From: Michel Suignard <[email protected]>
>To: philip chastney <[email protected]>
>Cc: unicode List <[email protected]>
>Sent: Monday, 17 December 2012, 23:37
>Subject: RE: wrongly identified geometric shape
>
I spent some times analyzing your documents and I can see you are trying to
harmonize the size of the diamond and the square shapes by applying the concept
that the length of a side should dictate the ‘size’, not the ink height. By
doing so you force the rule found on small sizes to the larger sizes which
makes you deviate from the current TR25 recommendation, basically you are
sizing down all the squares to match the diamonds.
Oh no, not at all -- quite the contrary, in fact.I started from the text of UTR
25 -- the shape tables available before version 8 weren't particularly useful
for my purposes. Back to basics is the best approach here.
If the intention is to conform with UTR 25's recommendations,
the two essential processes are :
(i) scaling for visual impact, so that all shapes of the same size
have equal “visual impact”, a process applied down each column of Table 2.5, and
(ii) scaling for graduated sizes, a process applied along the rows.
AFAIK, these requirements (suggestions) have always been a part
of UTR 25.
Any proposal for more sizes would need to explain whether, and how, the new
sizes are to be fitted into the existing graduation (smoothly, even steps, half
steps, whatever).
The graduation process had a deleterious effect on the function composition
symbol (as described in Shapes II, §7), which led to the Curious Incident of
the Howl of Rage from the mathematical community. Any proposal for more sizes
would need to identify any similar side effects.
Shapes II, §8, explores the problem of circled circles. Any proposal for more
sizes would need to produce a similar solution for the proposed new set of
sizes.
The “equal visual impact” process is illustrated in Shapes II, §2.
All objective measures of equality (equal height, equal width,
bounding box, circumscribed circle, areas of ink) look “wrong”
for certain shapes. A few years ago, Asmus Freytag suggested
using equal areas of ink, which could then be scaled to give
equal “visual impact”. This scaling would necessarily be
subjective, and could therefore be applied to any arbitrary
size. Starting from equal areas of ink minimizes the variance,
and this, IMHO, is the best approach.
One way of meeting UTR 25's requirements can be found on p18 of Shapes II.
UTR 25's Table 2.5, is not a good source for measurements. The
diamonds and lozenges, U+25c6, 25c7, 29eb and 25ca, are shown in
the “regular” column, but with “medium” sized glyphs. The
diamonds and lozenges, U+2b25~2b28, are shown in the “medium
small” column, even though TUS says they’re “medium” sized. It’s
been that way now, for over 5 years. To the best of my
knowledge, only 2 people have noticed this inconsistency, and
only one has publicly commented, which surely counts as another
Curious Incident.
Curious Incidents were first introduced to the public by Sir
Arthur Conan Doyle, in a Sherlock Holmes story:
Gregory (a Scotland Yard detective):
"Is there any other point to which you would wish to draw my attention?"
Holmes:
"To the curious incident of the dog in the night-time."
Gregory:
"The dog did nothing in the night-time."
Holmes:
"That was the curious incident."
The mathematical community would have no reason to complain about changes made
to the size of U+2218 (=composition function), because they’re using Latex and
\circ, remaining oblivious of changes in Unicode.
And if only one person has commented on the contradiction between Table 2.5 and
its associated text, that suggests something about the relevance of (that part
of) UTR 25 to the world at large.
And at the end you still have to add a new XL size which is not part of TR25.
correct -- that new XL size cannot (normally) be part of the graduated
series, if the large size is big enough to enclose a letter, and the new XL
square is not to exceed the size of the EM quad.
I also looked at the current font implementations of squares and they are all
over the place in relative sizes but all have bigger sizes than what you
propose. By far the more consistent set is the Wingdings set, but there are
some many size inter correlations in geometric shapes that I can’t just put
them in the charts. What I have found consistently among implemented fonts is a
large gap between ‘small’ and ‘very small’ which reinforce my introduction of
‘slightly small’.
>
You are so right about relative sizes being "all over the place", and for this
very reason, the actual glyph sizes used by existing fonts should not be used
to justify new columns in Table 2.5 (without evidence of usage).
I don't recall proposing any actual sizes, just that anybody
seeking to implement a full set of circles, say, which meets
the explicit and implicit requirements of UTR 25, will come up
with a similar set of dimensions to those that I use.
What I did propose, after measuring the glyphs used in
Wingdings/Webdings, was an existing size category which each
Wingdings shape could be slotted into.
Another goal was to take into consideration existing practice among math
fonts.
>
Things may have changed in the last year, of course, but last time I checked
Stix v0.9 was all over the place, Stix v1.0 is a lot, lot, better, but the
avowedly "mathematical" fonts (such as Asana and Cambria) didn't bother much
with abstract shapes. Much better coverage was provided by the completist fonts
(Code2000, Déjà Vu, Freefont and MS Mincho).
As demonstrated elsewhere, all the Wingdings shapes can be accommodated within
the existing set of sizes, in a manner entirely consistent with both Table 2.5
and the Wingdings glyphs themselves. Add to that
-- the low level of interest,
-- the low level of implementation, and
-- the absence of attested established usage,
and it is difficult to see why we would need more sizes in the shape table.
And once the Wingdings characters have been added to Table 2.5 (where
relevant), it is difficult to see how anyone would justify filling in the gaps,
without evidence of usage. As we are occasionally reminded on this list,
consistency and completeness alone are not sufficient reasons for inclusion in
TUS.
regards . . . /phil chastney
Links:
UTR 25, ver 13 http://www.unicode.org/reports/tr25/
Shapes II http://www.chastney.com/~philip/shapes/shapes_02.pdf
Notes:
(i) mathematically, "graduation" (or "gradation", depending on your
preferred variety of English) has 2 slightly different meanings: a "graduated
set" may just be a set ordered on some value, but here it has the rather more
specific
meaning of a set of equally spaced values of a "smooth" function
(ii) on this list, "completist" is sometimes used as a derogatory term --
it is not intended to be derogatory here
