24018: add zcurses scroll

3 files changed, 64 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 336cd89ff..3ca6f3f0b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2007-10-24  Peter Stephenson  <p.w.stephenson@ntlworld.com>
 
+	* 24018: Doc/Zsh/mod_curses.yo, Src/Modules/curses.c:
+	add "zcurses scroll".
+
 	* 24017: Doc/Zsh/mod_curses.yo, Src/Modules/curses.c:
 	fold color support into attr subcommand and improve error
 	handling; add various readonly parameters; replace strtok();
diff --git a/Doc/Zsh/mod_curses.yo b/Doc/Zsh/mod_curses.yo
index a7101f543..b902fce90 100644
--- a/Doc/Zsh/mod_curses.yo
+++ b/Doc/Zsh/mod_curses.yo
@@ -18,7 +18,8 @@ xitem(tt(zcurses) tt(move) var(targetwin) var(new_y) var(new_x) )
 xitem(tt(zcurses) tt(char) var(targetwin) var(character) )
 xitem(tt(zcurses) tt(string) var(targetwin) var(string) )
 xitem(tt(zcurses) tt(border) var(targetwin) var(border) )(
-item(tt(zcurses) tt(attr) var(targetwin) [ var({+/-}attribute) | var(fg_col)tt(/)var(bg_col) ] [...])(
+xitem(tt(zcurses) tt(attr) var(targetwin) [ var({+/-}attribute) | var(fg_col)tt(/)var(bg_col) ] [...])
+item(tt(zcurses) tt(scroll) [ tt(on) | tt(off) | {+/-}var(lines) ])(
 Manipulate curses windows.  All uses of this command should be
 bracketed by `tt(zcurses init)' to initialise use of curses, and
 `tt(zcurses end)' to end it; omitting `tt(zcurses end)' can cause
@@ -53,6 +54,15 @@ supported are tt(blink), tt(bold), tt(dim), tt(reverse), tt(standout),
 and tt(underline).  Each var(fg_col)tt(/)var(bg_col) (to be read as
 `var(fg_col) on var(bg_col)') sets the foreground and background color
 for character output.
+
+tt(scroll) can be used with tt(on) or tt(off) to enabled or disable
+scrolling of a window when the cursor would otherwise move below the
+window due to typing or output.  It can also be used with a positive
+or negative integer to scroll the window up or down the given number
+of lines without changing the current cursor position (which therefore
+appears to move in the opposite direction relative to the window).
+In the second case, if scrolling is tt(off) it is temporarily turned tt(on)
+to allow the window to be scrolled,
 )
 enditem()
 
diff --git a/Src/Modules/curses.c b/Src/Modules/curses.c
index de9173b9e..06ad463e1 100644
--- a/Src/Modules/curses.c
+++ b/Src/Modules/curses.c
@@ -51,9 +51,15 @@
 
 #include <stdio.h>
 
+enum zc_win_flags {
+    /* Scrolling enabled */
+    ZCWF_SCROLL = 0x0001
+};
+
 typedef struct zc_win {
     WINDOW *win;
     char *name;
+    int flags;
 } *ZCWin;
 
 struct zcurses_namenumberpair {
@@ -620,6 +626,49 @@ zccmd_attr(const char *nam, char **args)
 }
 
 
+static int
+zccmd_scroll(const char *nam, char **args)
+{
+    LinkNode node;
+    ZCWin w;
+    int ret = 0;
+
+    node = zcurses_validate_window(args[0], ZCURSES_USED);
+    if (node == NULL) {
+	zwarnnam(nam, "%s: %s", zcurses_strerror(zc_errno), args[0]);
+	return 1;
+    }
+
+    w = (ZCWin)getdata(node);
+
+    if (!strcmp(args[1], "on")) {
+	if (scrollok(w->win, TRUE) == ERR)
+	    return 1;
+	w->flags |= ZCWF_SCROLL;
+    } else if (!strcmp(args[1], "off")) {
+	if (scrollok(w->win, FALSE) == ERR)
+	    return 1;
+	w->flags &= ~ZCWF_SCROLL;
+    } else {
+	char *endptr;
+	zlong sl = zstrtol(args[1], &endptr, 10);
+	if (*endptr) {
+	    zwarnnam(nam, "scroll requires `on', `off' or integer: %s",
+		     args[1]);
+	    return 1;
+	}
+	if (!(w->flags & ZCWF_SCROLL))
+	    scrollok(w->win, TRUE);
+	if (wscrl(w->win, (int)sl) == ERR)
+	    ret = 1;
+	if (!(w->flags & ZCWF_SCROLL))
+	    scrollok(w->win, FALSE);
+    }
+
+    return ret;
+}
+
+
 /*********************
   Main builtin handler
  *********************/
@@ -643,6 +692,7 @@ bin_zcurses(char *nam, char **args, Options ops, UNUSED(int func))
 	{"border", zccmd_border, 1, 1},
 	{"end", zccmd_endwin, 0, 0},
 	{"attr", zccmd_attr, 2, -1},
+	{"scroll", zccmd_scroll, 2, 2},
 	{NULL, (zccmd_t)0, 0, 0}
     };