[groff] 06/06: [docs]: Further clarify "text font" concept.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 482926aaa9a597f2410c721478ccd36dc8289335
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Sun Jun 11 00:01:33 2023 -0500

    [docs]: Further clarify "text font" concept.
    
    * Explicitly point out what's weird about ZCMI.
    * Use italics instead of scare quotes for "graphic rendition" jargon.
    * Add concept index entries to our Texinfo manual.
---
 doc/groff.texi  | 15 ++++++++++-----
 man/groff.7.man |  7 +++++--
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/doc/groff.texi b/doc/groff.texi
index 6b4d77a1a..c70369bf3 100644
--- a/doc/groff.texi
+++ b/doc/groff.texi
@@ -10087,10 +10087,10 @@ typefaces into @dfn{families} containing each of these
 styles.@footnote{Font designers prepare families such that the styles
 share esthetic properties.}  A @dfn{text font} is thus often a family
 combined with a style, but it need not be:@: consider the @code{ps} and
-@code{pdf} devices' @code{ZCMI} (Zapf Chancery Medium italic).  On
-typesetting devices, at least one @dfn{special font} is available,
-comprising @dfn{unstyled} glyphs for mathematical operators and other
-purposes.
+@code{pdf} devices' @code{ZCMI} (Zapf Chancery Medium italic)---often,
+no other style of Zapf Chancery Medium is provided.  On typesetting
+devices, at least one @dfn{special font} is available, comprising
+@dfn{unstyled} glyphs for mathematical operators and other purposes.
 
 @cindex font description file
 @cindex description file, font
@@ -10136,9 +10136,14 @@ mounting position, and therefore style, is always 
@samp{1} (@samp{R}).
 By issuing appropriate formatter instructions, you can override these
 defaults before your document writes its first glyph.
 
+@cindex graphic renditions
+@cindex renditions, graphic
+@cindex character cell attributes
+@cindex attributes, character cell
+@cindex cell, character, attributes
 Terminal output devices cannot change font families and lack special
 fonts.  They support style changes by overstriking, or by altering
-ISO@tie{}6429/ECMA-48 ``graphic renditions'' (character cell
+ISO@tie{}6429/ECMA-48 @dfn{graphic renditions} (character cell
 attributes).
 @c END Keep (roughly) parallel with section "Using fonts" of groff(7).
 
diff --git a/man/groff.7.man b/man/groff.7.man
index 209706b54..820f02442 100644
--- a/man/groff.7.man
+++ b/man/groff.7.man
@@ -6623,7 +6623,9 @@ and
 .B pdf
 devices'
 .B ZCMI
-(Zapf Chancery Medium italic).
+(Zapf Chancery Medium italic)\[em]\c
+often,
+no other style of Zapf Chancery Medium is provided.
 .
 On typesetting devices,
 at least one
@@ -6726,7 +6728,8 @@ Terminal output devices cannot change font families and 
lack special
 fonts.
 .
 They support style changes by overstriking,
-or by altering ISO\~6429/\:ECMA-48 \[lq]graphic renditions\[rq]
+or by altering ISO\~6429/\:ECMA-48
+.I "graphic renditions"
 (character cell attributes).
 .\" END Keep (roughly) parallel with groff.texi node "Using Fonts".
 .