What are the downsides to enabling advanced for side loaded fonts?

[ZodWallop]

Kobo's software has gotten better and better over the years, like giving us the ability to turn header and footer on and off for kepubs.

At this point, the only patches I use are to enable ligatures in kepub and the 'Freedom to Advanced Font Controls'

Now, I understand that perhaps enabling ligatures by default makes things slower, judging by the options of optimizing speed or legibility (though I do wish ligatures were the default. They make the page look better).

But what are the potential downsides to Kobo giving advanced font control to all fonts, out of the box? It's not like Kobo makes money off of the built-in fonts.

I guess you could argue some sort of stability issues due to poorly built fonts. But that seems like it would be a danger inherent in the sideloading, rather than something that only becomes a problem once you can make finer adjustments.

Are there reasons I'm not seeing for restricting advanced font controls?

[jackie_w]

Originally Posted by ZodWallop

Are there reasons I'm not seeing for restricting advanced font controls?

If there are good reasons I'm not seeing them either

[ZodWallop]

Originally Posted by jackie_w

If there are good reasons I'm not seeing them either

Is there a way to request Kobo consider it in a future software update? (Aside from just hoping a Kobo employee trolls the board here?)

[MGlitch]

Originally Posted by ZodWallop

Is there a way to request Kobo consider it in a future software update? (Aside from just hoping a Kobo employee trolls the board here?)

There's a feedback option on Kobo's site, but most adblocks will hide it. It might not end up with the results you want, but I've used it to report bugs and they have been fixed. It certainly can't hurt and takes only a few minutes of your time. And it's much more likely to net you the change you want versus hoping someone from Kobo sees this thread and feels compelled to push it to whoever needs to see it.

[DNSB]

Originally Posted by ZodWallop

Is there a way to request Kobo consider it in a future software update? (Aside from just hoping a Kobo employee trolls the board here?)

At one point, I read a response from a Kobo employee to the effect that their fonts had customized tables and other fonts might not respond with good or decent results. I did run into one font that did not responds well to increasing the weight -- at least I didn't consider a font that started looking as if it was printed on a paper towel to be responding well. None of the other fonts I've played with showed this effect.

[ZodWallop]

Originally Posted by MGlitch

There's a feedback option on Kobo's site, but most adblocks will hide it. It might not end up with the results you want, but I've used it to report bugs and they have been fixed. It certainly can't hurt and takes only a few minutes of your time. And it's much more likely to net you the change you want versus hoping someone from Kobo sees this thread and feels compelled to push it to whoever needs to see it.

Thanks for that. I submitted feedback. I can only assume a team of Kobo engineers is on the project, planning to make my dream a reality.

[GeoffR]

If you side-load a font that has no bold variant, then the firmware generates a synthetic bold variant for use by the KePub reader. It seems inconsistent to allow that feature and not to allow the font weight slider to be used on the same font.

[GERGE]

Advanced font control deforms the type, that is the only downside I can speak about and only if you care about such things. That is why I prefer the editing the font files themselves when I am not happy with the weight of the type I am reading with. Using a different optical size might also help if you have access to them.

Ligatures patch used to work really ugly when justified. That is fixed now?

[ZodWallop]

Originally Posted by GERGE

Advanced font control deforms the type, that is the only downside I can speak about and only if you care about such things.

But even then, I assume it deforms the type on both pre-loaded and sideloaded fonts. So enabling advanced controls on sideloaded fonts doesn't seem like something that is suddenly going to cause a rash of complaints from customer that know enough to load a font themselves.

Ligatures patch used to work really ugly when justified. That is fixed now?

Not sure what you mean by 'ugly'. I do notice that justified Kepubs are far more likely to have widely spaced words than justified ePubs on my Nook.

Overall, I far prefer my Kobo. But in general, the Nook does a better job of page layout.

[Quoth]

Some fonts seem to be bad at smaller sizes, e.g. Dejavu Serif embedded looks like a different font below 5 on Kindle and just desired size on Kobo, one size up is fine. Georgia embedded from Linux in AZW3 or epub is fine at a small size, as is selecting a built in Georgia at a smaller size.

Some fonts copied direct via USB don't seem to work at all.

[lumpynose]

How do they know which character sequences to convert to a ligature? Are they assuming the standard ones, e.g., fl, fi, etc.? Some fonts have nonstandard ligatures, for example, I saw one that had a ligature for st where there was a connector at the top of the s going to the top of the t.

[the.Mtn.Man]

I suspect it's a simple matter that it would be impossible for Kobo to guarantee that every font a user might install will work with "Advanced Font Controls", and so to avoid complaints and support calls, they simply disable it for side-loaded fonts.

[DNSB]

Originally Posted by lumpynose

How do they know which character sequences to convert to a ligature? Are they assuming the standard ones, e.g., fl, fi, etc.? Some fonts have nonstandard ligatures, for example, I saw one that had a ligature for st where there was a connector at the top of the s going to the top of the t.

If the font is correctly compiled, there will be a ligature substitution table inside the GSUB table. This can be read to find which ligatures the font supports. In the st ligature you mentioned, it should be found in the substitution table (Libertine does have this table and ligature).

As for what constitutes a "standard" ligature? That is more of a religious argument than anything else. There have been many ligatures used in typography over the centuries. For instance, a lower case f followed by a full stop has a ligature in some fonts. Other arguments would involve such words as selfless where the fl ligature should not be used as it crosses the boundary between self and less (morpheme boundary).

[lumpynose]

Originally Posted by DNSB

If the font is correctly compiled, there will be a ligature substitution table inside the GSUB table.

Thanks. That was what I was guessing / hoping for; something logical.

[GeoffR]

Originally Posted by the.Mtn.Man

I suspect it's a simple matter that it would be impossible for Kobo to guarantee that every font a user might install will work with "Advanced Font Controls", and so to avoid complaints and support calls, they simply disable it for side-loaded fonts.

Of course it is impossible for Kobo to guarantee anything about side-loaded fonts or books, but in this case, enabling the feature even without a guarantee could actually reduce the number of calls to support:

At the moment with side-loaded fonts the Advanced features fail 100% of the time, because they are disabled, which must generate some calls to support. If they were enabled they would fail less than 100% of the time, and so some of those calls wouldn't be required.

If they enabled the feature and added a little note on the Advanced menu when adjusting a side-loaded font along the lones of "Warning: features on this menu might not work properly. with this side-loaded font." then they could reduce the number of calls to support even further.

(Edit: In practice, the patch that enables the Advanced features for side-loaded fonts only fails for .OTF fonts in the ePub reader. I don't think I have ever come across a .TTF font where it fails. So even if Kobo just enabled the Advanced features for side-loaded .TTF fonts that would make things much better for its customers and certainly reduce the number of calls to support about why the Advanced menu is not available, without causing Kobo any additional problems.)