Reader HTML/CSS bug lists

nabsltd · 07-13-2017, 03:47 PM

I'm looking at a variety of new reader options, with out-of-the-box EPUB support being #1, so Kindle is out. Other than that, though, what I care most about is the ability to display a book correctly.

Currently, I have an Onyx Boox M92, and the best reader available for it is a fairly ancient version of Cool Reader, and even some basic HTML/CSS features are either not implemented at all (like borders and "height"), or are quite buggy (like "line-height" or "<br />" handling). So, I have to do a lot of editing of ebooks before they are readable on the M92, and I'd like to cut that time down.

In addition, though, there are some newer HTML/CSS features that I find really either make the book look a lot better (like "float" for initial caps, or OpenType small caps), or help make otherwise hard-to-create layouts easy (like background images), so I'd like to be able to use them if possible.

So, has anybody compiled (and maintained for current versions) any kind of HTML/CSS errata lists for both proprietary readers (like those built-in to Kobo devices) and ones that support multiple devices (like Android readers, etc.)?

For reader apps I can get for free to test (like most of the Android apps), I'll probably do my own testing anyway, but if somebody else has already started, that would make my work a bit easier.

JSWolf · 07-18-2017, 04:30 PM

Cool Reader is a rather poor reading app. If the M92 is using Cool Reader to handle ePub, then yes, you do may very well want a different Reader..

The standard to which commercial ePub is measured is is ADE which is what Kobo Readers use. I have an H2O and I've very nice. It works very well with ePub. You don't have to edit ePub so much to use on a Kobo Reader. And the screen is nicer because it's a Carta screen.

nabsltd · 07-20-2017, 01:43 AM

Quote:

Originally Posted by JSWolf

Cool Reader is a rather poor reading app. If the M92 is using Cool Reader to handle ePub, then yes, you do may very well want a different Reader..

I don't expect any new reader hardware to be stuck with something that old, but it was an example of where I am now.

Quote:

The standard to which commercial ePub is measured is is ADE which is what Kobo Readers use.

Kobo's non-KePub reader uses RMSDK, which is not ADE. RMSDK is a toolkit for creating an ebook reader, and every reader app that uses it has been heavily customized, and has different bugs in the HTML/CSS rendering.

In fact, the latest version of Adobe Digital Editions (4.5) has numerous bugs in HTML/CSS rendering. One quick example is that "page-break-before: always" plus a full-page image seems to always result in an extra blank page before that page. Sure, not a big deal, but there are also some that are huge, like the two attached files, showing Calibre reader and ADE 4.5 with the same 2 paragraphs from the same ePub (which also works perfectly on the brain-dead Cool Reader on the M92). And, Flight Crew validates that ePub with no errors, so it's ADE, not the ePub.

On the other hand, because ADE doesn't allow base font selection, base line spacing, "installing" of fonts, etc., there are a lot of bugs it doesn't have that exist on readers that use RMSDK on proprietary devices. Add in all the various versions of RMSDK in use in these apps, and you really have no way of knowing if valid HTML and CSS will result in a perfect display, something readable but not 100% accurate, or something unreadable.

I have yet to find a reader app that doesn't have at least one critical HTML/CSS bug (i.e., one that causes you to not be able to read the text at all), although Calibre's reader is still the best overall for these critical ones (so far, only a bug in "float" handling that can move the float to the next page), but even it has a few annoying ones, like treating "word—" (which is "word" followed by an em-dash) like it is proper to break a line between the "d" and the em-dash.

JSWolf · 07-20-2017, 05:51 AM

RMDSK is the code behind ADE. Kobo's implementation of RMDSK does allow installing fonts, it has line height and margin adjustments. It also has many more fonts sizes than most Readers.

I cannot speak for what's up with ADE 4.5 as I refuse to install it due to the new DRM. I'm on 2.0.1 and I'm also using whatever Kobo supplies. I've not seen an issue with Kobo with incorrect rendering when reading ePub. So please don't compare ADE 4.5 to whatever version RMDSk that Kobo is using.

If you attach a text ePub that shows that issue with ADE 4.5, I can try it on my H2O and see what happens.

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07-13-2017, 03:47 PM	#1
nabsltd Evangelist Posts: 417 Karma: 6913952 Join Date: Aug 2013 Location: Hamden, CT Device: Kindle Paperwhite (11th gen), Scribe	Reader HTML/CSS bug lists I'm looking at a variety of new reader options, with out-of-the-box EPUB support being #1, so Kindle is out. Other than that, though, what I care most about is the ability to display a book correctly. Currently, I have an Onyx Boox M92, and the best reader available for it is a fairly ancient version of Cool Reader, and even some basic HTML/CSS features are either not implemented at all (like borders and "height"), or are quite buggy (like "line-height" or "<br />" handling). So, I have to do a lot of editing of ebooks before they are readable on the M92, and I'd like to cut that time down. In addition, though, there are some newer HTML/CSS features that I find really either make the book look a lot better (like "float" for initial caps, or OpenType small caps), or help make otherwise hard-to-create layouts easy (like background images), so I'd like to be able to use them if possible. So, has anybody compiled (and maintained for current versions) any kind of HTML/CSS errata lists for both proprietary readers (like those built-in to Kobo devices) and ones that support multiple devices (like Android readers, etc.)? For reader apps I can get for free to test (like most of the Android apps), I'll probably do my own testing anyway, but if somebody else has already started, that would make my work a bit easier.

07-18-2017, 04:30 PM	#2
JSWolf Resident Curmudgeon Posts: 73,957 Karma: 128903250 Join Date: Nov 2006 Location: Roslindale, Massachusetts Device: Kobo Libra 2, Kobo Aura H2O, PRS-650, PRS-T1, nook STR, PW3	Cool Reader is a rather poor reading app. If the M92 is using Cool Reader to handle ePub, then yes, you do may very well want a different Reader.. The standard to which commercial ePub is measured is is ADE which is what Kobo Readers use. I have an H2O and I've very nice. It works very well with ePub. You don't have to edit ePub so much to use on a Kobo Reader. And the screen is nicer because it's a Carta screen.

07-20-2017, 05:51 AM	#4
JSWolf Resident Curmudgeon Posts: 73,957 Karma: 128903250 Join Date: Nov 2006 Location: Roslindale, Massachusetts Device: Kobo Libra 2, Kobo Aura H2O, PRS-650, PRS-T1, nook STR, PW3	RMDSK is the code behind ADE. Kobo's implementation of RMDSK does allow installing fonts, it has line height and margin adjustments. It also has many more fonts sizes than most Readers. I cannot speak for what's up with ADE 4.5 as I refuse to install it due to the new DRM. I'm on 2.0.1 and I'm also using whatever Kobo supplies. I've not seen an issue with Kobo with incorrect rendering when reading ePub. So please don't compare ADE 4.5 to whatever version RMDSk that Kobo is using. If you attach a text ePub that shows that issue with ADE 4.5, I can try it on my H2O and see what happens.

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