[tex-live] TL2017's dvipdfmx prints warnings

[Reinhard Kotucha]

On 2018-01-21 at 04:45:56 +0900, Akira Kakuto wrote:

 > Dear Jack,
 > 
 > > According to its manual (and also the top of mathdesign.sty), the
 > > mathdesign package hasn't changed since 2013.  And yet these warnings
 > > didn't appear until TL2017.  So there is something about TL2017 in
 > > particular that is either causing a bug or revealing a latent one.
 > 
 > For example, the character width of
 > character 91 (/bracketleft) from md-gmr8t.tfm and
 > md-gmr8t.pfb is found as:
 > 
 > 375.402 from (CHARWD R 0.375402) in md-gmr8t.tfm
 > 374     from 69 374 hsbw in md-gmr8t.pfb.
 > 
 > If |difference| > 1.0, warning is shown.
 > Please ignore the warning.

There is definitely a severe bug in the current version of xdvipdfmx.

Jack reported:

  xdvipdfmx:warning: Glyph width mismatch for TFM and font (md-gmr8t)
  xdvipdfmx:warning: TFM: 375.402 vs. Type1 font: 374

First of all, let me state that this warning message is extremely
helpful.  It clearly shows what's going wrong.

xdvipdfmx erroneously assumes that values in TFM files are in "big
points".  The obvious solution is to divide values read from a TFM
file by 72.27 and multiply them with 72.

  $ octave -q
  octave:1> 375.402 / 72.27 * 72
  ans =  374.00

I don't know whether DVI files are affected too.  Values therein are
most likely in pt rather than in bp and certainly have to be converted
as well.

Given that xdvipdfmx really assumes that values in TFM and/or DVI
files are in bp, I fear that the PDF output is also incorrect.

Jack, the warning messages will disappear whenever the bug is fixed.

 > If |difference| > 1.0, warning is shown.

The resolution of TeX's fixed point numbers is about a hundredth of
the wavelength of visible light.  Even if we expect rounding errors
somewhere, the threshold of 1bp is much too large in order to detect
any problems at all.

Akira, are you in contact with xdvipdfmx developers?

Regards,
  Reinhard

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