B4X 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. 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 two-column PDF used in this example is available at two_column_article.pdf

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


Dim json As ChilkatJsonObject
json.Initialize
Dim jsonOut As ChilkatJsonObject
jsonOut.Initialize

'  With the default options the columns are detected, and the text of the left column
'  comes before the text of the right column.
success = pdf.ExtractText("text", json, jsonOut)
If success = False Then
    Log(pdf.LastErrorText)
    Return
End If


Log("Columns detected: " & jsonOut.IntOf("quality.pages[0].columns"))
Log("Reading order: " & jsonOut.StringOf("quality.pages[0].readingOrderSource"))
Log(jsonOut.StringOf("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.
json.UpdateString("columns", "none")
json.UpdateString("layout", "lines")
success = pdf.ExtractText("text", json, jsonOut)
If success = False Then
    Log(pdf.LastErrorText)
    Return
End If


Log("---- columns: none ----")
Log(jsonOut.StringOf("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
'  ...