Aura ONE Not rendered mathematical glyphs

[PenguinCEO]

故事主要描述當伐木

[jackie_w]

I think you need to find a better specialised font for mathematical symbols. EB Garamond contains very few glyphs from the unicode range 27C0-2BBF.

Using kepub rather than epub sometimes helps because it has the font fallback feature, but this is still no help at all if the Kobo's fallback fonts don't contain the missing glyphs either.

[PenguinCEO]

故事主要描述當伐木

[jackie_w]

Originally Posted by PenguinCEO

EB Garamond contains all the glyphs needed. But the contained glyphs are not rendered in the KA1. As you can see from the attached file.

I don't see how you have reached this conclusion. I opened your embedded copy of EBGaramond-Regular.ttf in the FontForge font editor. I'd estimate there are <10 glyphs present from your chosen unicode range.

What displays in the calibre Viewer on your PC/Mac and what displays on an ereader are two different things. I can't claim to understand all the calibre Viewer's technical details but I'd suspect it is looking for the missing glyphs from other fonts installed on your PC/Mac.

[PenguinCEO]

故事主要描述當伐木

[jackie_w]

It's more of a limitation than a bug. Full unicode fonts are very large and probably require a lot of memory. This is not a strength of eink readers. I suspect Kindle, Nook and other eink readers may have similar limitations. You can't please everyone. Their system fonts are targeted at 'the average user' not every specialist under the sun.

However, if you buy a retail maths epub I would have to hope that the publishers have embedded a suitable font (or possibly a subset of a font) which allows your book to be read properly on all epub reading devices.

If you're creating your own maths epub, just try Googling for a free maths font and experiment with it once it's embedded (or even just sideloaded to the Kobo fonts directory). Here's one you can try. It may not contain 100% of all possible maths glyphs but it should have better coverage than EBGaramond.

[RobertJSawyer]

Try downloading the Noto family of free fonts from Google. Noto is short for "No Tofu," and refers to the fact that they contain most/all Unicode glyphs, so you don't get tofu (a blank box or gibberish) when calling for a special character. Once downloaded, put them in a folder called "fonts" (no quotation marks, lowercase "f") beneath the root directory of your Kobo, and then select either Noto Serif or Noto Sans as the font to use with the ebook you are reading. If it works, then the problem is with Kobo's version of Garamond.

https://www.google.com/get/noto/

Also, Markus Dohle is the CEO of Penguin (my publisher); you might perhaps think twice about impersonating him.

[NiLuJe]

In point of fact, recent Kindle FW do bundle a large swath of the Noto font family (granted, the use-case there was South Asian scripts, but, still ;D) .

[jackie_w]

Guys,

Are you sure Noto is suitable for specialist maths purposes?

I have a copy of Noto Serif sideloaded on all my Kobos but it did not help with the OP's test epub. It was the first font I tried earlier today because I knew it contained a lot of less common glyphs. I discovered this from some extensive testing I did when trying to decide on a suitable font for displaying my Kobo custom English dictionaries with all the special glyphs used for pronunciation and word origin. Noto Serif worked very well for the dictionaries.

I should mention the caveat that my copy of Noto came from a customised version posted in these forums rather than direct from Google fonts. So there could be a difference in their glyph coverage.

[NiLuJe]

You might get better "esoteric" Unicode coverage from the Sans variant than the Serif one.

(Possibly stemming from the long history of Droid Sans).

I'll readily admit to not being sure how that actually applies to the problem at hand of mathematical symbols, though .

EDIT: Given the fact that mathematical symbols appear in the SMP and that Noto is BMP only, that's going to be a hard no .

Nothing in the Symbols variants, either, FWIW.

Time to dig up whatever font latex is using?

EDIT²: Give STIX a try?

[jackie_w]

Originally Posted by NiLuJe

EDIT²: Give STIX a try?

Well, yes, STIX is the one I linked to at the end of post #6

[NiLuJe]

@jackie_w: Oops? .

[DNSB]

Just to add my 2 cents worth to this discussion. EB Garamond does not contain the requisite glyphs as Fontforge shows exactly 9 glyphs (27E8, 27E9, 27EA, 27EB, 2A74, 2A75, 2A76, 2B45 and 2B46) in the 27C0-2BFF range though those characters don't display in the ebook. OTOH, I switch to a nameless Microsoft font or the freeware Code2000 font and the page displays rather nicely. See attached image.

The fault in our fonts... (may John Green forgive me).

Edit: Attached a zipped copy of code2000.ttf to the message. A bit of an ugly font but it does display almost the entire glyph set.

Edit2: Checked and the glyphs in code2000 only work up to 2B54 in the miscellaneous symbols and arrows area but then it was designed in 1998 with Unicode v2.x being the current version.