ICEpdf
  1. ICEpdf
  2. PDF-438

Extracting text from document doesn't work properly.

          Details

          • Type: Bug Bug
          • Status: Closed
          • Priority: Major Major
          • Resolution: Fixed
          • Affects Version/s: 4.3.2
          • Fix Version/s: 4.3.4
          • Component/s: Core/Parsing
          • Labels:
            None
          • Environment:
            ICEpdf PRO 4.3.2, ICEpdf Viewer

            Description

            While extracting text from attached document I have found that line:

            "last flight (if one was defined for that flight). Regardless of the data,"

            consists of 2 LineText objects:
            1. "last flight (if one was" and
            2. "defined for that flight). Regardless of the data,".

            It looks like space between words "was" and "defined" is missing so if I would search for the word "defined" you will not find it.

            Adding space manualy between LineText objects causes problem in different line:

            "airport reference point latitude/longitude position shows adjacent to the".

            It consists of:
            1. "airport reference p" and
            2. "oint latitude/longitude position shows adjacent to the".

            If I put space between them I will get "airport reference p oint latitude/longitude position shows adjacent to the" and searching for a word "point" fails.
            1. PDF File
              example.pdf
              47 kB
              Evgheni Sadovoi

              Activity

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              Patrick Corless added a comment -

              Targeting 4.3.3

              Show
              Patrick Corless added a comment - Targeting 4.3.3
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              Patrick Corless added a comment -

              I've taken some time to look closer into specifically what is going on with the PDF question. The PDF's text content stream is encoded a bit differently using the "td" token mid line. Normally the "td" are used to sepcify a jump to the next line using the same offset as the previous line.

              That all said we have some code that will try and detect if the y offset is larger enough to justify inserting a new line character. In this case the old y value would be something like 542.1345 and 541.98, visually font look like its drawn at virtually at the same spot but the line feed check passes and a new line inserted because the new value isn't the same as the last.

              The problem is really that of float precision. As a work around I added Math.round on the y offset values to try and do "softer" comparison and avoid the extra line feed being inserted. Overall the fix seems to work quite will on a various documents. I still need to create a new test suite for text extraction to get better measure on any possible regression.

              Show
              Patrick Corless added a comment - I've taken some time to look closer into specifically what is going on with the PDF question. The PDF's text content stream is encoded a bit differently using the "td" token mid line. Normally the "td" are used to sepcify a jump to the next line using the same offset as the previous line. That all said we have some code that will try and detect if the y offset is larger enough to justify inserting a new line character. In this case the old y value would be something like 542.1345 and 541.98, visually font look like its drawn at virtually at the same spot but the line feed check passes and a new line inserted because the new value isn't the same as the last. The problem is really that of float precision. As a work around I added Math.round on the y offset values to try and do "softer" comparison and avoid the extra line feed being inserted. Overall the fix seems to work quite will on a various documents. I still need to create a new test suite for text extraction to get better measure on any possible regression.
              Hide
              Permalink
              Patrick Corless added a comment -

              Closing issue.

              Show
              Patrick Corless added a comment - Closing issue.

                People

                • Assignee:
                  Patrick Corless
                  Reporter:
                  Evgheni Sadovoi
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                  Dates

                  • Created:
                    Updated:
                    Resolved: