How to match font metrics between PC and Mac

Dan_Kreider · April 6, 2024, 2:15am

After using PC my whole life, I’ve started using a Mac laptop as a second device.

I’m finding the software I use causes differences in the renderings of fonts between PC and Mac, which you can see demonstrated here: Inconsistent export between Mac and PC - #11 by dan_kreider - Dorico - Steinberg Forums

This is a big problem for me. I want to be able to render files on both PC and Mac with no differences.

What font metrics should I be matching? Somehow I can’t get it to match correctly, no matter what I try.

Thanks in advance!

ErwinDenissen · April 6, 2024, 6:29am

This is a tutorial about metrics:

Let us know if this works for you.

Dan_Kreider · April 6, 2024, 11:15am

Thank you Erwin, I read through it and it’s very helpful. What I’m still not totally clear on is how to fix it.

To explain: I have thousands of files that have been rendered on PC. Now that I’m using a Mac as a second device, I want my Mac renderings to match the PC renderings.

Although I haven’t tested it, I am told the program I’m using (Dorico) renders Academico font the same on Windows and Mac:

Here are the metrics for the font I am using:

I assume I should change the values for Ascender/Descender/Line Gap? Should they be 700/-300/140? I hope to understand the correct solution before trying it, and causing a mess across multiple machines and files… Thank you!

Dan_Kreider · April 11, 2024, 10:57pm

Sorry for bumping this thread, but I’m really desperate for a solution. Could anyone give advice about how to modify the font metrics so that the Mac installation will match existing Windows files?

Thank you!

ErwinDenissen · April 12, 2024, 7:04am

FontCreator 15 has a button that calculates the values. It is mostly based on the suggestions from the tutorial.

Do give it a try and let me know if that works.

Dan_Kreider · April 12, 2024, 11:40am

Thanks, I upgraded to 15, but I’m still not sure what to do.

I need to keep the Windows values unchanged, but only change the Mac values so they match.

I have read through the tutorial, but I don’t know what to do with the “Calculate” button.

I’m really quite desperate. Thank you!

ErwinDenissen · April 12, 2024, 12:16pm

I am afraid it will only work if you use the calculate button, but then most likely all values are updated.

There are numerous other attempts to streamline metrics; for example:

github.com/googlefonts/gf-docs

VerticalMetrics/README.md

main

# Vertical Metrics:

Throughout countless threads and discussions, the following rules have been established.

### 1. Vertical metrics must not be calculated by the font editor automatically
We don't want this because they all do it differently. 

### 2. Vertical metrics must be consistent across a family
Every font in a family must share the same vertical metric values.

This rule can be voided if a font is being upgraded and previously had inconsistent family metrics. If this is the case, the aim should be to visually match the linespacing of each font, but fix any clipping issues caused by incorrect WinAscent, WinDescent values.

### 3. The following vertical metric parameters must be set for each font in a family

| Ms Spec ttf spec      | Glyphsapp Master customParameter | FontLab              | ufo3 fontinfo.plist      |
| --------------------- | -------------------------------- | -------------------- | ------------------------ |
| [OS/2] sTypoAscender  | typoAscender                     | [OS/2] TypoAscender  | openTypeOS2TypoAscender  |
| [OS/2] sTypoDescender | typoDescender                    | [OS/2] TypoDescender | openTypeOS2TypoDescender |
| [OS/2] sTypoLineGap   | typoLineGap                      | [OS/2] TypoLineGap   | openTypeOS2TypoLineGap   |
|                       |                                  |                      |                          |

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Dan_Kreider · April 12, 2024, 12:42pm

Ok, I found a solution. It didn’t use the calculate button, and I didn’t need to upgrade to 15, although I was happy to support the development of this wonderful program.

I simply set the values of Ascender and Descender to match Win Ascent and Win Descent, and set the Line Gap to 0. It causes the font to render exactly the same on Mac as it does on Windows:

Dan_Kreider · April 12, 2024, 12:54pm

Do you foresee any potential complications from the way I did this?

ErwinDenissen · April 12, 2024, 1:00pm

I am glad you continue to support our software and I am pleased you seem to have found a solution!

Not really, but I am sure there are situations where it no longer matches. Probably when used in Adobe software…

Dan_Kreider · April 12, 2024, 1:04pm

Thanks. But doesn’t Adobe use Typo values? So it wouldn’t be looking at Win Ascent/Descent and Ascender/Descender then?

I didn’t change the Typo values.

ErwinDenissen · April 12, 2024, 7:33pm

I think there are 3 shaping engines that are used in the last years, a default one, a composer, and Harfbuzz. Not sure if all use the same metrics.