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Add support for LZWDecode compression #1271

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Lucas-C opened this issue Oct 4, 2024 · 5 comments · May be fixed by #1286
Open

Add support for LZWDecode compression #1271

Lucas-C opened this issue Oct 4, 2024 · 5 comments · May be fixed by #1286

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@Lucas-C
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Lucas-C commented Oct 4, 2024

Please explain your intent
Currently fpdf2 supports 4 compression methods for images:
https://github.com/py-pdf/fpdf2/blob/2.8.0/fpdf/image_parsing.py#L35

The PDF standard specification (cf. PDF32000_2008.pdf section 7.4 Filters) defines several other compression filters, including LZWDecode.

Recently, this filter was implemented by @MartinThoma in our companion library pypdf: py-pdf/pypdf#2883

Describe the solution you'd like
Support LZWDecode for images compression.

@opposss
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opposss commented Oct 7, 2024

Hi!

I'd love to work on this issue can you assign me?

@Lucas-C
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Lucas-C commented Oct 7, 2024

Sure, done!

@Lucas-C
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Lucas-C commented Oct 14, 2024

Hi @opposss

Have you been able to start working on this implementation?
Do you have any questions?

@opposss
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opposss commented Oct 14, 2024

Hi @Lucas-C

Almost done, I will send the PR for review soon.
Before that I would like to ask 2 questions:

  1. Do I understand correctly that I can completely use the code that was written by @MartinThoma ?

  2. Should I add logic to use the LZW filter in case of GIF images or other image formats?

@Lucas-C
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Lucas-C commented Oct 14, 2024

Almost done, I will send the PR for review soon.

Great! 👍

  1. Do I understand correctly that I can completely use the code that was written by @MartinThoma ?

Yes!

  1. Should I add logic to use the LZW filter in case of GIF images or other image formats?

If you can find a mention that this is supported, in the PDF spec (PDF32000_2008.pdf), or that main PDF readers support it (Adobe Acrobat, Sumatra PDF, MuPDF, web browsers...), then yes!

opposss added a commit to opposss/fpdf2 that referenced this issue Oct 15, 2024
@opposss opposss linked a pull request Oct 16, 2024 that will close this issue
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