Some Kerning Issues...

[svkytbsld]

I hope I can explain my point...

I am a bit obsessive about kerning. I use fonts with kerning and if needed, I do corrections by hand on FontForge. But no matter how much I work on it, I can't get the perfect result with KOReader. (Device: Inkpad 3)

For example, take the word "mining". In principle, there has to be equal metrical and optical distance between first 4 letter: "m-i-n-i-n". When I use famous fonts with well-tuned kerning like EB Garamond, Adobe Garamond Pro, Minion Pro, etc., KOReader displays it like, let's say, "m--i-n-i-n" at relatively normal sizes (17-19). I got used to such kind of asymmetries, so I do kerning by hand and try to decrease the distance between first two letter "m--i" by incrementally decreasing the kern value. After 3-4 try, it seems I can decrease it ON COMPUTER SCREEN. But when I export the font to KOReader, I get absurd results like, for example, "mi-n-i-n". I hope you got the point.

Besides, even PDFs of which typesetting are carefully designed for imprint show kerning issues on KOReader, even if they are tiny... So, problem is not related only for EPUBs, I guess

OK, I have to admit that it may be the best app and I really like it. But I am trying to do some fine-tuning typesetting and my standard is high.

So, here are my questions:

1) Even if we work hard and in detail, is it not possible to get perfect, print-like kerning results on on ereaders' screen? Am I digging an impossible hole?

2) If it is possible, do you know the way?

3) If don't, could developers please work on kerning feature of KOReader more?


Regards,

[NiLuJe]

We're going to need way more details about exactly what you're tweaking, which version of FontForge you're using, and how you're generating your font, because I have seen numerous cases of FF fucking up the kerning tables on export in strange and interesting ways .

(This means this might be something best done with a redistributable font, and a specific testcase).

Do make sure you haven't changed the kerning mode from its default (which should be "best"), as anything else won't deal with modern kerning tables properly.

That's for ePubs, for PDFs, if you're not enabling reflow (and you shouldn't), we have no further control over how stuff gets rendered (and I'm unfamiliar with MuPDF's handling of typography rules).

[NiLuJe]

Also, whatever you use to check your tweaks before it hits your device should *NOT* be using subpixel positioning (nor rendering, good old grayscale AA only) to have a better chance of matching what it will ultimately look like in CRe.