Quote:
Originally Posted by Quoth
And you really don't want to see what inside a real, not a scan, PDF based on postscript for the text and locations of the text and vector images. Also unlike real ebooks based on HTML the innards need not at all be sequential. PDF is a sort of wrapper with multiple layers and kinds of things in it. The epub 3 fixed layout is sequential and is sort of human readable.
Postscript is a programming language
Text can be generated by a program fragment or included as a stream.
PDFs can have postscript content that's only easily understood by executing the program.
Actual postscript not inside a PDF does a bit more
https://paulbourke.net/dataformats/postscript/ |
Quote:
Originally Posted by Quoth
And as far as I can figure out, they only do this so it can use Amazon DRM instead of Adobe DRM. Because Kindles can do actual DRM free PDFs just as badly.
They did use Adobe DRM before they bought mobipocket or did azw (before azw3) or before the first Kindle. But you pay Adobe a royalty.
Also very long ago the DRM on PDFs was 'broken'. Still trival to save a password free version of a password protected PDF.
A company asked me once to develop a way of having a secure PDF for public download rather than their 'watermark'. I explained that such a thing is fantasy.
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Yup, agreed on all fronts.
Hitch