Re: wrongly identified geometric shape

From: philip chastney <>
Date: Sun, 16 Dec 2012 10:45:22 -0800 (PST)

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: 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 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
Received on Sun Dec 16 2012 - 12:47:54 CST

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