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Topic: Re: Image Extraction and Replacement in PDF File
Conf: (P-PDF) Developers, Msg: 57472
Date: 5/29/2002 05:26 PM
At 04:15 AM 11/21/2001 +1100, p-pdf-developer Listmanager wrote:
>Ok, now i like to make sure something before i start to do (am i too rude ?
>sorry for this, I am good in programming language not English !!) .
And he continues to make progress...
>Extract Image from a PDF which is using FLATE Filter ( what i plan to do is
>a) Extract Image data between stream and endstream.
>b) Decompress the data using zlib (we are getting binary data)
>c) compress the data using libjpeg and save it as .jpg. (what function i
>have to call)
That will certainly work.
HOWEVER, consider that by using JPEG (which is a LOSSY
algorithm/format) you may/will end up damaging your data. I would
recommend saving the images as PNG, since it's lossless.
>Insert Image into PDF
>a) uncompress the original image data using libjpeg. (what function i have
If the original image is already JPEG, then you don't have to
decompress at all! Just copy the image data from the file between
stream/endstream and mark the image as using DCTFilter.