update: change pdf text parser to pymupdf4llm

[tungsten106]

Using pymupdf4llm instead of pdfminer to parse pdf contents into markdown formats, as suggested by #131.

Pros and Cons:

• pdfminer extract texts only, generated files have no heading, titles, etc. pymupdf4llm, however, could perform a nice markdown featrues including different levels of heading, code blocks and images (could be saved to specific path, but not included in this commit)
• However, pymupdf4llm may easily create lines of digits which belongs to plots, and create non-existing tables. This is a common problem to most PDF parsers, except those using ocr models (such as markers, MinerU).

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[alphaleadership]

maybe this can patch #142

[l-lumin]

I think it's better to let the user choose the engine rather than replacing it

[afourney]

I think it's better to let the user choose the engine rather than replacing it

I agree. There are pros and cons to each. The main thing is to allow a common interface.

Can you propose an interface for this? One option is to just call register_page_converter externally, and the precedence logic would give precedence to whichever converter is registered later. (see here for example: https://github.com/microsoft/markitdown/blob/925c4499f72757abcf6cb521ee10e4844967af3d/src/markitdown/_markitdown.py#L1269C1-L1287C1)

Another option would be to see which dependencies are installed (though this is more opaque)

[tungsten106]

I think it's better to let the user choose the engine rather than replacing it

I agree. There are pros and cons to each. The main thing is to allow a common interface.

Can you propose an interface for this? One option is to just call register_page_converter externally, and the precedence logic would give precedence to whichever converter is registered later. (see here for example: https://github.com/microsoft/markitdown/blob/925c4499f72757abcf6cb521ee10e4844967af3d/src/markitdown/_markitdown.py#L1269C1-L1287C1)

Another option would be to see which dependencies are installed (though this is more opaque)

I have added a parameter pdf_engine to let the user choose engine. For example,

source = "https://arxiv.org/pdf/2308.08155v2.pdf"
markitdown.convert(source, pdf_engine="pymupdf4llm")  # use pymupdf4llm
markitdown.convert(source, pdf_engine="pdfminer")  # use pdfminer

[l-lumin]

could you add test for pymupdf4llm?

[l-lumin]

This part doesn't return anything. Could you update it? Maybe add a warning message?

[l-lumin]

I think pdf_engine should be a named parameter in the function instead of being accessed via kwargs. This provides more clarity and ensures better handling of default values

[tungsten106]

Thanks for you suggestion. I have added it to a named parameters ( I was meant to align with other converters' parameter definition), and added the exception case when pdf_engine is not valid. The new test cases could be seen on my new commit.

[l-lumin]

This is optional, but adding one more named parameter could make this more customizable, like:

def convert(self, local_path, engine: Literal['pdfminer', 'pymupdf4llm']='pdfminer', engine_kwargs=None, **kwargs) -> Union[None, DocumentConverterResult]:

[l-lumin]

I think don't need this. Let me know if you need help setting up the test!

[l-lumin]

remove this

[l-lumin]

This is optional, but adding one more named parameter could make this more customizable, like:

def convert(self, local_path, engine: Literal['pdfminer', 'pymupdf4llm']='pdfminer', engine_kwargs=None, **kwargs) -> Union[None, DocumentConverterResult]:

[l-lumin]

I'd suggest checking the engine first. You could use _engines to define the allowed engines

_engines: Mapping[str, Any] = {
        "pdfminer": pdfminer,
        "pymupdf4llm": pymupdf4llm,
    }
    
###
if engine is not None and engine not in self._engines:
    raise