Bitcoin Glyph in Unicode Private Use Area

[AliceWonder]

I posted this in development but I think this might be better suited since it is not code related. So I locked that one. Discuss here.

Hello,

I'm designing a few fonts and I would like to add currency glyphs for bitcoin and namecoin.

Until there is an official currency symbol with an official unicode assignment, any bitcoin symbol in a font (that is not an existing glyph anyway) will need to be assigned to the private area.

I would suggest that we pick a number in the private area that font creators can use for bitcoin until such time that an official unicode assignment is made.

More on private use areas: http://en.wikipedia.org/wiki/Private_Use_Areas

I would suggest that we attempt to pick a number that is not already in public use. For example, Apple Computer uses U+F8FF and http://www.evertype.com/standards/csur/ has un-official assignment for many scripts not in unicode, such as Science/Fantasy fiction languages.

Having an agreed upon Private Use number for the Bitcoin currency symbol would allow us have consistency when changing fonts, the character could easily be used in PDF and ePub documents by embedding the font, and could probably even be used on web pages by specifying webfont that use that number for bitcoin.

My suggestion is that we only agree upon a number, allow the font authors to decide which proposal they want to draw in their font. I like the one by Pander and that is what I will add to my fonts, but by using a consistent number in the unicode private range, until there is an official symbol agreed upon, let the font typographers pick what they like.

When we do pick a number, https://en.bitcoin.it/wiki/Bitcoin_symbol should be updated to reflect it, so that font creators who don't come by the forum but google the currency symbol can find it.

Thoughts?

[AliceWonder]

Well I guess I'll just have to pick something myself, does anyone know of any fonts that already using something in the private use area for a bitcoin glyph?

[Kazimir]

Font Awesome uses U+F15A: http://fortawesome.github.io/Font-Awesome/icon/btc/

[AliceWonder]

Thank you.

Another option is to use the generic currency spot (U+00a4) but as a special feature alternative to the standard generic currency glyph.

I'm not sure if special features work with WOFF which is what would be best for a web font, but if it is done as a font feature glyph,

Code:

.btc { font-feature-settings: "btc" on; }

Fonts that have the btc feature, in browsers that support font features, would use the btc glyph. Other fonts and browsers that don't support font features via CSS would display the generic currency symbol, which most fonts have because it is part of ISO-8859-1 (generic currency symbol is ¤)

[Kazimir]

Not familiar with these font features, but I doubt if many fonts will support them. I guess by using U+00A4 (and btc feature glyph), in most cases it will result people seeing the generic ¤ symbol.

[AliceWonder]

Not familiar with these font features, but I doubt if many fonts will support them. I guess by using U+00A4 (and btc feature glyph), in most cases it will result people seeing the generic ¤ symbol.

Font Features are part of the OpenType font specification.

The most common use of them that I personally have seen is with small-caps, the font can have smaller versions of upper-case letters as alternatives to the lower-case letters without needing to have a completely separate font.
Another common use is dotted zero vs regular zero.

Most software has a way to access the alternate glyphs.

Since WOFF is basically compressed OpenType it should work with web fonts too via CSS, but I haven't tested, it may be browser-dependent.

It certainly won't work with old browsers, but that's the beauty of it - it uses the same unicode value but is just an alternate glyph, so someone using an old browser (or a text console browser where no fonts are supported) will at least get the generic currency symbol from ISO 8859-1 rather than missing glyph indication.

[buzybit]

really nice idea - well done
it should be used in the unicode assignment, but we have to wait for around 2 years to watch that happen