On 2012/Dec/08 02:34, Michel Suignard wrote:
> From:philip chastney
>> anybody converting a document currently using Wingding fonts to one using
>> Unicode values and Unicode fonts instead, using the transliteration proposed
>> in N 4384, will find their squares somewhat diminished in size (in this
>> case, by one third)
>>
>>this is because the terminology used for "size" in N
4384 is at variance with the terminology used heretofore
in UTR 25
>
>
>No such a thing as a Unicode font. We produce the charts using complicated
>size adjustment and 100s fonts provided by various providers and then anyone
>is free to create their own.
I meant the term "Unicode Fonts" as used here:
http://www.unicode.org/resources/fonts.html
There is nothing normative about relative size. TR25 does some work at
classifying these relative sizes and this is in fact explored in detail in
section 5 of N4384 (that I wrote). N4384 aims at expanding the size set exposed
in TR25 while staying compatible with its principle.
TUS does not list relative sizes among thenormative behaviours, true, but
anyone who draws U+2295 CIRCLED PLUS bigger than U+2A01 N-ARY CIRCLED PLUS
OPERATOR is an idiot, and the font is not compliant with TUS, because the
character identities have not been preserved
TUS does not dictate actual sizes, provided the specified relationship between
glyph sizes is maintained, and that may perhaps be what you meant
>Some reality check with common Math fonts show that they tend to use larger
>size for their geometric shapes than what is presented in the current chart
>(and in TR25). In fact I am now working in harmonizing the rest of the chart
>geometric shapes with the Wingdings set and that may result in some size
>adjustment in future charts. I have been looking at the STIX fonts for
>example. This would in fact solves the concern expressed here by making 25FC
>and 25A0 a tad bigger.
size adjustment of one or two glyphs in an actual font is not an encoding issue
the original msg gave just one example of the sort of anomaly that
results from the introduction, in N 4115, of two entirely
unnecessary distinctions
the story so far is given in
www.chastney.com/~philip/shapes/slightly_small_%28revised%29.pdf
www.chastney.com/~philip/shapes/size_9_centered.pdf
www.chastney.com/~philip/shapes/N4115_an_alternative_encoding.pdf
the arithmetic involved shouldn't challenge the average 12-year old but,
because it's unlikely anybody will bother working through it all, check out the
last page of "N4115_an_alternative_encoding", which shows how Wingdings
shapes can and do, already, fit harmoniously with Table 2.5 from UTR
25
and (assuming "extra large" is not intended to be a graduated size) does so
without needing to expand the size set exposed in UTR 25
this is because the graduation of sizes has a number of implicit
constraints:
(i) the "small" size needs to be big enough to be visible at small
point sizes;
(ii) the "large" size must be less than the font's body height;
(iii) the difference between adjacent sizes needs to be discernible
at, say, 12pt.
this leaves the font designer with just 3 degrees of freedom:
-- the size of the start point
-- the size of the end point
-- the transition from one size to another,
other sizes being obtained by interpolation or extrapolation
if (iv) the "very small" size is somewhere round about the width of
a vertical stem,
and (v) the "regular" size is somewhere about caps height,
there's just the transition function to be decided
the transition function might consist only of a
number of different sized steps, but add in the observations that
(vi) the transition function might as well be smooth, and
(vii) given the preponderance of small sizes, a geometric
progression works well,
there isn't a lot left to do, in the way of design
a font like STIX, which uses a number of different sized steps, will
necessarily (because of the implicit constraints) be within a few
%age points of a GP
/phil chastney
