X-Git-Url: https://ncurses.scripts.mit.edu/?p=ncurses.git;a=blobdiff_plain;f=man%2Fcurs_add_wch.3x;h=245cc17e0cae8c15362d7109a61b8108e064e9f8;hp=8d5d640a4aa9d8eda2e1cfe5071f3512c5c29082;hb=96a4663880a73a00b11700da8a404fdd56833925;hpb=0ac2306dd3aaab1338d8b1458c15a7e476cfc3ff

diff --git a/man/curs_add_wch.3x b/man/curs_add_wch.3x
index 8d5d640a..245cc17e 100644
--- a/man/curs_add_wch.3x
+++ b/man/curs_add_wch.3x
@@ -1,5 +1,5 @@
 .\"***************************************************************************
-.\" Copyright (c) 2001-2006,2010 Free Software Foundation, Inc.              *
+.\" Copyright (c) 2001-2017,2019 Free Software Foundation, Inc.              *
 .\"                                                                          *
 .\" Permission is hereby granted, free of charge, to any person obtaining a  *
 .\" copy of this software and associated documentation files (the            *
@@ -26,10 +26,15 @@
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"
-.\" $Id: curs_add_wch.3x,v 1.9 2010/09/18 20:18:34 tom Exp $
+.\" $Id: curs_add_wch.3x,v 1.25 2019/10/27 00:07:13 tom Exp $
 .TH curs_add_wch 3X ""
+.ie \n(.g .ds `` \(lq
+.el       .ds `` ``
+.ie \n(.g .ds '' \(rq
+.el       .ds '' ''
 .de bP
-.IP \(bu 4
+.ie n  .IP \(bu 4
+.el    .IP \(bu 2
 ..
 .SH NAME
 \fBadd_wch\fP,
@@ -55,6 +60,7 @@
 .B "int wecho_wchar( WINDOW *\fIwin\fP, const cchar_t *\fIwch\fB );"
 .br
 .SH DESCRIPTION
+.SS add_wch
 .PP
 The
 \fBadd_wch\fP,
@@ -83,12 +89,13 @@ and the rendition specified by \fIwch\fP is ignored.
 If the character part of \fIwch\fP is
 a tab, newline, backspace or other control character,
 the window is updated and the cursor moves as if \fBaddch\fR were called.
+.SS echo_wchar
 .PP
 The \fBecho_wchar\fP
 function is functionally equivalent to a call to
 \fBadd_wch\fP
 followed by a call to
-\fBrefresh\fP.
+\fBrefresh\fP(3X).
 Similarly, the
 \fBwecho_wchar\fP
 is functionally equivalent to a call to
@@ -99,11 +106,112 @@ The knowledge
 that only a single character is being output is taken into consideration and,
 for non-control characters, a considerable performance gain might be seen
 by using the *\fBecho\fP* functions instead of their equivalents.
-.SH RETURN VALUES
+.SS Line Graphics
+Like \fBaddch\fP(3X),
+\fBaddch_wch\fP accepts symbols which make it simple to draw lines and other
+frequently used special characters.
+These symbols correspond to the same VT100 line-drawing set as
+\fBaddch\fP(3X).
+.PP
+.TS
+l l l l l
+l l l l l
+_ _ _ _ _
+lw(1.5i) lw5 lw5 lw5 lw20.
+\fBACS\fR	\fBUnicode\fP	\fBASCII\fR	\fBacsc\fP	\fBGlyph\fR
+\fBName\fR	\fBDefault\fP	\fBDefault\fR	\fBchar\fP	\fBName\fR
+WACS_BLOCK	0x25ae 	#	0	solid square block
+WACS_BOARD	0x2592 	#	h	board of squares
+WACS_BTEE	0x2534 	+	v	bottom tee
+WACS_BULLET	0x00b7 	o	~	bullet
+WACS_CKBOARD	0x2592 	:	a	checker board (stipple)
+WACS_DARROW	0x2193 	v	.	arrow pointing down
+WACS_DEGREE	0x00b0 	'	f	degree symbol
+WACS_DIAMOND	0x25c6 	+	`	diamond
+WACS_GEQUAL	0x2265 	>	>	greater-than-or-equal-to
+WACS_HLINE	0x2500 	\-	q	horizontal line
+WACS_LANTERN	0x2603 	#	i	lantern symbol
+WACS_LARROW	0x2190 	<	,	arrow pointing left
+WACS_LEQUAL	0x2264 	<	y	less-than-or-equal-to
+WACS_LLCORNER	0x2514 	+	m	lower left-hand corner
+WACS_LRCORNER	0x2518 	+	j	lower right-hand corner
+WACS_LTEE	0x2524 	+	t	left tee
+WACS_NEQUAL	0x2260 	!	|	not-equal
+WACS_PI	0x03c0 	*	{	greek pi
+WACS_PLMINUS	0x00b1 	#	g	plus/minus
+WACS_PLUS	0x253c 	+	n	plus
+WACS_RARROW	0x2192 	>	+	arrow pointing right
+WACS_RTEE	0x251c 	+	u	right tee
+WACS_S1	0x23ba 	\-	o	scan line 1
+WACS_S3	0x23bb 	\-	p	scan line 3
+WACS_S7	0x23bc 	\-	r	scan line 7
+WACS_S9	0x23bd 	\&_	s	scan line 9
+WACS_STERLING	0x00a3 	f	}	pound-sterling symbol
+WACS_TTEE	0x252c 	+	w	top tee
+WACS_UARROW	0x2191  	^	\-	arrow pointing up
+WACS_ULCORNER	0x250c 	+	l	upper left-hand corner
+WACS_URCORNER	0x2510 	+	k	upper right-hand corner
+WACS_VLINE	0x2502 	|	x	vertical line
+.TE
+.PP
+The wide-character configuration of ncurses also defines symbols
+for thick lines (\fBacsc\fP \*(``J\*('' to \*(``V\*(''):
+.TS
+l l l l l
+l l l l l
+_ _ _ _ _
+lw(1.5i) lw5 lw5 lw5 lw20.
+\fBACS\fR	\fBUnicode\fP	\fBASCII\fR	\fBacsc\fP	\fBGlyph\fR
+\fBName\fR	\fBDefault\fP	\fBDefault\fR	\fBchar\fP	\fBName\fR
+WACS_T_BTEE	0x253b	+	V	thick tee pointing up
+WACS_T_HLINE	0x2501	-	Q	thick horizontal line
+WACS_T_LLCORNER	0x2517	+	M	thick lower left corner
+WACS_T_LRCORNER	0x251b	+	J	thick lower right corner
+WACS_T_LTEE	0x252b	+	T	thick tee pointing right
+WACS_T_PLUS	0x254b	+	N	thick large plus
+WACS_T_RTEE	0x2523	+	U	thick tee pointing left
+WACS_T_TTEE	0x2533	+	W	thick tee pointing down
+WACS_T_ULCORNER	0x250f	+	L	thick upper left corner
+WACS_T_URCORNER	0x2513	+	K	thick upper right corner
+WACS_T_VLINE	0x2503	|	X	thick vertical line
+.TE
+.PP
+and for double-lines (\fBacsc\fP \*(``A\*('' to \*(``I\*(''):
+.PP
+.TS
+l l l l l
+l l l l l
+_ _ _ _ _
+lw(1.5i) lw5 lw5 lw5 lw20.
+\fBACS\fR	\fBUnicode\fP	\fBASCII\fR	\fBacsc\fP	\fBGlyph\fR
+\fBName\fR	\fBDefault\fP	\fBDefault\fR	\fBchar\fP	\fBName\fR
+WACS_D_BTEE	0x2569	+	H	double tee pointing up
+WACS_D_HLINE	0x2550	-	R	double horizontal line
+WACS_D_LLCORNER	0x255a	+	D	double lower left corner
+WACS_D_LRCORNER	0x255d	+	A	double lower right corner
+WACS_D_LTEE	0x2560	+	F	double tee pointing right
+WACS_D_PLUS	0x256c	+	E	double large plus
+WACS_D_RTEE	0x2563	+	G	double tee pointing left
+WACS_D_TTEE	0x2566	+	I	double tee pointing down
+WACS_D_ULCORNER	0x2554	+	C	double upper left corner
+WACS_D_URCORNER	0x2557	+	B	double upper right corner
+WACS_D_VLINE	0x2551	|	Y	double vertical line
+.TE
+.PP
+Unicode's descriptions for these characters differs slightly from ncurses,
+by introducing the term \*(``light\*('' (along with less important details).
+Here are its descriptions for the normal, thick, and double horizontal lines:
+.bP
+U+2500 BOX DRAWINGS LIGHT HORIZONTAL
+.bP
+U+2501 BOX DRAWINGS HEAVY HORIZONTAL
+.bP
+U+2550 BOX DRAWINGS DOUBLE HORIZONTAL
+.SH RETURN VALUE
 .PP
 All routines return the integer \fBERR\fR upon failure and \fBOK\fR on success.
 .PP
-Functions with a "mv" prefix first perform a cursor movement using
+Functions with a \*(``mv\*('' prefix first perform a cursor movement using
 \fBwmove\fP, and return an error if the position is outside the window,
 or if the window pointer is null.
 .SH NOTES
@@ -116,13 +224,86 @@ Note that
 may be macros.
 .SH PORTABILITY
 .PP
-All these functions are described in the XSI Curses standard, Issue 4.
-The defaults specified for forms-drawing characters apply in the POSIX locale.
+All of these functions are described in the XSI Curses standard, Issue 4.
+The defaults specified for line-drawing characters apply in the POSIX locale.
 .PP
-XSI documents constants beginning with \fBWACS_\fP which are used for
-line-drawing.
-Those are not currently implemented in \fBncurses\fP.
+X/Open Curses makes it clear that the WACS_ symbols should be defined as
+a pointer to \fBcchar_t\fP data, e.g., in the discussion of \fBborder_set\fR.
+A few implementations are problematic:
+.bP
+NetBSD curses defines the symbols as a \fBwchar_t\fP within a \fBcchar_t\fP.
+.bP
+HPUX curses equates some of the \fIACS_\fP symbols
+to the analogous \fIWACS_\fP symbols as if the \fIACS_\fP symbols were
+wide characters.
+The misdefined symbols are the arrows
+and other symbols which are not used for line-drawing.
+.PP
+X/Open Curses does not define symbols for thick- or double-lines.
+SVr4 curses implementations defined their line-drawing symbols in
+terms of intermediate symbols.
+This implementation extends those symbols, providing new definitions
+which are not in the SVr4 implementations.
+.PP
+Not all Unicode-capable terminals provide support for VT100-style
+alternate character sets (i.e., the \fBacsc\fP capability),
+with their corresponding line-drawing characters.
+X/Open Curses did not address the aspect of integrating Unicode with
+line-drawing characters.
+Existing implementations of Unix curses (AIX, HPUX, Solaris)
+use only the \fBacsc\fP character-mapping to provide this feature.
+As a result, those implementations can only use single-byte line-drawing
+characters.
+Ncurses 5.3 (2002) provided a table of Unicode values to solve these problems.
+NetBSD curses incorporated that table in 2010.
+.PP
+In this implementation, the Unicode values are used instead of the
+terminal description's \fBacsc\fP mapping as discussed in ncurses(3X)
+for the environment variable \fBNCURSES_NO_UTF8_ACS\fP.
+In contrast, for the same cases, the line-drawing characters
+described in \fBcurs_addch\fP(3X) will use only the ASCII default values.
+.PP
+Having Unicode available does not solve all of the problems with
+line-drawing for curses:
+.bP
+The closest Unicode equivalents to the
+VT100 graphics \fIS1\fP, \fIS3\fP, \fIS7\fP and \fIS9\fP
+frequently are not displayed at
+the regular intervals which the terminal used.
+.bP
+The \fIlantern\fP is a special case.
+It originated with the AT&T 4410 terminal in the early 1980s.
+There is no accessible documentation depicting the lantern symbol
+on the AT&T terminal.
+.IP
+Lacking documentation, most readers assume that a \fIstorm lantern\fP
+was intended.
+But there are several possibilities, all with problems.
+.IP
+Unicode 6.0 (2010) does provide two lantern symbols: U+1F383 and U+1F3EE.
+Those were not available in 2002, and are irrelevant since
+they lie outside the BMP and as a result are not generally available
+in terminals.
+They are not storm lanterns, in any case.
+.IP
+Most \fIstorm lanterns\fP have a tapering glass chimney
+(to guard against tipping);
+some have a wire grid protecting the chimney.
+.IP
+For the tapering appearance, \[u2603] U+2603 was adequate.
+In use on a terminal, no one can tell what the image represents.
+Unicode calls it a snowman.
+.IP
+Others have suggested these alternatives:
+\[sc] U+00A7 (section mark),
+\[u0398] U+0398 (theta),
+\[u03A6] U+03A6 (phi),
+\[u03B4] U+03B4 (delta),
+\[u2327] U+2327 (x in a rectangle),
+\[u256C] U+256C (forms double vertical and horizontal), and
+\[u2612] U+2612 (ballot box with x).
 .SH SEE ALSO
+.na
 .PP
 \fBcurses\fR(3X),
 \fBcurs_addch\fR(3X),
@@ -131,9 +312,3 @@ Those are not currently implemented in \fBncurses\fP.
 \fBcurs_outopts\fR(3X),
 \fBcurs_refresh\fR(3X),
 \fBputwc\fR(3)
-.\"#
-.\"# The following sets edit modes for GNU EMACS
-.\"# Local Variables:
-.\"# mode:nroff
-.\"# fill-column:79
-.\"# End: