DLI Implementation and Reference Guide - Datalogics

5.2 DLI Implementation and Reference Guide
Introduction
Concepts and Facilities: Guide to the DL Pager Composition System
DLI v3.0 has undergone significant enhancements for support of Unicode and of
multibyte character set encodings. With the inclusion of the International
Components for Unicode (ICU), DLI is now able to properly set text in hundreds of
multibyte encodings and all the common Unicode encodings. DLI is now also able to
set text in scripts which flow from right to left (e.g. Arabic), supports the Unicode
BiDirectional algorithm, and features character shaping and glyph combining.
Unicode text composition is also significantly faster and less memory-intensive than
previous DLI Unicode implementations.
NOTE: The previous support for Unicode, as introduced in DLI v2.2, has been
phased out and is no longer available.
There are two components to this support:
• Enhancements to the DLPDFFONT functionality
• A new DLPDFTEXT structure
To use these enhancements, fonts must be explicitly loaded into the DLPDFINSTANCE
for a job; once loaded, they are available to all documents created with the
DLPDFINSTANCE. The fonts are used to set text (in Unicode or multibyte encodings)
into a DLPDFTEXT area. The text in the DLPDFTEXT area is stored in Unicode UCS-2
format (in host-order endianness), and may be manipulated or extracted. The
DLPDFTEXT is placed into a DLPDFCONTENT area, to place the text into the PDF
content area. Text is written to the PDF file in UCS-2 big-endian format whenever
possible. All fonts loaded are automatically subset to ensure proper output in
generated PDF documents.
Please see information on the DLI sample “WideText” on page 17.21 for a
demonstration of how to use the new DLI font and text functions to typeset Unicode
and multibyte text.