[Poppler-bugs] [Bug 81748] FreeText annotation ignores font

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=81748

--- Comment #3 from Tobias Deiminger <haxtibal at posteo.de> ---
Thanks Oliver! I've got another patch pending based on yours. It already works
somewhat. But there's something to clarify ahead:

Attachment 103449 seems broken. If that's true we can't use it as reference.

Annot /DA has a Tf operand '/Rufscript'.
 <<
  % ...
  /DA (/Rufscript 18 Tf 0 0 0.5 rg )
  /Subtype /FreeText
 >>

But there's no resource named '/Rufscript' in the font entry of the default
resource dictionary. More over, there's no default resource dictionary at all:

3 0 obj % This is "Interactive Form Dictionary", aka AcroForm
 <<
  % There's no /DR (default resource dictionary) in here!
  /Fields [
    5 0 R
  ]
  /SigFlags 3
 >>
endobj

Obviously the PDF composer (prawnpdf [0]) thought it would be sufficient to
write the name of the font as Tf operand. But that's not true. You need to name
a font resource entry as operand, not the name of a font itself. The font entry
can have an arbitrary name. It's /BaseFont in font dictionary which decides
what font program to use.

Some standard excerpts that make me believe I'm right:
PDF 32000-1:2008 12.5.6.6 Free Text Annotations: "The default appearance string
that shall be used in formatting the text (see 12.7.3.3, “Variable Text”)"
PDF 32000-1:2008 12.7.3.3 Variable Text: "The specified font value shall match
a resource name in the Font entry of the default resource dictionary"

I checked the output of LaTex pdfcomment package [1] and found it misbehaves in
a similar way to attachment 103449. Two different composers misbehaving leaves
me in doubt if I'm right about the non conformance.

Phil says Adobe Reader shows the right font. That's not true for me. When I
open attachment 103449 in Adobe Reader 10, they show a fallback font instead of
Rufscript. Can anyone confirm this?

To go on we have to clarify:
- Is it really out-of-spec if we don't find DAs font tag in the default
resource font dictionary, or is it just me misunderstanding the standard?
- If it is really out-of-spec, shall we consider some heuristics to search the
best font anyway? E.g. search in other resource dictionaries then the default
one (e.g. page resource dictionaries), or use font tag as /BaseFont.
- Or shall we be strict, use some simple default logic in poppler and tell
folks at [0] and [1] about their bug?

[0] https://github.com/prawnpdf/prawn
[1] https://bitbucket.org/kleberj/pdfcomment/wiki/Home

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