[pdftex] Spacing problem on imagesetter

[Martin Schroeder]

On 2002-07-03 18:28:30 +0200, Ulrich Dirr wrote:
> 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.

Best regards
        Martin
-- 
               Martin Schröder, MS at ArtCom-GmbH.DE
          ArtCom GmbH, Grazer Straße 8, D-28359 Bremen
          Voice +49 421 20419-44 / Fax +49 421 20419-10