Unwanted ligature feature added to fonts, not good

[Luc(as)]

Type abcdefhijklm in a monospaced font, Courier, Consolas etc. The letters i and j are combined into the Dutch digraph/diphthong "ij", which is a letter with its own pronunciation, it is not a ligature. (It might look like one though, many fonts have a special shape in dlig.) Monospaced fonts do not have a ligature feature on purpose, inventing and activating a wrong ligature changes text lengths. Please stick to the OpenType features of the font.
(observed in Affinity Designer Beta 2.5.0.2415)

In the screenshot, Courier with the letters ij occupying the same with as any other character. In the (magnificent) Typography window, the font seems to have a Ligature feature.

[Alfred]

1 hour ago, Luc(as) said:

The letters i and j are combined into the Dutch digraph/diphthong "ij", which is a letter with its own pronunciation, it is not a ligature.

There seems to be some debate about this. From https://en.wikipedia.org/wiki/IJ_(digraph)#Status:

Quote

As the rules of usage for the IJ differ from those that apply to the many other digraphs in the Dutch language—in some situations behaving more as a single ligature or letter than a digraph—the IJ is not only confusing to foreigners, but also a source of discussion among native speakers of Dutch. Its actual usage in the Netherlands and in Flanders (Belgium) sometimes differs from the official recommendations.

As I understand it, in orthographic terms “ij” is a digraph, but a ligature is a purely presentational form.

[walt.farrell]

1 hour ago, Luc(as) said:

In the screenshot, Courier with the letters ij occupying the same with as any other character. In the (magnificent) Typography window, the font seems to have a Ligature feature.

You can turn off the Standard Ligatures and avoid that happening.

There is some debate in the forums about whether Affinity applications should have Standard Ligatures on by default, but they do. So if you don't want those ligatures you need to disable the function at this point.

[Luc(as)]

Hi Walt,

It is obvious that I can turn off Standard Ligatures. It should also be obvious that Standard Ligatures must be ON by default in all applications, because that is the recommended implementation from the OpenType spec.

But this is a totally different problem, sorry if I have not made myself clear, I will try again.

When a font has a "liga" feature, it should be active. The fonts I mentioned (monospaced and coding fonts) do NOT have a "liga" feature. And then Affinity is inventing and activating its own "liga" feature, which is NOT in the font. And it does it with the characters "ij" that should NOT even be treated as a Standard Ligature.

That is simply a very stupid bug that must be fixed as soon as possible, no debate needed 🙂

[kenmcd]

There are no Standard Ligatures (liga) at all in Courier New for Latin text (only for Arabic).
And Affinity is adding more than just ij (see image below).
A font designer may be leaving these out of Standard Ligatures for a reason.
A user may want a font designed like that for a reason.
This is unwanted "help" in those cases.

 

Note: this conversion to single characters is also carrying over into PDFs (and should not be).

[walt.farrell]

On 5/3/2024 at 2:18 PM, kenmcd said:

And Affinity is adding more than just ij (see image below).

According to FontCreator, the characters you show are part of Courier New:

and

But I'm not seeing an indication that they are marked as standard ligatures. (I am, however, not very skilled at using FontCreator yet.)

[kenmcd]

1 hour ago, walt.farrell said:

But I'm not seeing an indication that they are marked as standard ligatures. (I am, however, not very skilled at using FontCreator yet.)

No, they are not OpenType Standard Ligatures in this font. So they should not be being converted from two characters into a single character. That is the point.

Those legacy single-character ligatures are old pre-Unicode characters which got grandfathered into their own Unicode code points. There is only about nine of them in Latin script plus the digraphs. Most OpenType ligatures have no single-character replacement with a code point - it is just these few legacy exceptions (unless they are assigned code points up in the PUC - rare).

Some font designers actually leave these legacy ligature characters out of the font to avoid nonsense like this. But then users may have issues with importing or pasting text which includes these old characters. So having them is just insurance. Some designers remove these old characters (code points) but do include those ligatures in OpenType Standard Ligatures, like all the other non-legacy ligatures.

Just automatically converting these two characters to an old legacy single-character should not happen. That is the point of this original post.

In jest... @Luc(as) is fairly knowledgeable about this stuff. The old joke applies here - he has probably forgotten more about fonts than I will ever know. They should listen to him.