Aura HD Diferent font size in epub and kepub

[ersott]

Have you noticed it?, diferent font size in epub files and kepub?

In epub files size 2 are similar to size 5 in kepub files, using the same font.

My firmware are 3.1.1, thanks in advanced

[Nick Payne]

If I load a book as an epub and then as a kepub (using Calibre), for the same font size setting on the reader the screen font size is a lot smaller with the kepub. Aura HD also.

[ersott]

Thanks, is the same for me, i´m calm now ;-)

greetings.

[cybmole]

Originally Posted by Nick Payne

If I load a book as an epub and then as a kepub (using Calibre), for the same font size setting on the reader the screen font size is a lot smaller with the kepub. Aura HD also.

I am also seeing that - testing the extended driver plug in for the 1st time on Aura HD to send kepub formats from calibre

so is it a bug or a "feature" - so long as there's plenty of scope for moving font size slider further to the right it should not be an issue I guess ?

I have only tested with 1 book so far.

[GeoffR]

If the publisher doesn't specify a base font size in the book then it defaults to 12pt for epubs, 14pt for kepubs. I think it has always been like that.

Edit: Or is it 14pt for epubs and 16pt for kepubs? Something like that anyway.

[cybmole]

Originally Posted by GeoffR

If the publisher doesn't specify a base font size in the book then it defaults to 12pt for epubs, 14pt for kepubs. I think it has always been like that.

Edit: Or is it 14pt for epubs and 16pt for kepubs? Something like that anyway.

surely it should be the other way around - kepub appears smaller so should be a smaller points number than epub?

[cybmole]

update:
I am now a little confused as to how the 3 slider settings on the aura HD: font size, line space & margin - work for a mix of kepub & epub

what I think I am seeing is that the device only remembers 2 settings, a n epub setting and a kepub setting, and all books of the same type have the relevant settign applied when they are re-opened.

I had previously thought that these 3 slider settings were stored on a per-book basis- but it seems not ?

maybe they work per -book only if all books are same type ?
has anyone already puzzled this out. My previous experience was with sony e-readers they they did store a font size setting per book

[GeoffR]

Originally Posted by cybmole

surely it should be the other way around - kepub appears smaller so should be a smaller points number than epub?

If the base size is not set, then the default kepub font size should be a bit bigger than the default epub size. But if you are converting the book to kepub with Calibre then perhaps Calibre is setting the base font size for the kepub to a smaller size? (Have a look at the base font setting on the "look and feel" page of Calibre's conversion settings.)

[Anak]

Originally Posted by GeoffR

If the publisher doesn't specify a base font size in the book then it defaults to 12pt for epubs, 14pt for kepubs. I think it has always been like that.

Edit: Or is it 14pt for epubs and 16pt for kepubs? Something like that anyway.

Correct. The default font size has always been 14pt for kepub and 12pt for epub. The 14pt was (and still is?) hardcoded into the firmware.
This font size was also present in the kobo.css when it was still in use.

[cybmole]

Originally Posted by GeoffR

If the base size is not set, then the default kepub font size should be a bit bigger than the default epub size. But if you are converting the book to kepub with Calibre then perhaps Calibre is setting the base font size for the kepub to a smaller size? (Have a look at the base font setting on the "look and feel" page of Calibre's conversion settings.)

well whatever calibre does should be the same for both epub & kepub conversions ( I put new books through an epub to epub conversion routinely to standardise them) so I don't thank that explanation works - but it's no big deal - maybe I am misunderstanding the combo of slide position & base font size.

but as a thought experiment. lets imagine we create a new book, with paragraph font size set to 1em. & no other line height or font family settings in CSS.

run that through an epub to epub conversion to factor in any calibre settings.

Now disable the calibre kebub driver & send that book from calibre to aura HD so that it arrives as epub,

back in calibre, now disconnect aura, enable the kepub driver, reconnect aura, change the book title, & send it again so that it arrives under a new name & as a kepub.

On the aura HD ( with all sliders say at mid points ) open both books to same page. what differences would you expect to see - for font size, margin & line spacings ?

[GeoffR]

Originally Posted by cybmole

On the aura HD ( with all sliders say at mid points ) open both books to same page. what differences would you expect to see - for font size, margin & line spacings ?

Well keeping in mind that I don't have an AuraHD and I don't sideload kepubs, for a Kobo-bought kepub on my Glo I would expect the kepub font to be about 17% larger, the kepub margins to be roughly 5mm wider, and the line spacing to be the same (or very close anyway).

Edit: Here is a test to see of the problem is being caused by the kepub conversion: Try taking a plain DRM-free epub and copying it directly to the device (don't use Calibre) with two different file names: one with an .epub extension, and the other with a .kepub.epub extension. Then open each book without making any adjustment to the font settings between openings.

[cybmole]

Originally Posted by GeoffR

Well keeping in mind that I don't have an AuraHD and I don't sideload kepubs, for a Kobo-bought kepub on my Glo I would expect the kepub font to be about 17% larger, the kepub margins to be roughly 5mm wider, and the line spacing to be the same (or very close anyway).

That is what I thought you'd say, but I am seeing the opposite: in the kepub I see a smaller font & I have to compensate for that by moving the aura HD font size slider to the right

I am hoping that some kind person who does use calibre & does sideload both book types will post an explanation before I dig myself into a deeper logic hole.

[cybmole]

I will design and run a bunch of test if no one else has already done so.

A simple smart test would probably be to find a free public domain book in kobo store which can be downloaded in both formats, and then to run that same book through some extra calibre & plug in conversions so see where, if anywhere, the differences get introduced.

but does the store have PD books or other freebies in both epub & kepub formats , and can we trust the store books to be identically styled?.

I don't have my aura set up for direct store access, I've always use it offline, to avoid forced , unwanted, firmware changes.. anything I want to read on the device is sent via calibre, though I know how to drag n drop from windows if I have to eliminate calibre from a test.

bear in mind that technically , calibre only does to-epub conversions. the to-kepub trick is done by a extended driver plugin which tweaks the file name that is sent to the reader in order to trick the firmware - & maybe the plug-in also changes other stuff.

[GeoffR]

Here are the screenshots for this book from the Mobileread library: https://www.mobileread.com/forums/showthread.php?t=44226

I didn't use Calibre, I just copied the epub to the device, first with an .epub file extension, next with a .kepub.epub extension.

Both are open with exactly the same font settings: family=Georgia, size=31, lineHeight=0.88, margin=3

(Note that my Glo is running firmware 3.2.0 and is patched. The patch means that even though the font sliders are all at about the midpoint, the values they give at that midpoint will be different to an unpatched Glo. However the values are exactly the same for both books, so this shouldn't affect the relative size difference between books.)

[cybmole]

thanks for checking and posting that. but does your test not contradict was was said previously in the thread i.e. The default font size has always been 14pt for kepub and 12pt for epub.

unless on a device with sliders, the slider positions overrule those defaults ?

I think the test has to be with a non DRM book where it is also possible to view the CSS, it could be that the one you tested with has an explicit font-size setting encoded, which is overruling any slider positions ?

having said that though, I followed your link & if you are testing with the book " the widow Lerouge" - I don't see any font sizes in css within that book, when viewed with sigil.