4 ms·

Show HN: PDF Differ

62 points by m4rc1e 3y ago

crtasm 3y ago
Mac app. They're looking for more beta testers.
tomgp 3y ago
Looks interesting! Just a heads up as you seem to be a UK registered limited company : >On business letters, order forms and websites, you must show: >the company’s registered number >its registered office address >where the company is registered (England and Wales, Scotland or Northern Ireland) >the fact that it’s a limited company (usually by spelling out the company’s full name including ‘Limited’ or ‘Ltd’) https://www.gov.uk/running-a-limited-company/signs-stationery-and-promotional-material https://www.gov.uk/running-a-limited-company/signs-stationer...
- m4rc1e 3y ago
  Thanks for pointing this out. I've updated the site.
MAGZine 3y ago
This technology is useful for many industries. At PlanGrid, we built a version of this into all of our native platforms as well as into our web app. Allowing people to see what changed between pdf revisions was a priceless tool, even for less sophisticated users in the field. Rasterization is a must since pdfs otherwise are extremely inconsistent based on how they were generated and post-processed.
matricaria 3y ago
I’m going to check this out. Over the years in university, I accumulated different versions of PDFs with different annotations, because I tested various apps. It is very annoying to merge them manually.
epaga 3y ago
Very nice to have a native Mac app doing this! A related tool would be a cross-platform product the company I work for creates: i-net PDFC https://www.inetsoftware.de/products/pdf-content-comparer https://www.inetsoftware.de/products/pdf-content-comparer PDFC compares not only graphical differences but also detects content, columns, etc. We originally created it for ourselves because we weren't happy with any of the PDF comparison tools that were out there.
FirmwareBurner 3y ago
Any news on a Windows or Linux release?
- m4rc1e 3y ago
  I'm hoping to have a cross platform version in 2024 if time allows. I targeted Mac first because the major book publishers and designers use Macs.
ketanmaheshwari 3y ago
Slightly related, I recently discovered that `less` can read pdf files out of the box. Seems like it is working on Linux but not on macOS.
- e12e 3y ago
  MacOS comes with an old version of less (581.2) - as Apple fears and avoids GPL v3. Brew etc holds newer versions - but this particular issue probably has to do with missing lesspipe: https://github.com/wofr06/lesspipe#42-list-of-preprocessed-file-types https://github.com/wofr06/lesspipe#42-list-of-preprocessed-f...
- layer8 3y ago
  This is likely lesspipe.sh used via LESSOPEN. Less itself certainly doesn’t understand PDF, but it allows automatic custom preprocessing of its input, which many Linux distributions have preconfigured as the system default.
cubefox 3y ago
Suggestion: When highlighting text, you want to use "multiply" blend mode (a.k.a. subtractive color mixing) instead of opacity. Opacity makes black text lighter/greyish, which is not how physical text markers work, or colored sheets of transparent plastic.
- m4rc1e 3y ago
  I've just implemented user selectable blend modes. I've included the multiply mode as well. Thanks for your feedback.
  - cubefox 3y ago
    Cool!
- m4rc1e 3y ago
  Thanks for the suggestion. I plan on having user selectable blend modes. Currently, it's using the "difference" blend mode. This mode makes it easy to spot shifted images.
progfix 3y ago
The black and white mode doesn't look very useful. Check out how Autodesk is visualising changes. They use three colours: blue=only in first pdf, red=only in second pdf, black=in both pdfs. https://help.autodesk.com/view/BIM360D/ENU/?guid=GUID-08779B83-961E-4A6A-AC33-BC4B2DD0BCF7 https://help.autodesk.com/view/BIM360D/ENU/?guid=GUID-08779B...
yencabulator 3y ago
Open source & Linux alternatives: https://www.qtrac.eu/diffpdf-foss.html https://www.qtrac.eu/diffpdf-foss.html https://github.com/vslavik/diff-pdf https://github.com/vslavik/diff-pdf https://vslavik.github.io/diff-pdf/ https://vslavik.github.io/diff-pdf/

62 points by m4rc1e 3y ago

Mac app. They're looking for more beta testers.

Looks interesting! Just a heads up as you seem to be a UK registered limited company : >On business letters, order forms and websites, you must show: >the company’s registered number >its registered office address >where the company is registered (England and Wales, Scotland or Northern Ireland) >the fact that it’s a limited company (usually by spelling out the company’s full name including ‘Limited’ or ‘Ltd’) https://www.gov.uk/running-a-limited-company/signs-stationery-and-promotional-material https://www.gov.uk/running-a-limited-company/signs-stationer...

m4rc1e 3y ago
Thanks for pointing this out. I've updated the site.

MAGZine 3y ago

This technology is useful for many industries. At PlanGrid, we built a version of this into all of our native platforms as well as into our web app. Allowing people to see what changed between pdf revisions was a priceless tool, even for less sophisticated users in the field. Rasterization is a must since pdfs otherwise are extremely inconsistent based on how they were generated and post-processed.

matricaria 3y ago

I’m going to check this out. Over the years in university, I accumulated different versions of PDFs with different annotations, because I tested various apps. It is very annoying to merge them manually.

epaga 3y ago

Very nice to have a native Mac app doing this! A related tool would be a cross-platform product the company I work for creates: i-net PDFC https://www.inetsoftware.de/products/pdf-content-comparer https://www.inetsoftware.de/products/pdf-content-comparer PDFC compares not only graphical differences but also detects content, columns, etc. We originally created it for ourselves because we weren't happy with any of the PDF comparison tools that were out there.

FirmwareBurner 3y ago

Any news on a Windows or Linux release?

m4rc1e 3y ago
I'm hoping to have a cross platform version in 2024 if time allows. I targeted Mac first because the major book publishers and designers use Macs.

ketanmaheshwari 3y ago

Slightly related, I recently discovered that `less` can read pdf files out of the box. Seems like it is working on Linux but not on macOS.

e12e 3y ago
MacOS comes with an old version of less (581.2) - as Apple fears and avoids GPL v3. Brew etc holds newer versions - but this particular issue probably has to do with missing lesspipe: https://github.com/wofr06/lesspipe#42-list-of-preprocessed-file-types https://github.com/wofr06/lesspipe#42-list-of-preprocessed-f...
layer8 3y ago
This is likely lesspipe.sh used via LESSOPEN. Less itself certainly doesn’t understand PDF, but it allows automatic custom preprocessing of its input, which many Linux distributions have preconfigured as the system default.

cubefox 3y ago

Suggestion: When highlighting text, you want to use "multiply" blend mode (a.k.a. subtractive color mixing) instead of opacity. Opacity makes black text lighter/greyish, which is not how physical text markers work, or colored sheets of transparent plastic.

m4rc1e 3y ago
I've just implemented user selectable blend modes. I've included the multiply mode as well. Thanks for your feedback.
- cubefox 3y ago
  Cool!
m4rc1e 3y ago
Thanks for the suggestion. I plan on having user selectable blend modes. Currently, it's using the "difference" blend mode. This mode makes it easy to spot shifted images.

progfix 3y ago

The black and white mode doesn't look very useful. Check out how Autodesk is visualising changes. They use three colours: blue=only in first pdf, red=only in second pdf, black=in both pdfs. https://help.autodesk.com/view/BIM360D/ENU/?guid=GUID-08779B83-961E-4A6A-AC33-BC4B2DD0BCF7 https://help.autodesk.com/view/BIM360D/ENU/?guid=GUID-08779B...

yencabulator 3y ago

Open source & Linux alternatives: https://www.qtrac.eu/diffpdf-foss.html https://www.qtrac.eu/diffpdf-foss.html https://github.com/vslavik/diff-pdf https://github.com/vslavik/diff-pdf https://vslavik.github.io/diff-pdf/ https://vslavik.github.io/diff-pdf/