[poppler] Kerning pair information help

[Leonard Rosenthol]

When a font is embedded, there is no requirement that the kerning tables be placed into the PDF (since, as suzuki said, it would NOT be used at rendering time anyway).  In fact, most (all?) PDF production tools remove the kerning tables in order to reduce the size of the embedded font data.

Leonard

From: Steve W <stevew1024 at gmail.com<mailto:stevew1024 at gmail.com>>
Date: Thu, 11 Aug 2011 12:03:51 -0700
To: "poppler at lists.freedesktop.org<mailto:poppler at lists.freedesktop.org>" <poppler at lists.freedesktop.org<mailto:poppler at lists.freedesktop.org>>
Subject: Re: [poppler] Kerning pair information help

Yes, I'm using embedded fonts. I've looked the the pdf itself and  understand that there is no kerning information there.

It looks like some pdf creators automatically break up the text into different groups to handle kerning, but others do not. I'm trying to access the kerning information in the latter case in poppler. I've confirmed that it renders correctly by comparing to adobe acrobat reader, I just need pointed in the right direction regarding the source.

Are there no character pair mappings that contain this information in poppler?

-Steve

2011/8/11 suzuki toshiya <mpsuzuki at hiroshima-u.ac.jp<mailto:mpsuzuki at hiroshima-u.ac.jp>>
Hi Steve,

Excuse me, do you assume that PDF (or embedded font in PDF)
has some kerning information and PDF rendering system should
reflect it?  I'm afraid that PDF itself does not have, and,
embedded font in PDF may have it but they are simply ignored.
If you find some kerning feature that is specified in official
PDF spec and unimplemented in poppler, please let me know.

I guess, PDF production system should tune the glyph positions
strictly, and should not ask PDF rendering systems to reflect
some kerning.

Regards,
mpsuzuki

Steve W wrote:
> I'm new to poppler and am trying to get a grasp of the source code. I'm
> trying to find where the kerning pair information can be accessed via
> poppler. Obviously poppler has access to it somewhere, as font's with
> kerning information are rendered correctly in pdftoppm...
>
> I tried searching for 'kerning' and other related terms, but haven't found
> anything.
>
> I'd greatly appreciate it if someone could point me to the relevant function
> or source file to get met started.
>
> Thanks
> -Steve
>
>
>
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