Useful information from Rayek Elfin on the InDesign forums, a year ago. My discovering an answer to the question: ‘do the ePub 3 specs officially support animated .PNG files?’ was like prising blood from a stone. But at least I confirmed that, according to Elfin, “fixed ePubs” output from InDesign can support .APNG in output…
I use APNG (Animated PNG) files. These are supported in fixed ePubs and also work when published online. The trick is to change the [InDesign] Export options (Object–>Object Export Options) to “Use Existing Image for Graphic Objects”. This is really the best option anyway with any imported bitmap: InDesign’s image optimization is well below par, and an additional advantage is the very fast ePub preview (because InDesign no longer re-compresses your images again and again… and again!). […] just drag and drop them in your InDesign file. No need for masking in this case, because APNGs support the full range of transparency. Don’t forget to tell InDesign to use your APNG files (see above export options) otherwise only static images will be generated.
Can it really be that easy to do an animated magazine? But of course the problem is the sorry lack of desktop reader software support for both i) the fixed layout format and ii) the user controls needed to control / replay the animation.
* Until recently the currently-developed Thorium Reader was the only fixed ePub reader I know that can handle animations in an .ePUB file. Still updating, I see. But even with the latest version it’s too clunky compared to Sumatra PDF, and the rendering of small type leaves a lot to be desired.
* Adobe Digital Editions supposedly opens fixed .ePub, but still it totally fails to open them, even four of my various test files from its own InDesign software. And is generally clunky and feels very old. Some of the guys at Adobe must be writhing with embarrassment at having to push out this junk. Uninstalled. Again.
* No movement by the best PDF reader, Sumatra, to support fixed ePub and animations. Though it nicely handles reflowable .ePub files.
* A genuine freeware contender, found. Azardi actually works. Now in version 43 (though the file label shows “2.0”), nine languages supported, seemingly last updated circa 2016. Opening/launching speed is fine. Page-turn could be a touch faster. It displays small fonts far better than Thorium. Supports .PNG animation! Not bad, not bad at all… though it always open an .ePub from Windows Explorer with a dark background for the pages and needs to be adjusted. That’s only a few clicks of a prominent button, but it’s annoying. Also, it appears it’s fixed width only. It can do nothing at all with reflowable .ePUB files, not even open them. Also, it triggered a virus alert! These three problems would make it very difficult to foist on magazine readers and say “you have to use this”.
So, there’s still no ideal solution, and it’s the lack of a good reader that’s holding everything up. Such as waste… all that effort put into .ePUB and there’s not one decent reader software that can display its fixed-format magazines in a nice way on a desktop PC. People who want to make children’s talking books also have the same lack-of-readers problem with audio embedding.
Update: After way too much searching, some more supposedly Windows desktop fixed-layout ePub readers.
* Lektz Reader. Old, circa 2016. Claims to support fixed layout. Installed with the .exe fixed to launch with Administrator rights in Windows, and it proved impossible to remove this right. Very unusual behaviour, I’ve never seen that before in Windows. Uninstalled without launching, due to a possible security risk.
* Okular. A supposedly “Universal Document Viewer”, which turns out to only support ePub via an integration of the old “ebook-tools” open source suite. Again, that code was last updated in 2012/2016. 2016 seems to be when most fixed .ePUB development stopped. Several comments on Reddit to the effect that Okular is iffy for anything other than reflowable ePubs. Not tried.
* Koodo reader. Tried the Portable. Complete and utter failure to render fonts — yet Thorium can handle them. No good, deleted.
* Apple Books. Is there a Windows desktop version? No, it seems not. But Apple has security freak-outs about so much these days, that apparently it’s all too easy to find bits of one’s magazine content blocked.