Différences

Ci-dessous, les différences entre deux révisions de la page.

--- generalites:glossaire:xetex_et_luatex [2018/12/04 00:48] – jejust
+++ 1_generalites:glossaire:xetex_et_luatex [2021/03/20 13:05] (Version actuelle) – Suppression de la page désormais inutile. yannick.tanguy
@@ Ligne 1: / Ligne 1: @@
-====== What are XeTeX and LuaTeX? ======
-The standard [[FAQ-pdftex|pdfTeX]] engine is fully backward-compatible with
-Knuth's TeX. As such, it remains an 8-bit system using specialist [font
-metrics](FAQ-tfm). In contrast, the engines XeTeX and LuaTeX are both
-Unicode-based and able to load standard system (OpenType) fonts. Internally,
-they differ in approach: the same outcomes are reached using very different
-philosophies. There are advantages to the user in each approach.
-===== XeTeX =====
-[[http://scripts.sil.org/xetex|XeTeX]] is a Unicode TeX engine which can load
-system fonts directly using the HarfBuzz library, which is built in. To do
-this, the ''\font'' primitive is extended. In order to support these major
-concepts, a range of TeX primitives are extended. For most LaTeX end users,
-these subtleties are transparent, with the LaTeX kernel and [[ctanpkg>fontspec]]
-package providing interfaces.
-Like Knuth's TeX, it does not directly produce PDF output but rather works
-//via// an intermediate format, XDV (eXtended DVI). Unlike the classical
-[[FAQ-dvi|DVI]] format produced by TeX, XDV files cannot be viewed directly, and
-are normally converted directly to PDF as part of the ''xetex'' run. (The
-conversion itself is carried out by ''xdvpdfmx''.)
-===== LuaTeX =====
-LuaTeX consists of a TeX-like engine with a Lua interpreter "embedded" in it;
-the Lua interpreter has access to many of the data structures used for
-typesetting, so that the programmer may also interpolate chunks of Lua code
-into their (La)TeX macros, or as "call-backs" for use when the TeX-like
-engine does certain operations.
-LuaTeX, like [[FAQ-xetex|XeTeX]], is a Unicode engine and is capable of loading
-system fonts. In contrast to XeTeX, the latter ability is not "built-in" to
-the engine itself, but is added using Lua code. This possibility to modify the
-behaviour of the engine at the "user" end makes it particularly powerful.
-Whilst there are some (deliberate) differences between the behavior of LuaTeX
-and that of Knuth's TeX (or [[FAQ-pdftex|pdfTeX]]), for most users, LuaTeX may
-be used as a drop-in replacement. For most LaTeX end users, the subtleties are
-transparent, with the LaTeX kernel and
-[[ctanpkg>fontspec|fontspec]] package providing interfaces.
-[[FAQ-context|ConTeXt]] Mark 4 (the current version) //requires// LuaTeX:
-this is again transparent to users.
------
-//Source:// [[faquk>FAQ-xetex-luatex|What are XeTeX and LuaTeX?]]
-{{htmlmetatags>metatag-keywords=(LaTeX,UTF8,Unicode,LuaTeX,XeTeX)
-metatag-og:title=(What are XeTeX and LuaTeX?)
-metatag-og:site_name=(FAQ LaTeX francophone)
-}}