PostScript format to create embedded chars in PDF

Thread View: adobe.pdf.workflow

2 messages

[T] Back to Threads [V] Tree View [G] Group Articles

2 total messages Started by rigvinod Wed, 20 Sep 2006 06:24

#521

Author: rigvinod
Date: Wed, 20 Sep 2006 06:24

33 lines
2086 bytes

In a discussion in the OpenType List Eric Muller showed that PDF already has mechanisms to embed complex text and the corresponding glyphs.

Let me repost Eric Muller's message here:
-------- begin Eric's message------
OpenType list address: opentype-list@indx.co.uk

Vinod Kumar wrote: 

      Meanwhile, Standards for embedding characters in the PDF/PostScript files
      for reverse mapping can be finalized too. Already there for PDF. It's
      of the form









This is documented in section 10.8.3 of the PDF reference, p871.

Check <http://udhrinunicode.org/assemblies/first_article_subset.pdf> for
an extensive use, to the point where copy/paste from Acrobat of those
two pages is almost correct (there is just Acrobat inserting some extra
spaces around such marked content fragments, hopefully to be fixed soon).

I am not familiar with PostScript to speak about that.
---------------end of Eric's message----

I checked the Universal Declaration of Human Rights (first_article*.pdf) and Acroread is able to search for Devanagari text strings as well as Copy and Paste from the PDF into html files in Mozilla composer.It works beautifully.

Now the question. IndiX tools generate PostScript files from plane Indic text files or from html containing Indic text. What is the format of the PostScript file so that the "BMC <</ActualText (characters)>> (glyphs) Tj EMC" lines will be generated in the PDF file when a transformer like ps2pdf is used?

Re: PostScript format to create embedded chars in PDF

#522

Author: rigvinod
Date: Wed, 20 Sep 2006 10:26

10 lines
1304 bytes

While copying and pasting from Eric's message a line disappeared.

-------missed line---
Already there for PDF. It's of the form

BMC <</ActualText (characters)>> (glyphs) Tj EMC

----end of missed lines---

The idea behind this construct is enble Search and Copy and Paste on complex text that do not have a one to one mapping from characters to glyphs. For such scripts, the forward mapping from n chars to m glyphs is carried out by a complicated transformation. The reverse transformation is much more complicated and the BMC..EMC construct is an alternate solution.

Thread Navigation

This is a paginated view of messages in the thread with full content displayed inline.

Messages are displayed in chronological order, with the original post highlighted in green.

Use pagination controls to navigate through all messages in large threads.

Back to All Threads