Okay, so like, I'm aware the Character Viewer (⌘ + ⌃ + space) is displaying a system index of the full supported Unicode set of chars. Z My question is, is there a way I can take a glyph I've created in, say, photoshop or illustrator and either supplant/replace one of the system glyphs, or somehow bootstrap it into one of the Private Use Area (E000) blocks inside the unicode table? I totally understand this would be a local only modification and that nobody else would see it, as they would lack the custom glyph. That's fine. I'm even fine if the value of the glyph doesn't align with the visual output (so if I were to overwrite the letter "e" with billiard ball - this is a "'as a for instance," NOT my plan, lol - it would still sort between "d" and "f" still - this is not a requirement, just saying I wouldn't care).

This is for personal use on my own system.

Presuppose I have the relevant software to create and save the glyph in any format required, raster or vector, including the ability to make it into any flavor of font or graphic file. The objective here is to be able to add custom glyphs as labels to icons, or the system-ui for my own use. Nobody else who's not on my MBP need ever see it; I just wanna know if I can override or modify that table.

...I mean, it's gotta be stored SOMEWHERE on the drive, right?

Edit: Okay, so, to further clarify: MacOS has a set of glyphs available to it by default, all built-in like, that it applies when rendering text. I favor using these when screen real estate is at a premium Example: enter image description here

(above: Important, Work-Related, Shopping, Movies, Music). The full set of supported chars is viewable in the Character Viewer...

But there are still hundreds of open "slots" that have either never been filled, or are foreign language characters Apple didn't see fit to bother with.. When you see a blank white rectangle ('▯') this is an unsupported glyph*.

So what I'm HOPING is someone knows how to actually not only make use of some of the open regions therein, but that also might know how to make the OS acknowledge their addition.

Private Use

*Apple calls them "tofu" and has gone pretty far outta the way to preclude their ever showing on screen. Fun fact: the OS-Shipped Noto Sans ("Noto" == "NoTo" == "No Tofu") font contains the MAJORITY of available glyphs

  • You can display your custom glyph anyplace where you are able to choose a custom font, but as far as I know these days there is no way to override the default font used by MacOS for things like labels or filenames or menus or dialogues in the user interface. Dec 17, 2021 at 12:39
  • @TomGewecke - you can persuade some unicode glyphs to automatically substitute in such as file names. I don't know the rules by which this functions. I added an example to my answer below.
    – Tetsujin
    Dec 17, 2021 at 13:31
  • @Tetsujin Interesting! But I don't think you could customize any of those, could you? They still come from a default font that you can't replace. Dec 17, 2021 at 14:50
  • @TomGewecke - they're already subs. If I copy/paste to TextEdit & step through, the ones I used below show as Helvetica Neue, Lucida Grande, Hiragano Sans & Apple Color Emoji
    – Tetsujin
    Dec 17, 2021 at 15:51
  • 1
    @Tetsujin You are right, I tried a bunch of different ones, and there's no particular pattern of the font used for each. Dec 17, 2021 at 18:37

2 Answers 2


Too long for a comment but not yet sufficient for an answer

I'm not sure why out of the thousands of existing unicode glyphs you can't find one that will suffice.

A glyph is called from a font. If the current font does not have the glyph, the OS provides a substitute from another font that does. [I don't know how that mechanism works, but I used to work support on a cross-platform game where subs would work in Windows but not in Mac, even though the Mac could use the glyphs in any other app.]

So, you need to make a font, even if it contains only one glyph, in an address space not currently in use[1], then register it to the OS…. then provide some mechanism to be able to type it, eg from Keyboard prefs > Text.

[1] you can't replace 'e', or any already-used character or you'll only persuade it to show if you manually change the font for that one character - which you cannot do for a file name.

You can use some existing glyphs in file names, which should show on any Mac [Windows I couldn't say]
Where they file will be dependent perhaps on their Unicode numbering. I'm not sure how to test this thoroughly.
Enlarged example using a few fairly random glyps…

enter image description here

  • Where does that first glyph in your file name come from exactly? Dec 17, 2021 at 14:51
  • oh, the very first one is the icon, sorry, not a glyph
    – Tetsujin
    Dec 17, 2021 at 15:46
  • Because I have a desire to be able to do things like label certain elements with client logos, to reduce the amount of screen real estate they occupy. I can certainly produce the vector art and font file; I'll give this approach a go and report back.
    – NerdyDeeds
    Dec 25, 2021 at 15:22
  • (Also, no worries about windows support, or even "other computer" support. This is a customization for me, to streamline my own workflow; I don't expect it to propagate AT ALL outside of this specific box)
    – NerdyDeeds
    Dec 25, 2021 at 15:28

You mention "custom glyphs as labels to icons." Not sure I understand what you mean by that, but if you are trying to modify the icon of a file or directory in Finder, here's how:

  1. Create the image you want the item to have.
  2. Select and copy the entire image to clipboard
  3. Select the item to be changed.
  4. Get Info (Cmd-I)
  5. Click on the icon upper left of info window to select it.
  6. Paste to replace.
  • This centers more around attempting to alter the label TEXT. But shelving that, the question iteself is simply, Can I alter what MacOS believes to be the unicode character set, such that when character E000 (as a for instance) is inserted somewhere, MacOS thinks to itself, "well, there's a glyph there. Better render it!" in much the same way that if I insert one of the older unicode glyphs that has since been supplanted by an emoji, the OS performs the replacement (whether I want it to or not) whenever said char code is employed, by any application.
    – NerdyDeeds
    Dec 25, 2021 at 15:26
  • No, I was talking about the image that Finder displays as the icon for a file or directory. But if you want to change a font (or create a new one), that can be done. I haven't tried it, but I don't think it's easy.
    – WGroleau
    Dec 25, 2021 at 17:34
  • I know how and have the tools to make the glyphs and the font file. I'm just not crystal clear how to slip the characters in the produced font into the "default" slots of the unicode library referenced as part of OS-X's SystemUI font (or, indeed, if such a thing can even be done at all, though intuitively, it seems like it SHOULD be possible).
    – NerdyDeeds
    Dec 25, 2021 at 19:42
  • @NerdyDeeds Fonts actually contain the glyphs internally, attached to Unicode numbers, there's no referencing going on. So you could put your glyphs into a font at any code point which is empty in all installed fonts, and it should display by default. Except that the logical "empty" code points to do that would be the Unicode Private Use Area, and display of things in the PUA may not happen, even if the code point has a glyph, depending on the behavior or the OS and app. Dec 26, 2021 at 18:02
  • @TomGewecke - In fact, I stumbled into this fact by trial and error the same day I left my reply. It turns out, so long as SOME font file that's actively installed in the OS has a glyph present in a given Unicode address, the system will fall back to displaying it to avoid the dreaded tofu. Your answer IS the correct one; would you care to post it in an actual answer so I can give you the credit? Or shall I just summarize in the body of the question and close it out?
    – NerdyDeeds
    Dec 28, 2021 at 23:40

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