[pdftex] Spacing problem on imagesetter

[Ulrich Dirr]

> > Everything is ok except of the right part of right-hand pages
> > of the running head. This text which is in small caps is not
> > flushright but seems to produce spurious irregular spaces.
> 
> This could be boiled down to one small test file which showed
> different results in different RIPs. One of the RIP vendors
> (whose RIP showed a different result than Acrobat) when
> questioned provided an explanation:
> 
> <quote>
> The underlying problem is that the PDF contains an embedded font
> in which the glyph widths don't match the glyph widths specified
> in the /Widths array in the font dict.  If I patch the /Widths
> array so that the widths are the same as in the font program
> itself, Acrobat 5 shows the same effect as our RIP.
> 
> Page 317 of the PDF 1.4 manual states that: "These widths must be
> consistent with the actual widths given in the font program
> itself." In this file, they're not. So, you're going to get
> implementation-dependent effects.
> 
> Implementation note 43 in appendix H the PDF 1.4 manual states
> that Acrobat 5 uses the /Widths array for the glyph widths. Our
> RIP is using the T1 font's glyph widths instead of the 
> /Widths array.
> 
> The upshot of which is that the pdf file creator is making
> assumptions about how the file will be rendered and the file
> itself is not in line with the pdf spec.
> </quote>
> 
> So the font is broken (I hope not by pdfTeX), but Acrobat uses a
> work around and many RIPs implement the same work around to be
> compatible with Acrobat.

Very interesting!

How can I check this with FontLab/Fontographer? Or are there different values in the actual font file and the TeX metrics file? (the metrics were generated by FontLab; then from afm to tfm etc.)

Regards,
Ulrich Dirr