Emulate CSR with existing screen data on old/stupid terminals which don't support it.

CHANGES

@@ -1,3 +1,8 @@
+11 February 2009
+
+* Emulate scroll regions (slowly) to support the few terminals which don't have
+  it (some of which don't really have any excuse).
+
 10 February 2009
 
 * No longer redraw the status line every status-interval unless it has actually
@@ -1090,7 +1095,7 @@
   (including mutt, emacs). No status bar yet and no key remapping or other
   customisation.
 
-$Id: CHANGES,v 1.250 2009-02-10 00:18:06 nicm Exp $
+$Id: CHANGES,v 1.251 2009-02-11 19:06:56 nicm Exp $
 
  LocalWords:  showw utf UTF fulvio ciriaco joshe OSC APC gettime abc DEF OA clr
  LocalWords:  rivo nurges lscm Erdely eol smysession mysession ek dstname RB ms

NOTES

@@ -72,14 +72,6 @@ A Vim syntax file is available in the examples directory. To install it:
 - Switch on syntax highlighting in your vimrc file by adding "syntax enable"
   to it.
 
-There are the following known issues:
-
-- cons25 on the FreeBSD console doesn't support scroll region (cs) (or lies
-  about support, I'm not totally clear which). This is a pity but emulating cs
-  is nontrivial and as most modern vt220-based software terminals support it,
-  currently there are better things to work one. Diffs or ideas how to cleanly
-  emulate cs are welcome.
-
 For debugging, running tmux with -v or -vv will generate server and client log
 files in the current directory.
 
@@ -99,4 +91,4 @@ welcome. Please email:
 
 -- Nicholas Marriott <nicm@users.sf.net>
 
-$Id: NOTES,v 1.42 2009-01-18 17:20:52 nicm Exp $
+$Id: NOTES,v 1.43 2009-02-11 19:06:58 nicm Exp $

tty-term.c

@@ -1,4 +1,4 @@
-/* $Id: tty-term.c,v 1.11 2009-02-11 18:44:08 nicm Exp $ */
+/* $Id: tty-term.c,v 1.12 2009-02-11 19:06:58 nicm Exp $ */
 
 /*
  * Copyright (c) 2008 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -240,10 +240,6 @@ tty_term_find(char *name, int fd, char **cause)
 		xasprintf(cause, "terminal does not support ri");
 		goto error;
 	}
-	if (!tty_term_has(term, TTYC_CSR)) {
-		xasprintf(cause, "terminal does not support csr");
-		goto error;
-	}
 	if (!tty_term_has(term, TTYC_CUP)) {
 		xasprintf(cause, "terminal does not support cup");
 		goto error;

tty.c

@@ -1,4 +1,4 @@
-/* $Id: tty.c,v 1.69 2009-02-11 18:44:08 nicm Exp $ */
+/* $Id: tty.c,v 1.70 2009-02-11 19:06:58 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -32,6 +32,7 @@ u_char	tty_get_acs(struct tty *, u_char);
 
 void	tty_emulate_repeat(
     	    struct tty *, enum tty_code_code, enum tty_code_code, u_int);
+void	tty_draw_line(struct tty *, struct window_pane *, u_int);
 
 void	tty_raw(struct tty *, const char *);
 
@@ -368,6 +369,27 @@ tty_emulate_repeat(
 	}
 }
 
+void
+tty_draw_line(struct tty *tty, struct window_pane *wp, u_int py)
+{
+	struct screen		*s = wp->screen;
+	const struct grid_cell	*gc;
+	struct grid_cell	 tc;
+	u_int			 i;
+
+	for (i = 0; i < tty->sx; i++) {
+		gc = grid_view_peek_cell(s->grid, i, py);
+
+ 		tty_cursor(tty, i, py, wp->yoff);
+		if (screen_check_selection(s, i, py)) {
+			memcpy(&tc, &s->sel.cell, sizeof tc);
+			tc.data = gc->data;
+			tty_cell(tty, &tc);
+		} else
+			tty_cell(tty, gc);
+	}
+}
+
 void
 tty_write(struct tty *tty, struct window_pane *wp, enum tty_cmd cmd, ...)
 {
@@ -428,7 +450,22 @@ void
 tty_cmd_insertline(struct tty *tty, struct window_pane *wp, va_list ap)
 {
 	struct screen	*s = wp->screen;
-	u_int		 ua;
+	u_int		 ua, i;
+
+ 	if (!tty_term_has(tty->term, TTYC_CSR)) {
+		/*
+		 * Scroll region unsupported. Redraw using data from screen
+		 * (already updated).
+		 */
+		if (s->old_cy < s->old_rupper || s->old_cy > s->old_rlower) {
+			for (i = s->old_cy; i < screen_size_y(s); i++)
+				tty_draw_line(tty, wp, i);
+		} else {
+			for (i = s->old_rupper; i <= s->old_rlower; i++)
+				tty_draw_line(tty, wp, i);
+		}
+		return;
+	}
 
 	ua = va_arg(ap, u_int);
 
@@ -444,7 +481,22 @@ void
 tty_cmd_deleteline(struct tty *tty, struct window_pane *wp, va_list ap)
 {
 	struct screen	*s = wp->screen;
-	u_int		 ua;
+	u_int		 ua, i;
+
+ 	if (!tty_term_has(tty->term, TTYC_CSR)) {
+		/*
+		 * Scroll region unsupported. Redraw using data from screen
+		 * (already updated).
+		 */
+		if (s->old_cy < s->old_rupper || s->old_cy > s->old_rlower) {
+			for (i = s->old_cy; i < screen_size_y(s); i++)
+				tty_draw_line(tty, wp, i);
+		} else {
+			for (i = s->old_rupper; i <= s->old_rlower; i++)
+				tty_draw_line(tty, wp, i);
+		}
+		return;
+	}
 
 	ua = va_arg(ap, u_int);
 
@@ -514,6 +566,19 @@ void
 tty_cmd_reverseindex(struct tty *tty, struct window_pane *wp, unused va_list ap)
 {
 	struct screen	*s = wp->screen;
+	u_int		 i;
+
+ 	if (!tty_term_has(tty->term, TTYC_CSR)) {
+		/*
+		 * Scroll region unsupported. If would have scrolled, redraw
+		 * scroll region from already updated window screen.
+		 */
+		if (s->old_cy == s->old_rupper) {
+			for (i = s->old_rupper; i <= s->old_rlower; i++)
+				tty_draw_line(tty, wp, i);
+			return;
+		}
+	}
 
 	tty_reset(tty);
 
@@ -527,6 +592,19 @@ void
 tty_cmd_linefeed(struct tty *tty, struct window_pane *wp, unused va_list ap)
 {
 	struct screen	*s = wp->screen;
+	u_int		 i;
+
+ 	if (!tty_term_has(tty->term, TTYC_CSR)) {
+		/*
+		 * Scroll region unsupported. If would have scrolled, redraw
+		 * scroll region from already updated window screen.
+		 */
+		if (s->old_cy == s->old_rlower) {
+			for (i = s->old_rupper; i <= s->old_rlower; i++)
+				tty_draw_line(tty, wp, i);
+			return;
+		}
+	}
 
 	tty_reset(tty);
 
@@ -694,6 +772,8 @@ tty_reset(struct tty *tty)
 void
 tty_region(struct tty *tty, u_int rupper, u_int rlower, u_int oy)
 {
+	if (!tty_term_has(tty->term, TTYC_CSR))
+		return;
 	if (tty->rlower != oy + rlower || tty->rupper != oy + rupper) {
 		tty->rlower = oy + rlower;
 		tty->rupper = oy + rupper;