59 lines
3.7 KiB
XML
59 lines
3.7 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
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<!-- This file is part of the DITA Open Toolkit project. See the accompanying LICENSE file for applicable license. -->
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<concept id="history-pdf-transformation">
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<title>History of the PDF transformation</title>
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<shortdesc>The DITA Open Toolkit PDF transformation was originally based on a third-party contribution by Idiom
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Technologies, and is commonly known as the “pdf2” plug-in.</shortdesc>
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<prolog>
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<metadata>
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<keywords>
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<indexterm><xmlelement>info</xmlelement></indexterm>
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<indexterm>legacypdf</indexterm>
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<indexterm>PDF2
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<index-see>PDF
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<indexterm>plug-in, history of</indexterm></index-see></indexterm>
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<indexterm>languages
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<indexterm>auto-generated strings</indexterm></indexterm>
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<indexterm>PDF
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<indexterm>plug-in, history of</indexterm>
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<indexterm>HTML formatting differences</indexterm></indexterm>
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<indexterm>Idiom Technologies</indexterm>
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<indexterm>HTML
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<indexterm>PDF formatting differences</indexterm></indexterm>
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<indexterm>DITA 1.1</indexterm>
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<indexterm>index
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<indexterm>indexing domain</indexterm></indexterm>
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<indexterm>Customization directory</indexterm>
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<indexterm>org.dita.pdf2</indexterm>
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</keywords>
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</metadata>
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</prolog>
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<conbody>
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<p>When IBM developed the code that later became DITA-OT, it included only a proof-of-concept PDF transformation.
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IBM had their own processing chain for producing PDFs from SGML, which they had developed over several decades, so
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resources were focused primarily on XHTML output and preprocessing.</p>
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<p>Since the initial proof-of-concept transformation was not robust enough for production-grade output, companies
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began to develop their own PDF transformations. One company, Idiom Technologies, made their transformation (known
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as the “pdf2” transformation) available as open source on 23 February 2006. The Idiom plug-in was initially
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available as a separately-downloadable plug-in that could be installed into DITA-OT.</p>
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<p>Later the DITA-OT project formally incorporated the Idiom plug-in as a demonstration in the
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<filepath>demo/fo</filepath> directory. Beginning with DITA-OT version 1.5, released 18 December 2009, the
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“pdf2” code served as the main, supported PDF transformation. (The original PDF transformation was deprecated and
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renamed “legacypdf”.) In DITA-OT version 1.6, the “pdf2” plug-in was moved to
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<filepath>plugins/org.dita.pdf2</filepath>. </p>
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<p>The fact that the current PDF transformation was not originally developed in parallel with the other core DITA-OT
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transformations led to anomalies that often confuse users:</p>
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<ul>
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<li>Elements are often (by default) styled differently in the XHTML and PDF transformations. For example, consider
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the <xmlelement>info</xmlelement> element in a task topic. In HTML output, this is an inline element; in PDF
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output, it is a block-level element.</li>
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<li>The auto-generated strings used for localization are different, and so languages that are supported by DITA-OT
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differ based on whether the XHTML or PDF transformation is used.</li>
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<li>The Idiom plug-in used its own extension mechanism (the <filepath>Customization</filepath> folder) to provide
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overrides to the PDF transformation.</li>
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<li>Before the release of DITA 1.1 (which added support for the indexing domain), Idiom developed an index
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extension that used a FrameMaker-inspired syntax.</li>
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</ul>
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</conbody>
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</concept>
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