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A comment on Show HN: PDF-Diff - Visualize any differences between two PDFs. Parent comment

Re:Show HN: PDF-Diff - Visualize any differences between two... by bob1029 on Saturday August 06, 2022 @09:46AM (#32368034)
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.

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Re:Show HN: PDF-Diff - Visualize any differences between two... by markrages on Saturday August 06, 2022 @04:00PM (#32371074)
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.
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