Ruby 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. Ruby

require 'chilkat'

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 = Chilkat::CkPdf.new()
success = pdf.LoadFile("qa_data/pdf/two_column_article.pdf")
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

json = Chilkat::CkJsonObject.new()
jsonOut = Chilkat::CkJsonObject.new()

#  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)
    print pdf.lastErrorText() + "\n";
    exit
end

print "Columns detected: " + jsonOut.IntOf("quality.pages[0].columns").to_s() + "\n";
print "Reading order: " + jsonOut.stringOf("quality.pages[0].readingOrderSource") + "\n";
print jsonOut.stringOf("text") + "\n";

#  "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)
    print pdf.lastErrorText() + "\n";
    exit
end

print "---- columns: none ----" + "\n";
print jsonOut.stringOf("text") + "\n";

#  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
#  ...