5 ms·

Doesn't rendering to an image require proper parsing of the PDF?

cylemons 1y ago
PDF is more like a glorified svg format than a word format. It only contains info on how the document should look but so semantic information like sentences, paragraphs, etc. Just a bag of characters positioned in certain places.
- Macha 1y ago
  Sometimes the characters aren’t even characters, just paths
  - cylemons 1y ago
    Wouldn't that be very space inefficient to repeat the paths every time a letter appears in the file? Or you mean that glyph Ids don't necessarily map to Unicode?
    - manishsn 1y ago
      sometimes in fancy articles you might see the first letter is large and ornate which is most likely a path also like you said glyph IDs always don't necessarily map to unicode or the creator can intentionally mangle the 'to unicode' map of Identity-H embedded font in the pdf if he is nasty
    - user____name 1y ago
      Outlines are just a practical way of handling less common display cases. Just to give a practical example. Imagine a Star Wars advert that has the Star Wars logo at the top, specified in outlines because that's what every vector logo uses. Below it the typical Star Wars intro text stretched into perspective, also using outlines, because that's the easiest (display engine doesn't need complicated transformation stack), efficient to render (you have to render the outlines anyway), and most robust way (looks the same everywhere), way of implementing transformations in text. You also don't have to supply the font file, which comes with licensing issues, etc. Also whenever compositing and transparency are involved, with color space conversion nonsense, it's more robust to "bake" the effect via constructive geometry operations, etc, to prevent display issues on other devices, which are surprisingly common.
throwaway4496 1y ago
Yes, and don't for a second think this approach of rastering and OCR'ing is sane, let alone a reasonable choice. It is outright absurd.
- yxhuvud 1y ago
  Noone has claimed getting structured data out of pdfs are sane. What you seem to be missing is that there are no sane ways to get a decent output. The reasonable choice would be to not even try, but business needs invalidate that choice. So what remain is the absurd ways to solve the problem.
  - throwaway4496 1y ago
    [flagged]
    - yxhuvud 1y ago
      Well, perhaps you are exposed only to special snowflakes of pdfs that are from a single source and somewhat well formed and easy to extract from. Other, like me, are working at companies that also have lots of PDFs, from many, many different sources, and there are no easy ways to extract structured data or even text in a way that always work.
      - throwaway4496 1y ago
        If you actually read what I have been saying and commenting, you would realise how silly your comment is.

PDF is more like a glorified svg format than a word format. It only contains info on how the document should look but so semantic information like sentences, paragraphs, etc. Just a bag of characters positioned in certain places.

Macha 1y ago
Sometimes the characters aren’t even characters, just paths
- cylemons 1y ago
  Wouldn't that be very space inefficient to repeat the paths every time a letter appears in the file? Or you mean that glyph Ids don't necessarily map to Unicode?
  - manishsn 1y ago
    sometimes in fancy articles you might see the first letter is large and ornate which is most likely a path also like you said glyph IDs always don't necessarily map to unicode or the creator can intentionally mangle the 'to unicode' map of Identity-H embedded font in the pdf if he is nasty
  - user____name 1y ago
    Outlines are just a practical way of handling less common display cases. Just to give a practical example. Imagine a Star Wars advert that has the Star Wars logo at the top, specified in outlines because that's what every vector logo uses. Below it the typical Star Wars intro text stretched into perspective, also using outlines, because that's the easiest (display engine doesn't need complicated transformation stack), efficient to render (you have to render the outlines anyway), and most robust way (looks the same everywhere), way of implementing transformations in text. You also don't have to supply the font file, which comes with licensing issues, etc. Also whenever compositing and transparency are involved, with color space conversion nonsense, it's more robust to "bake" the effect via constructive geometry operations, etc, to prevent display issues on other devices, which are surprisingly common.

throwaway4496 1y ago

Yes, and don't for a second think this approach of rastering and OCR'ing is sane, let alone a reasonable choice. It is outright absurd.

yxhuvud 1y ago
Noone has claimed getting structured data out of pdfs are sane. What you seem to be missing is that there are no sane ways to get a decent output. The reasonable choice would be to not even try, but business needs invalidate that choice. So what remain is the absurd ways to solve the problem.
- throwaway4496 1y ago
  [flagged]
  - yxhuvud 1y ago
    Well, perhaps you are exposed only to special snowflakes of pdfs that are from a single source and somewhat well formed and easy to extract from. Other, like me, are working at companies that also have lots of PDFs, from many, many different sources, and there are no easy ways to extract structured data or even text in a way that always work.
    - throwaway4496 1y ago
      If you actually read what I have been saying and commenting, you would realise how silly your comment is.