue","right");

    //  By default only the first occurrence (in reading order) is used.
    success = pdf.ExtractText("text",json,jsonOut);
    if (success == false) {
        std::cout << pdf.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "First total: " << jsonOut.stringOf("text") << "\r\n";

    //  labelOccurrence "all" returns every occurrence.  The "text" member holds the values joined
    //  by line breaks, and labelMatches has one entry per occurrence with its page.
    json.UpdateString("labelOccurrence","all");
    success = pdf.ExtractText("text",json,jsonOut);
    if (success == false) {
        std::cout << pdf.lastErrorText() << "\r\n";
        return;
    }

    int i = 0;
    int count_i = jsonOut.SizeOfArray("labelMatches");
    while (i < count_i) {
        jsonOut.put_I(i);
        std::cout << "Page " << jsonOut.IntOf("labelMatches[i].page") << " total: " << jsonOut.stringOf("labelMatches[i].text") << "\r\n";
        i = i + 1;
    }

    //  A number selects one occurrence: 2 is the second.
    json.UpdateInt("labelOccurrence",2);
    success = pdf.ExtractText("text",json,jsonOut);
    if (success == false) {
        std::cout << pdf.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Second total: " << jsonOut.stringOf("text") << "\r\n";

    //  The occurrences are counted over the selected pages, so combining "pages" with the label
    //  is another way to pick one receipt:
    json.UpdateString("labelOccurrence","first");
    json.UpdateString("pages","3");
    json.UpdateString("label","Receipt No.");
    success = pdf.ExtractText("text",json,jsonOut);
    if (success == false) {
        std::cout << pdf.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Receipt number on page 3: " << jsonOut.stringOf("text") << "\r\n";

    //  Sample output:

    //  First total: $19.86
    //  Page 1 total: $19.86
    //  Page 2 total: $17.34
    //  Page 3 total: $23.62
    //  Second total: $17.34
    //  Receipt number on page 3: 1003
    }