Would stitching all the images together into a single continuous image before comparison be better? I mean you would trade off memory but would you not avoid page break errors?
Show HN: PDF-Diff - Visualize any differences between two PDFs
31–37 of 37 posts
Re: Show HN: PDF-Diff - Visualize any differences between two PDFs
#32Would stitching all the images together into a single continuous image before comparison be better? I mean you would trade off memory but would you not avoid page break errors?
Probably. It's really similar to the approach that munificentbob used in his tool (http://journal.stuffwithstuff.com/2021/07/29/640-pages-in-15...). It uses mainly a Photoshop action.
Re: Show HN: PDF-Diff - Visualize any differences between two PDFs
#33Would stitching all the images together into a single continuous image before comparison be better? I mean you would trade off memory but would you not avoid page break errors?
Probably. It's really similar to the approach that munificentbob used in his tool ( http://journal.stuffwithstuff.com/2021/07/29/640-pages-in-15... ). It uses mainly a Photoshop action.
This approach would be pretty cool for a bunch of file formats as long as you can rasterize them
Re: Show HN: PDF-Diff - Visualize any differences between two PDFs
#34I made a PDF diff tool for myself for one of my internships >10 years ago. One of my responsibilities was to get sign-off on any changes engineers made to schematics. (It was a really bad internship! I ended up automating a bunch of stuff for them because my actual job was mind-numbingly boring.) After the first few times comparing PDFs of schematics by eye, I said screw it and wrote a tool to export to PNGs and then…
Rasterization prior to comparison is a really clever idea. Doing this with PDF spec code would be an absolute nightmare. Checking 2 bitmaps for equality is just a few lines of code. Many times, you aren't really concerned with the specific differences being described natively. You just want to know if a human would perceive differences between 2 copies of the "same" form.
I wrote a tool to do this for circuit board artwork changes. It used gerbv to rasterize the vector (gerber) files, then used XOR on the pixels to make unchanged areas disappear. For such a simple tool it is quite useful.
Re: Show HN: PDF-Diff - Visualize any differences between two PDFs
#35I just use Beyond Compare from Scooter Software. Best program ever. Been using it for 20 years now. I swear by it as an evangelist user. Diff images, Excel documents, PDFs, whatever.
> Diff images, Excel documents, PDF
I'm also a big fan and user of Beyond Compare, but I had no idea that it can also compare those files. The above file options are also not there in the app, especially I was looking for pdf.
Re: Show HN: PDF-Diff - Visualize any differences between two PDFs
#36Kasyan Servetsky created a script[1] to compare two documents using a similar technique within InDesign, no intermediate export necessary. It overlays one on top of the other using the Difference blend mode. Quite resource intensive, so only useful depending on the particular document and machine you do this with.
[1]: http://kasyan.ho.ua/indesign/all/compare_two_documents.html
Re: Show HN: PDF-Diff - Visualize any differences between two PDFs
#37Kasyan Servetsky created a script[1] to compare two documents using a similar technique within InDesign, no intermediate export necessary. It overlays one on top of the other using the Difference blend mode. Quite resource intensive, so only useful depending on the particular document and machine you do this with. [1]: http://kasyan.ho.ua/indesign/all/compare_two_documents.html
Really similar to one I have already seen on Photoshop. My goal was comparing the pdfs without any Adobe, my editors do not have license for that.