Don't font vertical metrics ever affect leading in InDesign?

Ori Ben-Dor

I'm doing a small revival project, and I'm trying to match the original source as best as I can, including the leading.
But it seems that, when it comes to leading, InDesign doesn't care about any vertical metrics parameters (ascender, descender, line gap, etc.); all it cares about is its own leading measure.
Is that so? Don't font vertical metrics ever affect leading in InDesign?
And if that's indeed case, does it make any sense to you that the leading publishing application just ignores the font's wishes in this department?

Rafael Saraiva

every app / platform has its own way of handling it Android for instance uses the bounding box which is weird. so you won't get exactly the same results for default leading across different platforms. 

what you can do about InDesign (if you want to stick to it) is creating rectangles mimicking your vertical measurements as in OS/2 and hhea to try to figure out how Indesign handles it. another solution which is more universal is proofing your fonts on the web.

Ori Ben-Dor

Thank you for your comment, Rafael.
But I'm not looking for an alternative to InDesign for proofing purposes.
I'm just trying to figure out if my impression that InDesign completely ignores vertical metrics (when it comes to leading) is correct, and if there's some way around this (in InDesign, that it).

Rosalie Wagner

You can read this tuto for vertical metrics, it triggers a little bit why Indesign is reacting this way. From experience, it definitely reacts to vertical metrics but the default linespacing (baseline to base line) is something like 120% of Ascender+Descender distance (but from which table I don't know). So no, I would say it doesn't take linegap values into account. 
https://glyphsapp.com/tutorials/vertical-metrics

Ori Ben-Dor

I'm using InDesign 2020 for Mac.

Here the baseline-to-besaline distance always equals InDesign's own leading parameter, regardless of the font or its vertical metrics properties.

For example, if I have the leading parameter set to 72 pt, then the baseline-to-besaline distance equals precisely 72 pt. This can be easily demonstrated by placing a rectangle on top of the text box and setting its height to 72 pt.



Ascender+descender distance doesn't affect the baseline-to-baseline distance at all. This can be easily demonstrated by changing fonts and observing that while the baseline moves up and down, the baseline-to-baseline distance remains the same (i.e., every line moves up or down by the same measure, maintaining their distance from each other).

It's probably worth mentioning that while it's possible to set leading to auto, auto leading simply means font size multiplied by some factor (the default being 1.2, or 120%). So that doesn't help. Once again font vertical metrics are being ignored and baseline-to-baseline distance is decided solely based on an InDesign font-independent parameter, only this time it's the font size instead of the leading.

Does InDesign behave differently for you? Is this behavior configurable? That is, is there anything I, as a user, can do to stop InDesign from overwriting vertical metrics with its own parameters for deciding the baseline-to-baseline distance? 

Rosalie Wagner

Indesign uses the UPM value to calculate how the glyphs are going be rendered at a certain font-size. If you change it, the font will appear bigger or smaller for the same font-size. The baseline-to-baseline distance will always be the same, but there will be more or less white space between the bottom and the top of your x.

I don't think you can configure the default one ("auto"). But if you manage to do so, please share.

Thomas Phinney

Funny, I never ever thought of this as a problem. Instead, I always found having font linespacing varying wildly at the same point size, a problem. So, InDesign’s default behavior is exactly what I want it to be.

Of course, the other behavior might have seemed problematic because my main experience of it is from Microsoft Word using WinAscent/WinDescent, which basically means the font BBOX. And that is usually unappealing.

So, sure, it would be nice to have an option to use the Typo metrics from the font, to determine linespacing. Even if I prefer to set it myself.

Theunis de Jong

@Rosalie: of course you can change the "Automatic Leading" percentage! Its value is set in a Paragraph's Justification dialog. There you will see that default "120%", and you can change it to your heart's content. (With some reasonable upper and lower limits.) I even prefer changing it there, rather than setting it at a fixed value, because that means I can place inline images using that same style, which makes their total size automatic. (The image height, plus – weirdly enough – something like "+x% of the original font size when above 100%". If those few points extra at the top bother me, I set the Auto Leading to exactly "100%" and they disappear. It still beats manually scaling every figure box.)

See InDesign's Online Help for the official instructions:
https://helpx.adobe.com/indesign/using/leading.html#change_leading

The only place I know a font's internal measurements are taken into account is in the settings for "Top line at x" in a frame's general settings. There you can use one of "Capitals", "lowercase", and "ascender" (plus "Leading" and a manually entered fixed value, independent of the actual font's size & leading). I don't know if these values are read from the font's file or just measured on the fly; as it also works with Type 1 font files, I suspect the latter.

Other settings that get used are underline and strikethrough thicknesses and offsets – when left unchanged, there may be a difference between two styles of the same font. A big minus point for me is that while you can manually set them to some hard value, then they become independent of the font size, so other sizes need other values ...

It's worse for super-/subscript sizes and offsets. You can set their relative values in %, but only in a single global dialog (under Document Preferences) for an entire document, and you cannot set it to "use the designer's values". I've been lobbying for that addition but it never got any traction, so I had to write a script to read their values straight out of a (single) font's file.

Ori Ben-Dor

I have no objection to InDesign's behavior being the default one. But not having even the option to use the font metrics? That's not very nice. And weird.

John Hudson

It's not weird if you remember that InDesign is primarily a page layout program, so deals with typography in terms of type size and type leading (linespace height). Font metrics provide fallback linespacing in environments where the leading is not explicitly controlled by the user.

That said, the default used by InDesign (leading = 120% of type size), is very Latin-centric, and isn't appropriate for a huge number of other writing systems. This means that users of those writing systems either need to set their own default (which one can do in ID preferences), or always manually set the leading. In this situation, I think it would be helpful if InDesign were to at least offer users feedback from the font metrics as to what appropriate leading values might be for a specific font.