thanks for opening the discussion - there have been concerns about the term leading since 2018 😆

+1 for renaming the leading value to normal

that way it would be easier to memorise the value of the normal css behaviour.
it would also match with the initial value of text-edges and similar font properties:

leading-trim: normal;
text-edge: normal;
line-height: normal;
...

+1 for the value normal

totally agree with @jantimon it fits in much better with the existing values.

A suggestion for an alternative to text-edge could be text-box-sizing. This would align it with existing terminology used by other properties, e.g. box-sizing.

Example in context:

.paragraph {
  font-size: 1em;
  text-box-sizing: cap;
}

+1 for the text-box suggestion by @michaeltaranto.
Imho the consistency in terminology brings clarity and simplifies comprehension.

Here are some more examples:

default:

.paragraph {
  text-box-sizing: normal;
  text-box-trim: normal;
}

cap ✂️:

.paragraph {
  text-box-sizing: cap;
  text-box-trim: both;
}

cap alphabetic ✂️:

.paragraph {
  text-box-sizing: cap alphabetic;
  text-box-trim: both;
}

👍 renaming leading-trim and 👍 @jantimon’s text-box proposal above. This solves much of the confusion with the term leading.

I have been confused with the term leading here as this trims into the em box, not just the leading. Additionally design software and historical letterpress typesetting often use the term leading in conflicting ways. In my opinion, the term leading is best to avoid where possible.

+1 I think text-box (including text-box-trim) works here and aligns with some naming conventions of other CSS properties like text-transform, text-decoration, ++ and now text-wrap. Also reminds me of border-box/content-box, but for the text box, which seems like a good analogy here.

👍 for text-box-sizing and text-box-trim suggested by @michaeltaranto. As @una said, it works well with other naming conventions.

I would suggest shortening the property name. For example, having text-trim and text-sizing is easier to type and memorize.

Ben Holmes proposed to use none as default value for text-box-trim.
So the default behaviour values might be even easier to understand:

text-box-trim: none;
text-box-sizing: normal;

👋 Hi. I want this feature. I was asked to comment. I would probably yield to whatever @scottkellum thinks, he's the real expert.

I support the text-box-* naming system. I personally think of "leading" as the space between lines of text, and not so much the space added to the glyphs themselves which is what we're manipulating here.

I'd probably down vote text-edge. Makes me think of the text "river" at the inline-end edge of text reflow.

Appreciate all the work y'all are doing on this. Thanks!

Thank you for the kind words @davatron5000, lots of experts here but I’m glad my feedback is valuable. Tagging @nicksherman as I know he has thoughts on this that would be valuable to have documented in the thread.

I just want to emphasize that giving them the same prefix makes it easier to introduce a shorthand for them. And those properties are presumably often used together.
Therefore, I am all for a shared prefix.

Sebastian

I strongly support using almost anything other than leading. As @scottkellum already mentioned, it's a confusing and inconsistently used term which doesn't even fully make sense in this situation. I would even go as far as to say leading should be avoided for any typographic CSS terminology. (I'm very happy they named it line-height and not leading.)

The text-box naming seems like a good alternative to me, not only because it removes any of the confusion built in to leading and is more applicable, but also because it's just naturally more intuitive and accessible. Eliminating the need for a history lesson about thin strips of physical metal used in traditional typesetting (never mind how to pronounce it), means one less hurdle to learn these new properties.

Hi everybody. I’m really looking forward to this feature.
May I bring in some toughts too? Because this is more then 500 years old craft, I recommend using "real" typografic terms as much as possible. I just stumbled over "alphabetic". If I understand everything the right way. This should be named "baseline". And "cap" should be named "cap-height" because a cap is filling the room between the baseline and the cap height. And yes, if you trim the leading of a text, every line would be piled up. And a single line has no leading.

Should I dive deeper and make some proposals? I don’t want to bother you.

@jwssnr There are multiple baselines, not just the one you're used to calling "the baseline". I suggest reading through the css-inline spec starting from the top. https://www.w3.org/TR/css-inline-3/#intro

@fantasai Sorry. First let me say this ist my first contribution to such a thing. So maye I do it It the wrong way. Second I have difficulties reading English. So I’m not able to read AND fully understand the specs.
But as a typographer and even a little familiar with type-designing techniques, I know one font has a lot of horizontal rules but only one baseline — at least in it’s origin context and in stable webfonts. Are you sure there are multiple baselines written in the specs? If so this would be quiet confusing.

@jwssnr I appreciate that this is your first time contributing. Might I make a suggestion that you take the spec author at their word, or at least dig into the context they provided. @fantasai has been deeply immersed in this for years and has done outstanding research on this subject.

I also understand that English is the language specs are both written and discussed in and that is a barrier to entry that does not provide equitable access to participation. To help visually describe things, there are diagrams that highlight the different baselines needed for different writing systems in the spec: https://www.w3.org/TR/css-inline-3/#css-metrics

In your Devangari example, the Headline Top, Devangari metric is the hanging baseline in the spec. The baseline is used for alignment in CSS. Having specific baselines for different writing systems helps provide more consistency. Imagine you have two Devangari fonts with different metrics, you would want them to align at Headline Top, Devangari, not the alphabetic baseline, correct? That is my understanding of why the spec is written the way it is.

Hi. I think I have understood the spec so far on this point. One is the question where the CSS user wants the alignment. I think that's great so far. And I think your work is extremely important and I'm very excited to be able to apply that soon. It's just a matter of the specific names of those lines where the glyphs are aligned.

I know, different writing systems use different lines to align the glyphs - hanging, standing, centered ... Literally translated from German to English, we call this writing line.

But baseline is a fixed term in type design. No matter what type system, there is always only 1 baseline in the metrics. Even hanging typefaces are designed to work with a baseline, even if it is not visually recognizable. This is also important so to combine different font systems in one text.

I would like it if you could access the established terms in the font metrics via CSS. So I would just call what you guys call alphabetic, baseline.

There is a second point to add. If I want to trim the space around the text from the top down to baseline in the metric, as I've outlined here, alphabetic might be misleading.

It could well be that I really don't see through it all. If so, I'll shut up from now on and look forward to the result of your work. Thank you so much. 💐

@jwssnr

I would like it if you could access the established terms in the font metrics via CSS. So I would just call what you guys call alphabetic, baseline.

I have a very basic understanding of the terms used in typography. Though the specification defines different types of "baselines" for different writing systems. And it defines the word "baseline" as the line along which individual glyphs of text are aligned. According to the spec., the "alphabetic baseline" is used in Latin, Cyrillic, Greek and other scripts, while the "hanging baseline" is used in Tibetan. There is also an "ideographic central baseline" which is halfway between the "ideographic-under baseline" and "ideographic-over baseline".

As I understand you, your claim is that the specification misuses term "baseline" as the line used for alignment and "baseline" only refers to the a specific line somewhere at the bottom of the characters. And there is no such thing as an "alphabetic baseline", "hanging baseline" or a "central baseline" in the terminology of typography. Writing systems that use the hanging line to align their characters still have a baseline somewhere at the bottom of the characters. Though that baseline is unrelated to character alignment.
Does that summarize your concerns correctly?

Sebastian

Many of these terms are used in the OpenType spec at https://learn.microsoft.com/en-us/typography/opentype/spec/baselinetags. CSS text layout works with OpenType fonts, so the language should reflect that.

@SebastianZ Yes, that’s almost what I wanted to say. I’m not talking about typographic terms in the sense of their origin, but about the actual terms for in type metrics. These lines are called:

• Ascender
• Body Height
• cap height
• x-Height
• Baseline
• Descender

The pink line in the figure above shows the baseline. Font designers design their fonts to align well with other type systems. Of course, it's great if you can also set the alignment to the x-height or cap height. https://www.w3.org/TR/css-inline-3/#baseline-tables

The baseline in the digital fonts has its origin in the Latin script — typical for software development. But it is not bound to the Latin script or to "alphabetic".

@faceless2 In Glyphs, for example, there is actually the possibility to set the baseline tags, but this is rarely used. So this info is very rarely available in fonts. Maybe that will change.

The CSS Working Group just discussed [css-inline-3] Naming Stuff, and agreed to the following:

• RESOLVED: leading-trim: normal; >> text-box-trim: none; AND text-edge >> text-box-edge

I updated my examples on https://github.com/jantimon/text-box-trim-examples

text-box-trim: both

text-box-edge: normal

text-box-edge: text

text-box-edge: ex

text-box-edge: ex alphabetic

text-box-edge: cap

text-box-edge: cap alphabetic

text-box-edge: ideographic

text-box-edge: ideographic ideographic-ink

text-box-edge: ideographic-ink

text-box-edge: ideographic-ink ideographic

Edits for renaming leading-trim to text-box-trim (and its normal value to none) and renaming text-edge to text-box-edge are in 67822bd. Leaving this issue open for further bikeshedding. :)

Here's one idea: should we rename text-box-edge: text to text-box-edge: from-font? Since this is the ascent/descent requested by the font. (Matches the from-font keyword we have in a few other places.)

Just landed the edits for #8829 (comment) in 7869dc6 and posted a new naming issue to solidify those edits. The proposed syntax is:

<text-edges> = [ text | cap | ex | ideographic | ideographic-ink ]
               [ text | alphabetic | ideographic | ideographic-ink ]?
<text-trim> = start | end | both

/* line box sizing property (inherited) */
line-fit-edge: leading | <text-edges>

/* leading-trim properties (non-inherited) */
text-box: normal | <text-trim> || <text-edges>
text-box-trim: none | <text-trim>
text-box-edge: auto | <text-edges>

Have a look at the details in the issue and let us know what you think!

Spec is at https://drafts.csswg.org/css-inline-3/#leading-trim FWIW.