Use relative cursor movement instead of absolute when possible and when

supported by the terminal to reduce the size of the output data (generally
about 10-20%).

3 files changed, 134 insertions, 9 deletions

diff --git a/tmux.h b/tmux.h
index 93e178e1..02f9bbd0 100644
--- a/tmux.h
+++ b/tmux.h
@@ -195,9 +195,15 @@ enum tty_code_code {
 	TTYC_CNORM,	/* cursor_normal, ve */
 	TTYC_COLORS,	/* max_colors, Co */
 	TTYC_CSR,	/* change_scroll_region, cs */
+	TTYC_CUB,	/* parm_left_cursor, LE */
+	TTYC_CUB1,	/* cursor_left, le */
 	TTYC_CUD,	/* parm_down_cursor, DO */
 	TTYC_CUD1,	/* cursor_down, do */
+	TTYC_CUF,	/* parm_right_cursor, RI */
+	TTYC_CUF1,	/* cursor_right, nd */
 	TTYC_CUP,	/* cursor_address, cm */
+	TTYC_CUU,	/* parm_up_cursor, UP */
+	TTYC_CUU1,	/* cursor_up, up */
 	TTYC_DCH,	/* parm_dch, DC */
 	TTYC_DCH1,	/* delete_character, dc */
 	TTYC_DIM,	/* enter_dim_mode, mh */
@@ -206,6 +212,8 @@ enum tty_code_code {
 	TTYC_EL,	/* clr_eol, ce */
 	TTYC_EL1,	/* clr_bol, cb */
 	TTYC_ENACS,	/* ena_acs, eA */
+	TTYC_HOME,	/* cursor_home, ho */
+	TTYC_HPA,	/* column_address, ch */
 	TTYC_ICH,	/* parm_ich, IC */
 	TTYC_ICH1,	/* insert_character, ic */
 	TTYC_IL,	/* parm_insert_line, IL */
@@ -232,8 +240,8 @@ enum tty_code_code {
 	TTYC_KF17,	/* key_f17, F7 */
 	TTYC_KF18,	/* key_f18, F8 */
 	TTYC_KF19,	/* key_f19, F9 */
-	TTYC_KF20,	/* key_f20, F10 */
 	TTYC_KF2,	/* key_f2, k2 */
+	TTYC_KF20,	/* key_f20, F10 */
 	TTYC_KF3,	/* key_f3, k3 */
 	TTYC_KF4,	/* key_f4, k4 */
 	TTYC_KF5,	/* key_f5, k5 */
@@ -262,6 +270,7 @@ enum tty_code_code {
 	TTYC_SMKX,	/* keypad_xmit, ks */
 	TTYC_SMSO,	/* enter_standout_mode, so */
 	TTYC_SMUL,	/* enter_underline_mode, us */
+	TTYC_VPA,	/* row_address, cv */
 	TTYC_XENL,	/* eat_newline_glitch, xn */
 };
 #define NTTYCODE (TTYC_XENL + 1)
diff --git a/tty-term.c b/tty-term.c
index dd3e8e00..02dece6e 100644
--- a/tty-term.c
+++ b/tty-term.c
@@ -43,9 +43,15 @@ struct tty_term_code_entry tty_term_codes[NTTYCODE] = {
 	{ TTYC_CNORM, TTYCODE_STRING, "cnorm" },
 	{ TTYC_COLORS, TTYCODE_NUMBER, "colors" },
 	{ TTYC_CSR, TTYCODE_STRING, "csr" },
+	{ TTYC_CUB, TTYCODE_STRING, "cub" },
+	{ TTYC_CUB1, TTYCODE_STRING, "cub1" },
 	{ TTYC_CUD, TTYCODE_STRING, "cud" },
 	{ TTYC_CUD1, TTYCODE_STRING, "cud1" },
+	{ TTYC_CUF, TTYCODE_STRING, "cuf" },
+	{ TTYC_CUF1, TTYCODE_STRING, "cuf1" },
 	{ TTYC_CUP, TTYCODE_STRING, "cup" },
+	{ TTYC_CUU, TTYCODE_STRING, "cuu" },
+	{ TTYC_CUU1, TTYCODE_STRING, "cuu1" },
 	{ TTYC_DCH, TTYCODE_STRING, "dch" },
 	{ TTYC_DCH1, TTYCODE_STRING, "dch1" },
 	{ TTYC_DIM, TTYCODE_STRING, "dim" },
@@ -54,6 +60,8 @@ struct tty_term_code_entry tty_term_codes[NTTYCODE] = {
 	{ TTYC_EL, TTYCODE_STRING, "el" },
 	{ TTYC_EL1, TTYCODE_STRING, "el1" },
 	{ TTYC_ENACS, TTYCODE_STRING, "enacs" },
+	{ TTYC_HOME, TTYCODE_STRING, "home" },
+	{ TTYC_HPA, TTYCODE_STRING, "hpa" },
 	{ TTYC_ICH, TTYCODE_STRING, "ich" },
 	{ TTYC_ICH1, TTYCODE_STRING, "ich1" },
 	{ TTYC_IL, TTYCODE_STRING, "il" },
@@ -80,8 +88,8 @@ struct tty_term_code_entry tty_term_codes[NTTYCODE] = {
 	{ TTYC_KF17, TTYCODE_STRING, "kf17" },
 	{ TTYC_KF18, TTYCODE_STRING, "kf18" },
 	{ TTYC_KF19, TTYCODE_STRING, "kf19" },
-	{ TTYC_KF20, TTYCODE_STRING, "kf20" },
 	{ TTYC_KF2, TTYCODE_STRING, "kf2" },
+	{ TTYC_KF20, TTYCODE_STRING, "kf20" },
 	{ TTYC_KF3, TTYCODE_STRING, "kf3" },
 	{ TTYC_KF4, TTYCODE_STRING, "kf4" },
 	{ TTYC_KF5, TTYCODE_STRING, "kf5" },
@@ -110,6 +118,7 @@ struct tty_term_code_entry tty_term_codes[NTTYCODE] = {
 	{ TTYC_SMKX, TTYCODE_STRING, "smkx" },
 	{ TTYC_SMSO, TTYCODE_STRING, "smso" },
 	{ TTYC_SMUL, TTYCODE_STRING, "smul" },
+	{ TTYC_VPA, TTYCODE_STRING, "vpa" },
 	{ TTYC_XENL, TTYCODE_FLAG, "xenl" },
 };
 
diff --git a/tty.c b/tty.c
index f7ef8c0d..4172e38c 100644
--- a/tty.c
+++ b/tty.c
@@ -21,6 +21,7 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <stdlib.h>
 #include <string.h>
 #include <termios.h>
 #include <unistd.h>
@@ -916,13 +917,14 @@ tty_region(struct tty *tty, u_int rupper, u_int rlower)
 
 	tty->rupper = rupper;
 	tty->rlower = rlower;
-	
+
 	tty->cx = 0;
 	tty->cy = 0;
 
 	tty_putcode2(tty, TTYC_CSR, tty->rupper, tty->rlower);
 }
 
+/* Move cursor inside pane. */
 void
 tty_cursor_pane(struct tty *tty, const struct tty_ctx *ctx, u_int cx, u_int cy)
 {
@@ -931,17 +933,122 @@ tty_cursor_pane(struct tty *tty, const struct tty_ctx *ctx, u_int cx, u_int cy)
 	tty_cursor(tty, wp->xoff + cx, wp->yoff + cy);
 }
 
+/* Move cursor to absolute position. */
 void
 tty_cursor(struct tty *tty, u_int cx, u_int cy)
 {
-	if (cx == 0 && tty->cx != 0 && tty->cy == cy) {
-		tty->cx = 0;
+	struct tty_term	*term = tty->term;
+	u_int		 thisx, thisy;
+	int		 change;
+	
+	if (cx > tty->sx - 1)
+		cx = tty->sx - 1;
+
+	thisx = tty->cx;
+	if (thisx > tty->sx - 1)
+		thisx = tty->sx - 1;
+	thisy = tty->cy;
+
+	/* No change. */
+	if (cx == thisx && cy == thisy)
+		return;
+
+	/* Move to home position (0, 0). */
+	if (cx == 0 && cy == 0 && tty_term_has(term, TTYC_HOME)) {
+		tty_putcode(tty, TTYC_HOME);
+		goto out;
+	}
+
+	/* Zero on the next line. */
+	if (cx == 0 && cy == thisy + 1) {
 		tty_putc(tty, '\r');
-	} else if (tty->cx != cx || tty->cy != cy) {
-		tty->cx = cx;
-		tty->cy = cy;
-		tty_putcode2(tty, TTYC_CUP, tty->cy, tty->cx);
+		tty_putc(tty, '\n');
+		goto out;
+	}
+
+	/* Row staying the same. */
+	if (cy == thisy) {
+		/* To left edge. */
+		if (cx == 0)	{
+			tty_putc(tty, '\r');
+			goto out;
+		}
+
+		/* One to the left. */
+		if (cx == thisx - 1 && tty_term_has(term, TTYC_CUB1)) {
+			tty_putcode(tty, TTYC_CUB1);
+			goto out;
+		}
+
+		/* One to the right. */
+		if (cx == thisx + 1 && tty_term_has(term, TTYC_CUF1)) {
+			tty_putcode(tty, TTYC_CUF1);
+			goto out;
+		}
+
+		/* Calculate difference. */
+		change = thisx - cx;	/* +ve left, -ve right */
+
+		/*
+		 * Use HPA if change is larger than absolute, otherwise move
+		 * the cursor with CUB/CUF.
+		 */
+		if (abs(change) > cx && tty_term_has(term, TTYC_HPA)) {
+			tty_putcode1(tty, TTYC_HPA, cx);
+			goto out;
+		} else if (change > 0 && tty_term_has(term, TTYC_CUB)) {
+			tty_putcode1(tty, TTYC_CUB, change);
+			goto out;
+		} else if (change < 0 && tty_term_has(term, TTYC_CUF)) {
+			tty_putcode1(tty, TTYC_CUF, -change);
+			goto out;
+		}
+	}
+
+	/* Column staying the same. */
+	if (cx == thisx ) {
+		/* One above. */
+		if (cy != tty->rupper && 
+		    cy == thisy - 1 && tty_term_has(term, TTYC_CUU1)) {
+			tty_putcode(tty, TTYC_CUU1);
+			goto out;
+		}
+
+		/* One below. */
+		if (cy != tty->rlower &&
+		    cy == thisy + 1 && tty_term_has(term, TTYC_CUD1)) {
+			tty_putcode(tty, TTYC_CUD1);
+			goto out;
+		}
+
+		/* Calculate difference. */
+		change = thisy - cy;	/* +ve up, -ve down */
+
+		/*
+		 * Use VPA if change is larger than absolute or if this change
+		 * would cross the scroll region, otherwise use CUU/CUD.
+		 */
+		if ((abs(change) > cy ||
+		    (change < 0 && cy - change > tty->rlower) ||
+		    (change > 0 && cy - change < tty->rupper)) &&
+		    tty_term_has(term, TTYC_VPA)) {
+			tty_putcode1(tty, TTYC_VPA, cy);
+			goto out;
+		} else if (change > 0 && tty_term_has(term, TTYC_CUU)) {
+			tty_putcode1(tty, TTYC_CUU, change);
+			goto out;
+		} else if (change < 0 && tty_term_has(term, TTYC_CUD)) {
+			tty_putcode1(tty, TTYC_CUD, -change);
+			goto out;
+		}
 	}
+
+	/* Absolute movement. */
+	tty_putcode2(tty, TTYC_CUP, cy, cx);
+
+out:
+	tty->cx = cx;
+	tty->cy = cy;
 }
 
 void