ncurses 6.2 - patch 20210109

[ncurses.git] / man / curs_add_wch.3x

diff --git a/man/curs_add_wch.3x b/man/curs_add_wch.3x
index 84092dfd54da56040c8d9e248f5080b89c8d8f95..446020839cd19e614ef6f3e9c75b87a5301beb86 100644 (file)
--- a/man/curs_add_wch.3x
+++ b/man/curs_add_wch.3x
@@ -1,5 +1,6 @@
 .\"***************************************************************************
 .\"***************************************************************************

-.\" Copyright (c) 2001-2006,2010 Free Software Foundation, Inc.              *
+.\" Copyright 2019,2020 Thomas E. Dickey                                     *
+.\" Copyright 2001-2015,2017 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            *
 .\"                                                                          *
 .\" Permission is hereby granted, free of charge, to any person obtaining a  *
 .\" copy of this software and associated documentation files (the            *


@@ -26,8 +27,16 @@
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"

-.\" $Id: curs_add_wch.3x,v 1.7 2010/07/31 16:12:01 tom Exp $
+.\" $Id: curs_add_wch.3x,v 1.28 2020/10/17 23:10:38 tom Exp $

 .TH curs_add_wch 3X ""
 .TH curs_add_wch 3X ""

+.ie \n(.g .ds `` \(lq
+.el       .ds `` ``
+.ie \n(.g .ds '' \(rq
+.el       .ds '' ''
+.de bP
+.ie n  .IP \(bu 4
+.el    .IP \(bu 2
+..

 .SH NAME
 \fBadd_wch\fP,
 \fBwadd_wch\fP,
 .SH NAME
 \fBadd_wch\fP,
 \fBwadd_wch\fP,


@@ -46,12 +55,13 @@
 .B "int mvadd_wch( int \fIy\fP, int \fIx\fP, const cchar_t *\fIwch\fB );"
 .br
 .B "int mvwadd_wch( WINDOW *\fIwin\fP, int \fIy\fP, int \fIx\fP, const cchar_t *\fIwch\fB );"
 .B "int mvadd_wch( int \fIy\fP, int \fIx\fP, const cchar_t *\fIwch\fB );"
 .br
 .B "int mvwadd_wch( WINDOW *\fIwin\fP, int \fIy\fP, int \fIx\fP, const cchar_t *\fIwch\fB );"

-.br
+.sp

 .B "int echo_wchar( const cchar_t *\fIwch\fB );"
 .br
 .B "int wecho_wchar( WINDOW *\fIwin\fP, const cchar_t *\fIwch\fB );"
 .br
 .SH DESCRIPTION
 .B "int echo_wchar( const cchar_t *\fIwch\fB );"
 .br
 .B "int wecho_wchar( WINDOW *\fIwin\fP, const cchar_t *\fIwch\fB );"
 .br
 .SH DESCRIPTION

+.SS add_wch

 .PP
 The
 \fBadd_wch\fP,
 .PP
 The
 \fBadd_wch\fP,


@@ -63,32 +73,30 @@ window at its current position,
 which is then advanced.
 These functions perform
 wrapping and special-character processing as follows:
 which is then advanced.
 These functions perform
 wrapping and special-character processing as follows:

-.TP 5
-\-
+.bP

 If \fIwch\fP refers to a spacing character,
 then any previous character at that location is removed.
 A new character specified by \fIwch\fP is
 placed at that location with rendition specified by \fIwch\fP.
 The cursor then advances to
 the next spacing character on the screen.
 If \fIwch\fP refers to a spacing character,
 then any previous character at that location is removed.
 A new character specified by \fIwch\fP is
 placed at that location with rendition specified by \fIwch\fP.
 The cursor then advances to
 the next spacing character on the screen.

-.TP 5
-\-
+.bP

 If \fIwch\fP refers to a non-spacing character,
 all previous characters at that location are preserved.
 The non-spacing characters of \fIwch\fP
 are added to the spacing complex character,
 and the rendition specified by \fIwch\fP is ignored.
 If \fIwch\fP refers to a non-spacing character,
 all previous characters at that location are preserved.
 The non-spacing characters of \fIwch\fP
 are added to the spacing complex character,
 and the rendition specified by \fIwch\fP is ignored.

-.TP 5
-\-
+.bP

 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.
 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
 .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
 Similarly, the
 \fBwecho_wchar\fP
 is functionally equivalent to a call to


@@ -99,9 +107,133 @@ 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.
 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
 All routines return the integer \fBERR\fR upon failure and \fBOK\fR on success.

+.PP
+X/Open does not define any error conditions.
+This implementation returns an error
+.bP
+if the window pointer is null or
+.bP
+if it is not possible to add a complete character in the window.
+.PP
+The latter may be due to different causes:
+.bP
+If \fBscrollok\fR is not enabled,
+writing a character at the lower right margin succeeds.
+However, an error is returned because
+it is not possible to wrap to a new line
+.bP
+If an error is detected when converting a multibyte character to a sequence
+of bytes,
+or if it is not possible to add all of the resulting bytes in the window,
+an error is returned.
+.PP
+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
 .PP
 Note that
 .SH NOTES
 .PP
 Note that


@@ -112,13 +244,86 @@ Note that
 may be macros.
 .SH PORTABILITY
 .PP
 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
+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
 .PP

-XSI documents constants beginning with \fBWACS_\fP which are used for
-line-drawing.
-Those are not currently implemented in \fBncurses\fP.
+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
 .SH SEE ALSO

+.na

 .PP
 \fBcurses\fR(3X),
 \fBcurs_addch\fR(3X),
 .PP
 \fBcurses\fR(3X),
 \fBcurs_addch\fR(3X),


@@ -127,9 +332,3 @@ Those are not currently implemented in \fBncurses\fP.
 \fBcurs_outopts\fR(3X),
 \fBcurs_refresh\fR(3X),
 \fBputwc\fR(3)
 \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: