Preview Options for mark positioning

I have just downloaded a trial version of Glyphs 2.5.1. I like many of its features, but I am very puzzled about how to preview the effects of open type positioning features.

The manual states (p. 47) that the preview option will work only for substitution features and not for positioning features. I assume this means that the effects of mark-to-base and mark-to-mark will not show up in preview?

The suggested solution, as I understand it, is to continually export the font to your Adobe fonts folder and to test the outcome using “any” Adobe application. But which Adobe application are we talking about here? (The manual doesn’t say … I suppose I should already know, but I don’t.)

But I don’t really feel like buying InDesign, for example. It’s not really in my current budget. I am not a professional font desginer or graphic artist, but an academic who makes fonts for extremely specialized uses and which have no real market value.

Is it really the case that without InDesign, you can’t really do what you need to do with Glyphs? (I consider mark-to-base and mark-to-mark to be essential open type features, not fancy add-ons.)

Does anyone have a suggestion for getting around this problem that does not involve shelling out a load of money to Adobe?

Thanks — I really would like to use Glyphs if I can.

There are some options that are if you select an anchor, it shows a “cloud” of all accents that can attach on this letter and all letters in the edit view. And if you type some letters and select an anchor in a mark glyph, then you see that mark in all the other glyphs.

Just to be clear, I did type ACGJ, not their accents variants.

Another thing you can do, since the major browsers have excellent OpenType support, is use a font testing page. This one is a classic:

Just drag your font in, and it will be displayed with a generous selection of OpenType features. Mark positioning is enabled by default. Or for a variable font

which annoys somewhat with its busyness, but works well for testing all of a font’s features.

LibreOffice also has excellent OpenType support (though no API for it: you have to suffix feature tags to the font name), including mark positioning, which is on by default. (But unfortunately you have to install the font to test in LibreOffice.)

If you want to do more specific or advanced previews, you can try the Show Mark Preview plug-in from Window > Plugin Manager. It just stacks all combining marks you insert into Edit view onto all letters you insert in it.

You can also use the free TextPreview. But you cannot preview PS hinting with it. I assume you know how to insert combining marks?

Thanks to all of you for your very helpful replies.

I will try these options and see what I can do with them.

I do use LibreOffice and OpenOffice to test open type features as well as Mellel, which does a good job with some (but not all, depending on the script in question.)

I really appreciate that people responded to my question so quickly.

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Is it still possible to show the accents by clicking an anchor? Since the Glyphs 3 Update i cannot see the “ghost accents” any more. Is there a way to switch this option on and off? :slight_smile:

There is a “Display Mark Cloud” option in Preferences > Appearence.

I’m using an M1 Max with Monterey 12.5.1, Glyphs 3.1
I’m rebuilding older fonts, that used ccmp, to use mark to mark positioning. I exported to both .ttf and .otf.
What I think I’m seeing:

  1. Font Goggles and axis-praxis appear to properly use the m2m positioning that I set
  2. I couldn’t get Text Preview to work
  3. The mark clouds seem to be okay
  4. I loaded the Show Mark Preview plugin, but it doesn’t appear to be understanding my m2m. Maybe I’m not using it properly.
  5. I checked with Word, Pages and Mellel and they do not appear to be using the m2m positioning. The marks are somewhat mashed together in their own fashion.
  6. doesn’t seem to exist any more.

What am I doing wrong?


How are you testing? This is probably a font cache problem. Read this please: Eliminating font cache problems | Glyphs

Thanks for the feedback. This is a brand spanking new clean install (M1 Max) with no 3rd party fonts. All apps were clean installs with no migration or restores. I’ll try the safe mode and AppleScript route and report back.

If the works in a browser and FontGoggles, the font seems to be fine. Can you send me the .glyphs file?

Safe mode didn’t seem to help. The AppleScript clean cache seemed to work, but I don’t know why. I restarted after install. Odd because this font was never installed on this system, so I didn’t think that caching was a problem…but I’m wrong. However, mixed results now:

  1. Font Goggles does the best job of rendering
  2. Apple Pages is okay, but less readable
  3. Mellel is slightly better
  4. Word is doing something weird. Almost looks like font substitution. No m2m positioning (commaabovecomb overshoots the headspace) and the corners of the commaabovecomb are rounded. With word I looked at Advanced/Styles, but that didn’t change anything.
  5. I exported the word doc to PDF and opened in Acrobat. It shows the oddities even more
  6. I don’t have InDesign, so will need to punt it to the user for eval.
  7. I do have Photoshop, and rendering looks as good as font goggles

Do I need to look at both m2m and ccmp for ‘belt and suspenders’, or is there something I’m missing or doing wrong with Word?


Again, how are you (re)installing your fonts for testing in all those apps? New Macs also have a font cache.

The Word screenshots clearly show a different font. Word uses fallbacks if a character is not covered by a font.

In the past I have used Font Book to delete the family, restart the computer, re-install the font, restart the computer. This has generally worked okay in the past. I just read the articles on clearing the font cache. I installed the “export and install” plug-in and will begin using this on my workstation for future testing. I noticed that FontExplorer X has a clean cache function, but I also read that they seem to be discontinuing Mac support. I’ll need to find an end-user solution (app) where users may not have admin access to run cache scripts.

I did my standard delete/restart/install/restart process and now the font and combining glyphs are displaying better in Word. But not as good as with other apps. I’ll need to tweak the mark positioning and maybe reduce the height of the combining glyphs.

Any hints on how to configure/use the “Show mark preview” plug-in? I must not be implementing it correctly in text mode. The combining glyphs just appear to the right of the main character.

Thanks very much for the hints and advice on cache cleaning issues.


I read additional articles on cleaning the font cache. A number of them also suggested running a permissions fix after the cache clean. Is this also a good idea?

The edit view does not do mark positioning. That would be a bit confusing and difficult to work with. Try the Text Preview window of full OpenType (GPOS and GSUB) preview.

Thanks for the advice.

For our work we have options where there is a C + caroncomb + commaabovecomb.

When I have C open I properly see the caroncomb, commaabovecomb, acutecomb (but not gravecomb) mark shadows above the C. However, when I open the caroncomb, I only see acutecomb and gravecomb mark shadow above the caroncomb (not commaabovecomb). I have top and _top anchors set for the commaabovecomb. Is there something I need to enable/configure to see the commaabovecomb mark shadow or am I not understanding this process?
Also, is the Text Preview window dynamic (auto updates glyph display while anchors are changed) or do I need to open/close the window to see changes?

Interestingly, with the “Show Mark Preview” plugin enabled, the caroncomb and commaabovecomb display properly if I type them to the left of the C (instead of the right side as I would normally type). However, I’m probably not understanding how the plugin works.

The built-in mark cloud is a reference for positioning your anchors. It has a predefined set of typical marks per letter.

The Mark Preview plug-in gives you a preview of mark-to-base and mark-to-mark. It takes all the marks you have in a line, and puts them on all the letters you have on the same line. See the description of the plug-in for more details.