C Requires Chilkat v11.7.0+

Extract Text from a Two-Column PDF

See more PDF Text Extraction Examples

Demonstrates how multi-column pages are read. By default the columns are detected and each column is read top to bottom before the next ("columns": "auto"); "columns": "none" reads the full page width line by line, which interleaves the columns. The quality report tells how many columns were found. 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 two-column PDF used in this example is available at two_column_article.pdf

    pdf = CkPdf_Create();
    success = CkPdf_LoadFile(pdf,"qa_data/pdf/two_column_article.pdf");
    if (success == FALSE) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        return;
    }

    json = CkJsonObject_Create();
    jsonOut = CkJsonObject_Create();

    //  With the default options the columns are detected, and the text of the left column
    //  comes before the text of the right column.
    success = CkPdf_ExtractText(pdf,"text",json,jsonOut);
    if (success == FALSE) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkJsonObject_Dispose(jsonOut);
        return;
    }

    printf("Columns detected: %d\n",CkJsonObject_IntOf(jsonOut,"quality.pages[0].columns"));
    printf("Reading order: %s\n",CkJsonObject_stringOf(jsonOut,"quality.pages[0].readingOrderSource"));
    printf("%s\n",CkJsonObject_stringOf(jsonOut,"text"));

    //  "none" switches column detection off: the page is read across its full width, line by line,
    //  so each output line holds a line of the left column followed by a line of the right column.
    //  This is rarely wanted, but it shows what the detection does.
    CkJsonObject_UpdateString(json,"columns","none");
    CkJsonObject_UpdateString(json,"layout","lines");
    success = CkPdf_ExtractText(pdf,"text",json,jsonOut);
    if (success == FALSE) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkJsonObject_Dispose(jsonOut);
        return;
    }

    printf("---- columns: none ----\n");
    printf("%s\n",CkJsonObject_stringOf(jsonOut,"text"));

    //  Sample output (abbreviated):

    //  Columns detected: 2
    //  Reading order: visual
    //  The Harbor Lighthouse, Season Two
    //  
    //  The harbor lighthouse was built in 1874 to mark the entrance to the inner channel. It operated continuously until 1968, ...
    //  
    //  The restoration society took ownership in 2021 with three goals: ...
    //  ...
    //  The lantern room frame was stripped, primed and repainted in the original dark green. ...
    //  ...
    //  ---- columns: none ----
    //  The Harbor Lighthouse, Season Two
    //  The harbor lighthouse was built in 1874 to The lantern room frame was stripped, primed
    //  mark the entrance to the inner channel. It and repainted in the original dark green. New
    //  ...


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

    }