Alternate glyph support (font-variant-alternates)

[momoha]

Hello everyone,

Does anyone know if the CSS font-variant-alternates is supported in ePub3? I tried in Sigil and it doesn’t seem to be working, and I can’t seem to find any information about it for ePubs.

I have a book where alternate glyphs are used for certain letters, so if that doesn’t work, I’ll have to turn them into images I guess.

Any information or ideas would be of great help
Thanks!

[DNSB]

As far as I am aware, font-variant-alternates is part of the supported CSS for epub3. It does require use of an OpenType font that supports features such as 'historical-forms' which is a pretty limited set. Equally sadly, font-variant-alternates is not supported by most renderers. Pretty much a useless feature.

[JSWolf]

Originally Posted by momoha

Hello everyone,

Does anyone know if the CSS font-variant-alternates is supported in ePub3? I tried in Sigil and it doesn’t seem to be working, and I can’t seem to find any information about it for ePubs.

I have a book where alternate glyphs are used for certain letters, so if that doesn’t work, I’ll have to turn them into images I guess.

Any information or ideas would be of great help
Thanks!

Don't use images where you don't have to. What you could do is embed a font that has glyphs you need. But before you do, make sure the font has enough weight for eInk.

The image based solution would only be needed for Mobi on an old Kindle if the font doesn't have the glyphs/. So if you can get access to an old Kindle or ask on MR if someone has such can test some words for you, then you'll know if you need the images or not.

[Tex2002ans]

Originally Posted by momoha

Does anyone know if the CSS font-variant-alternates is supported in ePub3?

According to Mozilla's site:

https://developer.mozilla.org/en-US/...ant-alternates

it's only supported in Firefox currently.

Originally Posted by momoha

I have a book where alternate glyphs are used for certain letters, so if that doesn’t work, I’ll have to turn them into images I guess.

What's the use-case? Can you show example text of what you're trying to achieve?

[momoha]

I’m converting a children book into fixed-layout. The printed book is using the font Bree with the alternates glyphs for the letters « Q » and « v » as the default ones are a bit hard to read.

If font-variant-alternates is supposed to be supported, I’d love to try this out first as it’d be the best option, but I’m unable to make the code work. I even tried outside of ePub and it’s just not working. InDesign is telling me that the alternates are in the salt group, all the code seems right, but, nothing... I,m stuck

I joined my test ePub, maybe one of you know how to solve this?

[Doitsu]

Originally Posted by momoha

I joined my test ePub, maybe one of you know how to solve this?

You could try using Fontsquirrel's Webfont Generator in expert mode and flatten the font.

[JSWolf]

Originally Posted by momoha

I’m converting a children book into fixed-layout. The printed book is using the font Bree with the alternates glyphs for the letters « Q » and « v » as the default ones are a bit hard to read.

If font-variant-alternates is supposed to be supported, I’d love to try this out first as it’d be the best option, but I’m unable to make the code work. I even tried outside of ePub and it’s just not working. InDesign is telling me that the alternates are in the salt group, all the code seems right, but, nothing... I,m stuck

I joined my test ePub, maybe one of you know how to solve this?

Why is it OK to use this font for the print version and not the eBook?

[momoha]

Well, I found a bypass solution which worked but is pretty messy, I wouldn’t recommend that to anyone... I edited the font using FontForge and replaced the normal letters with their alternate glyphs

I really wish I could figure out how to make the font-variant-alternates work though.

Originally Posted by JSWolf

Why is it OK to use this font for the print version and not the eBook?

In the print version, alternate glyphs are used, which I am unable to reproduce in the ePub. Alternate glyph means both letters are attributed to the same unicode. So in the print version, instead of using the regular « Q » and « v », it is the alternate ones that are used. Only some rare fonts have alternate glyphs (like the famous Zapfino) and this function is really not widely used, except for ligatures I believe.

[momoha]

Originally Posted by Doitsu

You could try using Fontsquirrel's Webfont Generator in expert mode and flatten the font.

I just tried and it does work at overwriting the regular glyphs with the alternate ones, which solves my problem at the moment, but not for potentiel future cases where a book would be using both glyphs, regular and alternate.

So, well, I still wish to make that font-variant-alternates work hehe

[JSWolf]

Originally Posted by momoha

I just tried and it does work at overwriting the regular glyphs with the alternate ones, which solves my problem at the moment, but not for potentiel future cases where a book would be using both glyphs, regular and alternate.

So, well, I still wish to make that font-variant-alternates work hehe

One thing you should never ever do is replace a different character with the alternates and use that. Some programs/devices allow the embedded font to be replaced or not used.

[Tex2002ans]

Originally Posted by JSWolf

One thing you should never ever do is replace a different character with the alternates and use that. Some programs/devices allow the embedded font to be replaced or not used.

It's not a different character, it's an alternate form.

It's not like some of those dingbat/foreign fonts that replaced "abcd" with absolutely different symbols "αβγδ".

It's substituting a swashy 'Q' with a normal 'Q'. Or 'a' with a more rounded 'a' (as a child would write [see GIF below]):

https://helpx.adobe.com/content/dam/...n-type-bar.gif
https://helpx.adobe.com/illustrator/...haracters.html

Before: https://ilovetypography.com/OpenType/_img/salt_src.gif
After: https://ilovetypography.com/OpenType/_img/salt_trgt.gif

I would agree with Doitsu, your best best would probably be to flip the alternate symbol in the font itself, then embed that modified font into the Fixed Format Ebook. Currently, that advanced CSS3 is just not well supported across readers/browsers.

Side Note: If you look at the font OP mentioned, the 'v' looks a lot like a 'u', and in a children's book, I could see how that would be extremely confusing.

Originally Posted by momoha

[...] which solves my problem at the moment, but not for potentiel future cases where a book would be using both glyphs, regular and alternate.

I can't think off the top of my head where you would require both... besides Maths. Are you thinking of things like the swashy Q, where it only applies in the beginning of a word? Or in special ligatures like "Qu"?

Anyway, it all stems back to a problem of reader support:

• Embedded fonts are already an issue
  • Can't guarantee device supports even that.
• Advanced CSS3 support is nearly non-existent in ebooks
  • If it's not supported in browsers, there's 99.9% chance it won't work in books.
• and Fixed Format is just a plain disaster.

If you created a book which relied on alternate characters for comprehension, you most likely have serious underlying issues in your text.

[roger64]

Hi

Is this necro-posting?

It's still about the CSS property font-variant-alternates to be used in an ePub3.
My OT font is Linux Libertine. I'd like to write in the CSS at the body place, the following line:

font-variant-alternates: stylistic ();

Question: I do not know how to fill-up what must be inserted within the red brackets. In the text of the ePub, I'd like to make appear the alternate character instead of &

My font has the stylistic set ss06 (see screenshot). Currently, I can make appear the alternate character only using the smcp set as you can see (other screenshot), but then I have to wrap a span around each & which is not very convenient.

I'm afraid I have not been clear...

[Doitsu]

Originally Posted by roger64

It's still about the CSS property font-variant-alternates to be used in an ePub3.

AFAIK, font-variant-alternates isn't widely supported. However, font-feature-settings works fine with ADE 4.5:

body {
    font-family: 'Linux Libertine';
    
    -moz-font-feature-settings: "salt";
    -webkit-font-feature-settings: "salt";
    font-feature-settings: "salt";
}

[roger64]

font-feature-settings: "salt";

It indeed does work, but it also modifies some other letters (for example I get a strange h with a tail). So, I can't use it for the body.

It would be convenient for a span around the &, but then I would not be any better than the smcp solution.

[JSWolf]

Originally Posted by Doitsu

AFAIK, font-variant-alternates isn't widely supported. However, font-feature-settings works fine with ADE 4.5:

body {
    font-family: 'Linux Libertine';
    
    -moz-font-feature-settings: "salt";
    -webkit-font-feature-settings: "salt";
    font-feature-settings: "salt";
}

But it doesn't work with ADE 2.0.1 or even ADE 3.x. So it's not a good idea to use it as a lot of Readers or programs with RMSDK are not using the latest version and thus do not support such.