2017-07-17 00:26:00

1 files changed, 13 insertions, 1 deletions

diff --git a/doc/context/sources/general/manuals/luatex/luatex-fonts.tex b/doc/context/sources/general/manuals/luatex/luatex-fonts.tex
index 44d913cea..76e7bd108 100644
--- a/doc/context/sources/general/manuals/luatex/luatex-fonts.tex
+++ b/doc/context/sources/general/manuals/luatex/luatex-fonts.tex
@@ -94,6 +94,17 @@ font in \type {font.fonts}. It is the actual expansion factor (a value between
 \type {-shrink} and \type {stretch}, with step \type {step}) of a font that was
 automatically generated by the font expansion algorithm.
 
+Because we store the actual state of expansion with each glyph and don't have
+special font instances, we can change some font related parameters before lines
+are constructed, like:
+
+\starttyping
+font.setexpansion(font.current(),100,100,20)
+\stoptyping
+
+This is mostly meant for experiments (or an optimizing routing written in \LUA)
+so there is no primitive.
+
 The key \type {attributes} can be used to set font attributes in the \PDF\ file.
 The key \type {used} is set by the engine when a font is actively in use, this
 makes sure that the font's definition is written to the output file (\DVI\ or
@@ -472,7 +483,8 @@ parameters to that command. The allowed commands and their arguments are:
 \NC right   \NC 1   \NC number    \NC move right on the page\NC\NR
 \NC special \NC 1   \NC string    \NC output a \type {\special} command\NC\NR
 \NC pdf     \NC 2   \NC 2 strings \NC output a \PDF\ literal, the first string is one of \type {origin},
-                                      \type {page}, \type {direct} or \type {raw}\NC\NR
+                                      \type {page}, \type {direct} or \type {raw}; if you have one string
+                                      only \type {origin} is assumed \NC\NR
 \NC lua     \NC 1   \NC string    \NC execute a \LUA\ script (at \type {\latelua} time)\NC\NR
 \NC image   \NC 1   \NC image     \NC output an image (the argument can be either an \type
                                       {<image>} variable or an \type {image_spec} table)\NC\NR