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.
+
+ 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, 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.
+ 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
@@ -104,6 +113,7 @@
ACSUnicodeASCIIacscGlyphNameDefaultDefaultcharName
+
------------------------------------------------------------------------
WACS_BLOCK 0x25ae # 0 solid square block
WACS_BOARD 0x2592 # h board of squares
@@ -112,7 +122,6 @@
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
@@ -170,6 +179,7 @@
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
@@ -198,9 +208,9 @@
The latter may be due to different causes:
- o If scrollok 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
+ 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
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
@@ -220,14 +230,16 @@
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 HPUX 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.
@@ -284,13 +296,31 @@
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.
+
+