How do I use the xheight expression variable?

[GarryP]

In the Help (any application), in the “Expressions for field input” page, there is an xheight variable listed under the “Typographical variables” section which says: Use when setting the size of text.

And I was wondering how it can be used and where.

I’ve tried using it in various places and in various ways but nothing seems to ‘stick’; the original value in the field I try to use the variable in goes back to what it was.

I tried using (in Publisher 2.60 on Windows):

• xheight=15pt in font size fields;
• xheight+5 in font size fields;
• xheight/2 in font size fields;
• xheight/2 in the Paragraph Space After field;
• xheight in the Paragraph Leading field;
• xheight in the Decoration Top field;
• xheight in the Character Baseline field;
• xheight in the Character Leading Override field;

...and nothing seems to work.

Does anyone know anything about this and how to use it?

The same question also applies to the ascent and capheight variables?

I found these threads, but there seems to be some confusion as to what they are for, how they work, and even whether they work:

 

[thomaso]

I did not try your specific examples but it reminds me of a related issue with a not working variable, known / logged as AF-891:

[GarryP]

It seems as though the (possibly related) AF-891 bug has been flagged as fixed by the Serif Info Bot, but maybe it's not been fully fixed.

Either way, I’d still like to know how I’m supposed to use it, even if I can’t at the moment.

[carl123]

I can't get it to work either

and after getting ChatGPT to show me (where and how) all the places it could be used I finally got ChatGBT to admit to this...

 

"As of now, Affinity Publisher does not support the xHeight variable directly in text fields, expressions, or styles. While Affinity does allow expressions in some numerical fields (such as font size, leading, and spacing), xHeight is not a recognized variable within the software.

What Does This Mean?

• You cannot type xHeight * 2 in the font size or leading field and expect it to work.
• Affinity Publisher does not have a built-in dynamic x-height measurement system.

Possible Workarounds

If you want to maintain consistent x-height proportions across different fonts, consider these manual methods:

1. Measure the X-Height Manually

• Use the Text Ruler or Transform Panel to measure the lowercase "x" height in your chosen font.
• Then, manually apply values like x-height * 1.5 based on your measurements.

2. Use a Reference Font for Sizing

• Choose a base font with a well-defined x-height.
• Set a reference font size and adjust other fonts accordingly.

3. Create a Style Guide

• Define a set of styles based on x-height proportions.
• Manually adjust leading, paragraph spacing, and baseline shift to match.

Will Affinity Add xHeight Support?

There is no official confirmation, but you can request this feature from Serif’s Affinity Forums or their support channels."

 

Maybe Serif should comment on if this is currently a bug or not

[stokerg]

Hi @GarryP,

Great question! I've been looking into this today and also couldn't get them to work.  Quickly checked with QA to see if i was missing something obvious and they also can't get these to work.

I've logged it with the Developers and will update here with any information i get from them