add_wch, wadd_wch, mvadd_wch, mvwadd_wch, echo_wchar, wecho_wchar - add
- a complex character and rendition to a curses window, then advance the
- cursor
+ a curses complex character to a window and advance the cursor
- The add_wch, wadd_wch, mvadd_wch, and mvwadd_wch functions put the
- complex character wch into the given window at its current position,
- which is then advanced. These functions perform wrapping and special-
+ The add_wch, wadd_wch, mvadd_wch, and mvwadd_wch functions put the
+ complex character wch into the given window at its current position,
+ which is then advanced. These functions perform wrapping and special-
character processing as follows:
- o If wch refers to a spacing character, then any previous character
- at that location is removed. A new character specified by wch is
- placed at that location with rendition specified by wch. The
- cursor then advances to the next spacing character on the screen.
+ o If wch refers to a spacing character, then any previous character
+ at that location is removed. A new character specified by wch is
+ placed at that location with rendition specified by wch. The
+ cursor then advances after this spacing character, to prepare for
+ writing the next character on the screen.
- o If wch refers to a non-spacing character, all previous characters
- at that location are preserved. The non-spacing characters of wch
- are added to the spacing complex character, and the rendition
- specified by wch is ignored.
+ The newly added spacing character is the base of the active complex
+ character. Subsequent non-spacing characters can be combined with
+ this base until another spacing character is written to the screen,
+ or the cursor is moved, e.g., using wmove.
+
+ o If wch refers to a non-spacing character, it is appended to the
+ active complex character, retaining the previous characters at that
+ location. The rendition specified by wch is ignored.
+
+ The cursor is not advanced after adding a non-spacing character.
+ Subsequent calls to add non-spacing characters will update the same
+ position.
o If the character part of wch is a tab, newline, backspace or other
control character, the window is updated and the cursor moves as if
@@ -102,80 +111,82 @@
lines and other frequently used special characters. These symbols
correspond to the same VT100 line-drawing set as addch(3x).
- ACSUnicodeASCIIacscGlyph
- NameDefaultDefaultcharName
+ UnicodeASCIIacsc
+
+
+ ACSNameDefaultDefaultCharGlyphName
------------------------------------------------------------------------
- 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
-
- The wide-character configuration of ncurses also defines symbols for
+ 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
+
+ The wide-character configuration of ncurses also defines symbols for
thick lines (acsc "J" to "V"):
- ACSUnicodeASCIIacscGlyph
- NameDefaultDefaultcharName
- -----------------------------------------------------------------------
- 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
+ UnicodeASCIIacsc
+ ACSNameDefaultDefaultCharGlyphName
+ ------------------------------------------------------------------------
+ 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
and for double-lines (acsc "A" to "I"):
- ACSUnicodeASCIIacscGlyph
- NameDefaultDefaultcharName
+ UnicodeASCIIacsc
+ ACSNameDefaultDefaultCharGlyphName
------------------------------------------------------------------------
- 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
+ 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
Unicode's descriptions for these characters differs slightly from
- ncurses, by introducing the term "light" (along with less important
+ ncurses, by introducing the term "light" (along with less important
details). Here are its descriptions for the normal, thick, and double
horizontal lines:
@@ -200,7 +211,7 @@
o If scrollok(3x) 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
+ not possible to wrap to a new line.
o 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
@@ -216,18 +227,20 @@
- 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.
+ These functions are described in the XSI Curses standard, Issue 4. The
+ defaults specified for line-drawing characters apply in the POSIX
+ locale.
+
+
X/Open Curses makes it clear that the WACS_ symbols should be defined
as a pointer to cchar_t data, e.g., in the discussion of border_set. A
few implementations are problematic:
o NetBSD curses defines the symbols as a wchar_t within a cchar_t.
- o HPUX curses equates some of the ACS_ symbols to the analogous WACS_
- symbols as if the ACS_ symbols were wide characters. The
+ o HP-UX curses equates some of the ACS_ symbols to the analogous
+ WACS_ symbols as if the ACS_ symbols were wide characters. The
misdefined symbols are the arrows and other symbols which are not
used for line-drawing.
@@ -240,17 +253,17 @@
alternate character sets (i.e., the acsc 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
+ Existing implementations of Unix curses (AIX, HP-UX, Solaris) use only
the acsc 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
+ ncurses 5.3 (2002) provided a table of Unicode values to solve these
problems. NetBSD curses incorporated that table in 2010.
In this implementation, the Unicode values are used instead of the
terminal description's acsc mapping as discussed in ncurses(3x) for the
- environment variable NCURSES_NO_UTF8_ACS. In contrast, for the same
- cases, the line-drawing characters described in curs_addch(3x) will use
- only the ASCII default values.
+ environment variable NCURSES_NO_UTF8_ACS. In contrast, for the same
+ cases, the line-drawing characters described in addch(3x) will use only
+ the ASCII default values.
Having Unicode available does not solve all of the problems with line-
drawing for curses:
@@ -284,13 +297,31 @@
and horizontal), and U+2612 (ballot box with x).
+
+ The complex character type cchar_t can store more than one wide
+ character (wchar_t). The X/Open Curses description does not mention
+ this possibility, describing only the cases where wch is a spacing
+ character or a non-spacing character.
+
+ This implementation assumes that wch is constructed using setcchar(3x),
+ and in turn that the result
+
+ o contains at most one spacing character in the beginning of its list
+ of wide characters, and zero or more non-spacing characters or
+
+ o may hold one non-spacing character.
+
+ In the latter case, ncurses adds the non-spacing character to the
+ active (base) spacing character.
+
+