Quote:
Originally Posted by jo_by
Kia ora,
I am new to ePub. I'm a graphic designer with some rudimentary html skills, but definitely flying blind in terms of fiddling with code. So much so that I don't really know where to put this question, so sorry if it's in the wrong place.
I have been working on a fixed layout ePub for a design journal. (I should note here that yes, it does need to be fixed not reflowable as it contains several visual essays where the authors have specific requirements around layout – my preference would have been for it to be web-based or in a native app, but that isn't my call  ).
It was produced in InDesign and is generally working well. I ended up finding Calibre as I needed a way to resize a heap of pngs that InDesign generated for visual elements like text underlines and overrules – these were causing a problem with vendor platforms as though they are tiny in kb terms, the dimensions of some of them exceeded 4 million pixels. What a headache.
Anyway I worked through that, and now have a single error:
ERROR ITMS-9000: Invalid prefix attribute in root (package) element of the OPF file. Please supply a prefix attribute with valid rendition value in root <package> element of the OPF file
I found the OPF file in 'edit file' and the package bit reads:
<package xmlns="http://www.idpf.org/2007/opf" version="3.0" unique-identifier="bookid" prefix="ibooks: http://vocabulary.itunes.apple.com/r...xtensions-1.0/ calibre: https://calibre-ebook.com">
I tried to swap this out for content from an OPF file where this error was not occurring (but the image issue persisted), and saving it:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<package version="3.0" xmlns="http://www.idpf.org/2007/opf" unique-identifier="bookid" prefix="rendition: http://www.idpf.org/vocab/rendition/# ibooks: http://vocabulary.itunes.apple.com/rdf/ibooks/vocabulary-extensions-1.0/">
But when I reopen the editor, it looks like Calibre strips that out and reverts it to the original.
Any suggestions about what's wrong with that package element? (I have no idea what a prefix attribute is or what is should look like!) And how can I maintain the changes that Calibre seems to want to remove?
Any advice appreciated, especially if it's basic enough for my non-expert skills!
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I gotta ask--maybe there's something we can think of, but what sort of design element like an hr or overrule, etc., would actually take up >
4M pixels? If these images are huge in the package links folder (I see this horrifyingly often, with designers that never work in digital), have you considered simply resizing those graphics, in the original package file, so that they aren't bigger than they
need to be, so that they export smaller, not violating Apple's MPx limits?
I see .tiff files, for example, that are well over 100MB, themselves, some piece of art, that's going to be half-a-page in size, in the print book. I see this sort of cruft all the time.
Any chance that these graphic elements are like that?
In terms of changing out the package, Calibre IS going to replace that, simply because you are opening the editor. Try editing it in a regular HTML/text editor, not software like Calibre or Sigil that's part of a software package/program/app that looks to "fix" things for people.
Hitch