===================================================================
RCS file: /cvs/mandoc/mandoc_html.3,v
retrieving revision 1.2
retrieving revision 1.9
diff -u -p -r1.2 -r1.9
--- mandoc/mandoc_html.3	2017/01/17 01:47:51	1.2
+++ mandoc/mandoc_html.3	2017/07/14 16:06:44	1.9
@@ -1,6 +1,6 @@
-.\"	$Id: mandoc_html.3,v 1.2 2017/01/17 01:47:51 schwarze Exp $
+.\"	$Id: mandoc_html.3,v 1.9 2017/07/14 16:06:44 schwarze Exp $
 .\"
-.\" Copyright (c) 2014 Ingo Schwarze <schwarze@openbsd.org>
+.\" Copyright (c) 2014, 2017 Ingo Schwarze <schwarze@openbsd.org>
 .\"
 .\" Permission to use, copy, modify, and distribute this software for any
 .\" purpose with or without fee is hereby granted, provided that the above
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: January 17 2017 $
+.Dd $Mdocdate: July 14 2017 $
 .Dt MANDOC_HTML 3
 .Os
 .Sh NAME
@@ -48,6 +48,14 @@
 .Fa "struct html *h"
 .Fa "const char *word"
 .Fc
+.Ft char *
+.Fo html_make_id
+.Fa "const struct roff_node *n"
+.Fc
+.Ft int
+.Fo html_strlen
+.Fa "const char *cp"
+.Fc
 .Sh DESCRIPTION
 The mandoc HTML formatter is not a formal library.
 However, as it is compiled into more than one program, in particular
@@ -137,15 +145,43 @@ Most attributes require one
 .Va char *
 argument which becomes the value of the attribute.
 The arguments have to be given in the same order as the attribute letters.
+If an argument is
+.Dv NULL ,
+the respective attribute is not written.
 .Bl -tag -width 1n -offset indent
 .It Cm c
 Print a
 .Cm class
 attribute.
+This attribute letter can optionally be followed by the modifier letter
+.Cm T .
+In that case, a
+.Cm title
+attribute with the same value is also printed.
 .It Cm h
 Print a
 .Cm href
 attribute.
+This attribute letter can optionally be followed by a modifier letter.
+If followed by
+.Cm R ,
+it formats the link as a local one by prefixing a
+.Sq #
+character.
+If followed by
+.Cm I ,
+it interpretes the argument as a header file name
+and generates a link using the
+.Xr mandoc 1
+.Fl O Cm includes
+option.
+If followed by
+.Cm M ,
+it takes two arguments instead of one, a manual page name and
+section, and formats them as a link to a manual page using the
+.Xr mandoc 1
+.Fl O Cm man
+option.
 .It Cm i
 Print an
 .Cm id
@@ -155,18 +191,20 @@ Print an arbitrary attribute.
 This format letter requires two
 .Vt char *
 arguments, the attribute name and the value.
+The name must not be
+.Dv NULL .
 .It Cm s
 Print a
 .Cm style
 attribute.
 If present, it must be the last format letter.
 In contrast to the other format letters, this one does not yet
-print the value and does not require an argument.
+print the value and does not take an argument.
 Instead, the rest of the format string consists of pairs of
 argument type letters and style name letters.
 .El
 .Pp
-Argument type letters each require on argument as follows:
+Argument type letters each require one argument as follows:
 .Bl -tag -width 1n -offset indent
 .It Cm h
 Requires one
@@ -181,25 +219,31 @@ argument, used as a style value.
 Requires one
 .Vt struct roffsu *
 argument, used as a length.
-.It Cm v
-Requires one
-.Vt int
-argument, interpreted as a vertical length in units of
-.Dv SCALE_VS .
 .It Cm w
 Requires one
 .Vt char *
 argument, interpreted as an
 .Xr mdoc 7 Ns -style
 width specifier.
+If the argument is
+.Dv NULL ,
+nothing is printed for this pair.
+.Pp
+The
+.Cm w
+argument type letter can optionally be followed by one or two
+modifier letters.
+The modifier
+.Cm +
+increases the width by 10% to make even bold text fit
+and adds two units for padding between columns.
+The modifier
+.Cm \-
+makes the width negative by multiplying it with \-1.
 .El
 .Pp
 Style name letters decide what to do with the preceding argument:
 .Bl -tag -width 1n -offset indent
-.It Cm b
-Set
-.Cm margin-bottom
-to the given length.
 .It Cm h
 Set
 .Cm height
@@ -212,10 +256,6 @@ to the given length.
 Set
 .Cm margin-left
 to the given length.
-.It Cm t
-Set
-.Cm margin-top
-to the given length.
 .It Cm w
 Set
 .Cm width
@@ -231,12 +271,12 @@ requires two
 .Vt char *
 arguments.
 The first is the style name, the second its value.
+The style name must not be
+.Dv NULL .
 .El
 .Pp
 .Fn print_otag
 uses the private function
-.Fn print_attr
-which in turn uses the private function
 .Fn print_encode
 to take care of HTML encoding.
 If required by the element type, it remembers in
@@ -269,30 +309,27 @@ and
 .Fn print_tagq
 functions.
 .Pp
-The functions
-.Fn bufinit ,
-.Fn bufcat* ,
-and
-.Fn buffmt*
-do not directly produce output but buffer text in the
-.Fa buf
-member of
-.Fa h .
-They are not used internally by
-.Pa html.c
-but intended for use by the language-specific formatters
-to ease preparation of strings for the
-.Fa p
-argument of
-.Fn print_otag
-and for the
-.Fa word
-argument of
-.Fn print_text .
-Consequently, these functions do not do any HTML encoding.
+The function
+.Fn html_make_id
+takes a node containing one or more text children
+and returns a newly allocated string containing the concatenation
+of the child strings, with blanks replaced by underscores.
+If the node
+.Fa n
+contains any non-text child node,
+.Fn html_make_id
+returns
+.Dv NULL
+instead.
+The caller is responsible for freeing the returned string.
 .Pp
+The function
+.Fn html_strlen
+counts the number of characters in
+.Fa cp .
+It is used as a crude estimate of the width needed to display a string.
+.Pp
 The functions
-.Fn html_strlen ,
 .Fn print_eqn ,
 .Fn print_tbl ,
 and
@@ -340,5 +377,6 @@ implementation of common mandoc utility functions
 .An -nosplit
 The mandoc HTML formatter was written by
 .An Kristaps Dzonsons Aq Mt kristaps@bsd.lv .
-This manual was written by
-.An Ingo Schwarze Aq Mt schwarze@openbsd.org .
+It is maintained by
+.An Ingo Schwarze Aq Mt schwarze@openbsd.org ,
+who also wrote this manual.