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Show HN: HTML visualization of a PDF file's internal structure

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Re: Show HN: HTML visualization of a PDF file's internal structure

#31

Post by GaggiX »

codetrotter wrote: post #26

Many moons ago I was tasked with extracting data from a bunch of PDFs. I made a tool to visualise how characters were laid out on the page and bounding boxes of all the elements. The project was in the end a complete failure and several people were upset at me for not delivering what I was supposed to. In present day, with the capabilities that are now available with LLMs to extract data from PDFs I 100% would go the…

It reminds me of: https://xkcd.com/1425/

In the same way now with today's AI models the task is easily achievable.

Re: Show HN: HTML visualization of a PDF file's internal structure

#33

Post by jimjimjim »

codetrotter wrote: post #26

Many moons ago I was tasked with extracting data from a bunch of PDFs. I made a tool to visualise how characters were laid out on the page and bounding boxes of all the elements. The project was in the end a complete failure and several people were upset at me for not delivering what I was supposed to. In present day, with the capabilities that are now available with LLMs to extract data from PDFs I 100% would go the…

The LLMs might help with sequencing the characters you extract from the page but actually getting the contents is still difficult. A number of times I've come across a page where the letters of the text are glyphs in a custom font with no mapping to ascii or anything similar or even more common, especially with output from CAD, are letters that are made by drawing lines in the shape of letters so there is nothing identifiable to extract and you are left with OCRing the page to double check the results

Re: Show HN: HTML visualization of a PDF file's internal structure

#35

Post by adelpozo »

it does not have any dependency to a pdf parsing library, correct? That's a cool way to learn to file format and be able to work around weird pdf file. But what was the motivation to not use a library to do the pdf parsing work? is it the case that there is none available? Nice work!

Re: Show HN: HTML visualization of a PDF file's internal structure

#36

Post by macklinkachorn »

codetrotter wrote: post #26

Many moons ago I was tasked with extracting data from a bunch of PDFs. I made a tool to visualise how characters were laid out on the page and bounding boxes of all the elements. The project was in the end a complete failure and several people were upset at me for not delivering what I was supposed to. In present day, with the capabilities that are now available with LLMs to extract data from PDFs I 100% would go the…

In my previous role, I have experienced similar things where the rule-based parsing approach is really tricky to get right and often failed via from edge cases.

We (at https://runtrellis.com/) have been building PDF processing pipeline from the ground up with LLMs and VLMs and have seen close to 100% accuracy even for tricky PDFs. The key is to use rule based engine and references to cross check the data.

Re: Show HN: HTML visualization of a PDF file's internal structure

#37

Post by bob1029 »

codetrotter wrote: post #26

Many moons ago I was tasked with extracting data from a bunch of PDFs. I made a tool to visualise how characters were laid out on the page and bounding boxes of all the elements. The project was in the end a complete failure and several people were upset at me for not delivering what I was supposed to. In present day, with the capabilities that are now available with LLMs to extract data from PDFs I 100% would go the…

Parsing data out of arbitrary PDFs is a cursed mission. PDF can contain images, so you might as well target JPEG directly.

OCR can take you pretty far depending on expectations, but it's never quite far enough in my experience.

Re: Show HN: HTML visualization of a PDF file's internal structure

#38

Post by desgeeko »

adelpozo wrote: post #35

it does not have any dependency to a pdf parsing library, correct? That's a cool way to learn to file format and be able to work around weird pdf file. But what was the motivation to not use a library to do the pdf parsing work? is it the case that there is none available? Nice work!

Correct, PDFSyntax implements everything at the lowest level. You can ignore the HTML visualization and use it as an API to access PDF objects. Why? Because I started a very small tool as a week-end project and I got hooked reading the PDF Specification so it is becoming a general purpose PDF library for Python. I am not familiar with other libraries but I have the impression that mine implements things that are often overlooked in others, like incremental updates.

Re: Show HN: HTML visualization of a PDF file's internal structure

#39

Post by nabaraz »

On a similar note, why haven't PDF been replaced? There are XPS, DjVu and XHTML (EPUB) but they all seem to be targeting different usecase (a packaged HTML file).

What I want is a simple document format that allows embedding other files and metadata without the Adobe's bloat. I should be able to hyperlink within pages, change font-size etc without text overflowing and being able to print in a consistent manner.

Re: Show HN: HTML visualization of a PDF file's internal structure

#40

Post by wetpaws »

nabaraz wrote: post #39

On a similar note, why haven't PDF been replaced? There are XPS, DjVu and XHTML (EPUB) but they all seem to be targeting different usecase (a packaged HTML file). What I want is a simple document format that allows embedding other files and metadata without the Adobe's bloat. I should be able to hyperlink within pages, change font-size etc without text overflowing and being able to print in a consistent manner.

Cause it works and works good enough. Also, immutability is a feature, not a bug
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