Re: U+25CA LOZENGE - why is it in the "Mac OS Roman" character set (and therefore widespread in current fonts)?

From: Mark Davis ☕ <>
Date: Mon, 13 Aug 2012 13:18:54 -0700

I joined the Lisa group in late '83, and that was soon absorbed into the
Mac group.

As I recall, the MacRoman character set was already done, based on the
Lisa. This predated the laserwriter, so that wasn't the origin. The long
'f' was for use as a currency symbol (particularly for Gulden). I don't
know where the lozenge came from, but the purpose was not for mathematical,
logical, or accounting purpose (as Peter said). I believe the main purpose
was as an alternate bullet shape.

Mark <>
*— Il meglio è l’inimico del bene —*

On Mon, Aug 13, 2012 at 12:25 PM, Ken Whistler <> wrote:

> On 8/13/2012 10:11 AM, Peter Edberg wrote:
>> I do not believe it was for accounting, logic, or mathematical use. It
>> was included in the original "Macintosh" character set as shown in Figure 2
>> of the Font Manager chapter of Inside Macintosh, volume I (1985), but was
>> not included in the shaded "mathematical" set in that figure. At that time
>> it was shown with a shape more akin to that of U+25C7 WHITE DIAMOND. I
>> think it may have been intended as an unfilled complement to the BLACK
>> DIAMOND used as one of the Menu Manager user-interface elements at
>> 0x11-0x14 in that figure. However, by the time of Inside Macintosh: Text in
>> 1993, the character was shown with a shape more akin to that of U+25CA
>> LOZENGE (see Figure 1-36, "The Standard Roman character set").
>> I do not have any definitive word on this since I was not involved in the
>> creation of the original Macintosh character set.
> Adding on to Peter's information, in an attempt to be slightly more
> definitive...
> People are missing the fact that the lozenge as encoded at D7 in MacRoman,
> but *also* was E0 in the Symbol set for the Mac. And E0 in the Symbol set
> was mapped to "lozenge" in PostScript. So the proximate reason why U+25CA
> appeared in the Macintosh character sets can be laid at the feet of
> LaserWriter
> PostScript support, I suspect.
> We did consider, back in 1990, whether the MacRoman D7 should be mapped
> to U+25C7 WHITE DIAMOND, instead, but the decision, for whatever reason,
> it was decided that MacRoman D7 and MacSymbol E0 were both lozenge. That
> may account
> for the shape change that Peter mentions in documentation from 1993.
> There is some early font information which suggests that the original
> intent,
> however, may have been to have an open diamond. If you look at high quality
> font documentation, e.g., the HP Book of Characters from 1992, the "MC Text
> Symbol Set (12J)" shows an open diamond shape at D7, instead of the
> lozenge.
> But the confusion regarding the identity of this character can be
> illustrated by
> comparing the "MS: PS Math Symbol Set (15M)", which shows an open diamond
> at E0, versus the "AS: 'Symbol" Symbol Set (19M)", which shows a lozenge
> shape
> at the same position. Both of those fonts are clearly intended to cover the
> same set, although the glyphs are all separately designed. Settling on the
> lozenge
> may have had more to do with Adobe designs winning out, rather than
> anything
> else.
> An open diamond is also rather common in various mathematical pi fonts from
> the era, including Ventura Math, which was also closely related to the
> Adobe
> symbol encoding.
> Of course, it is a separate question as to why lozenge (or open diamond)
> was added
> to the MacRoman set in the first place, as well as the Symbol set -- that
> may
> have something to do with early notions
> about user-interface elements, as Peter surmises, but the fact that it
> wasn't carried
> over into most of the early non-Roman character sets for the Mac would
> indicate that
> even if it had been intended as a user-interface character of some sort,
> that was
> dropped in international usage.
> I agree with Peter that the choice probably had nothing much to do with
> accounting, logic,
> or math per se, except insofar as one of those usages may have figured
> into the choice
> of elements for the original PostScript symbol set.
> I can trace it back to a 1985 edition of the PostScript Language Reference
> Manual.
> If people *really* want to know what it was "for", I would suggest
> starting there and
> digging back further into the documentation trail at Adobe Systems prior
> to 1985.
> John Warnock is still around -- somebody who knows him could presumably
> just
> ask him. ;-)
> Regarding another stray comment in this thread, Michael Everson said:
> "The LOZENGE is also found in DOS code page 437."
> That is definitely not true. Michael may be misremembering the diamond
> from the
> set of 4 card suit symbols, which definitely are in DOS CP437.
> --Ken
Received on Mon Aug 13 2012 - 15:20:46 CDT

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