| .\"*************************************************************************** |
| .\" Copyright 2019,2020 Thomas E. Dickey * |
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| .\" $Id: curs_add_wch.3x,v 1.26 2020/02/02 23:34:34 tom Exp $ |
| .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, |
| \fBmvadd_wch\fP, |
| \fBmvwadd_wch\fP, |
| \fBecho_wchar\fP, |
| \fBwecho_wchar\fP \- add a complex character and rendition to a \fBcurses\fR window, then advance the cursor |
| .SH SYNOPSIS |
| .PP |
| \fB#include <curses.h>\fP |
| .sp |
| .B "int add_wch( const cchar_t *\fIwch\fB );" |
| .br |
| .B "int wadd_wch( WINDOW *\fIwin\fP, const cchar_t *\fIwch\fB );" |
| .br |
| .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 |
| .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, |
| \fBwadd_wch\fP, |
| \fBmvadd_wch\fP, and |
| \fBmvwadd_wch\fP |
| functions put the complex character \fIwch\fP into the given |
| window at its current position, |
| which is then advanced. |
| These functions perform |
| wrapping and special-character processing as follows: |
| .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. |
| .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. |
| .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. |
| .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(3X). |
| Similarly, the |
| \fBwecho_wchar\fP |
| is functionally equivalent to a call to |
| \fBwadd_wch\fP |
| followed by a call to |
| \fBwrefresh\fP. |
| 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. |
| .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 |
| \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 |
| \fBadd_wch\fP, |
| \fBmvadd_wch\fP, |
| \fBmvwadd_wch\fP, and |
| \fBecho_wchar\fP |
| may be macros. |
| .SH PORTABILITY |
| .PP |
| 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 |
| 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), |
| \fBcurs_attr\fR(3X), |
| \fBcurs_clear\fR(3X), |
| \fBcurs_outopts\fR(3X), |
| \fBcurs_refresh\fR(3X), |
| \fBputwc\fR(3) |