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Re: Round-off errors in metrics & fontinst/finst status...
>At 06:25 AM 97/12/18 +0000, Rebecca and Rowland wrote:
>>And it can be less if the rounding is less than 0.5 - this 0.15mm is
>>more-or-less worst-case. The rms rounding error is something like 0.3, so
>>the typical error with a repeated character will be nearer 0.05%, or 75
>>microns in 150mm; typical error with random characters will be nearer 7.5
>>microns. I'm not inclined to fret over errors of less than 0.1mm across a
>Ah, but even if noticable error only occurs in fixed width fonts and when
>using the same character repetedtly, doesn't it bother you to spoil the
>incredible accuracy that TeX has, just because of some unneeded sloppyness
>in making fonts, or in making metric tables?
Yes, that does bother me. But I like to get things *right*, even down to
error estimates. (What am I saying? *Especially* error estimates - comes
of having a physics degree. I make no apologies for this.)
On the same track: is it only me who gets tremendously irritated by
LaTeX2e's habit of truncating dimensions to the nearest point? Is there
any reason for this anti-social behaviour?
>I might also mention that some DVI processors switch between relative
>and absolute positioning. This means accumulated errors can produce
>a discontinuity at a transtion, not just at the end of the line. This often
>happens were a superscript appears. In this case even a small error
>may be noticeable (0.15mm is 0.5pt)
0.15mm is likely to be noticeable; it's nearer 0.4pt. This is about twice
1/300 inch, so quite clearly resolvable even using a medium resolution
inkjet like my DW520.