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CCITTFaxDecode filter for Acrobat

I writing a app to extract text from a PDF file - I'm able to extract the text if the PDF file is compressed with Flatedecode - But it fails if the compression is CCITTFaxDecode. Can anyone help me to get the filter for CCITTFaxDecode compression. Thanks in advance

Karl Heinz Kremer

Text should never be encoded with CCITTFaxDecode - that is a filter that is only useful for monochrome images (black dots on white paper or vice versa). Are you sure that you need that filter for text extraction?

What environment are you using? Are you using any PDF library (that would be the ideal situation, because you really do not want to write the complete PDF handling from scratch)?

fritzdsa

ASKER

I'm using the code found at http://www.codeproject.com/KB/cpp/ExtractPDFText.aspx
This code assumes that the PDF file has text objects compressed using FlateDecode filter and it uses zlib for uncompressing the streams.
But my PDF files have text behind image and the filter used is CCITTFaxDecode - Now I want to know how do I uncompress this filter. Thanks in advance

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Karl Heinz Kremer

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fritzdsa

ASKER

yes your clue to ignore the image helped as the pdf we were working stored text data a little differently and at the end of the file.

Karl Heinz Kremer

The order of information in a PDF file has no meaning. You need to read up on how the XRef table is used in PDF.