Add support for the SD (scroll down) escape sequence, GitHub issue 1861.

5 files changed, 76 insertions, 4 deletions

diff --git a/input.c b/input.c
index ff8d7a17..f37f8fd8 100644
--- a/input.c
+++ b/input.c
@@ -244,6 +244,7 @@ enum input_csi_type {
 	INPUT_CSI_RM,
 	INPUT_CSI_RM_PRIVATE,
 	INPUT_CSI_SCP,
+	INPUT_CSI_SD,
 	INPUT_CSI_SGR,
 	INPUT_CSI_SM,
 	INPUT_CSI_SM_PRIVATE,
@@ -270,6 +271,7 @@ static const struct input_table_entry input_csi_table[] = {
 	{ 'M', "",  INPUT_CSI_DL },
 	{ 'P', "",  INPUT_CSI_DCH },
 	{ 'S', "",  INPUT_CSI_SU },
+	{ 'T', "",  INPUT_CSI_SD },
 	{ 'X', "",  INPUT_CSI_ECH },
 	{ 'Z', "",  INPUT_CSI_CBT },
 	{ '`', "",  INPUT_CSI_HPA },
@@ -1525,6 +1527,11 @@ input_csi_dispatch(struct input_ctx *ictx)
 		if (n != -1)
 			screen_write_scrollup(sctx, n, bg);
 		break;
+	case INPUT_CSI_SD:
+		n = input_get(ictx, 0, 1, 1);
+		if (n != -1)
+			screen_write_scrolldown(sctx, n, bg);
+		break;
 	case INPUT_CSI_TBC:
 		switch (input_get(ictx, 0, 0, 0)) {
 		case -1:
diff --git a/screen-write.c b/screen-write.c
index 98cdf158..66053eaf 100644
--- a/screen-write.c
+++ b/screen-write.c
@@ -1088,6 +1088,31 @@ screen_write_scrollup(struct screen_write_ctx *ctx, u_int lines, u_int bg)
 	ctx->scrolled += lines;
 }
 
+/* Scroll down. */
+void
+screen_write_scrolldown(struct screen_write_ctx *ctx, u_int lines, u_int bg)
+{
+	struct screen	*s = ctx->s;
+	struct grid	*gd = s->grid;
+	struct tty_ctx	 ttyctx;
+	u_int		 i;
+
+	screen_write_initctx(ctx, &ttyctx);
+	ttyctx.bg = bg;
+
+	if (lines == 0)
+		lines = 1;
+	else if (lines > s->rlower - s->rupper + 1)
+		lines = s->rlower - s->rupper + 1;
+
+	for (i = 0; i < lines; i++)
+		grid_view_scroll_region_down(gd, s->rupper, s->rlower, bg);
+
+	screen_write_collect_flush(ctx, 0);
+	ttyctx.num = lines;
+	tty_write(tty_cmd_scrolldown, &ttyctx);
+}
+
 /* Carriage return (cursor to start of line). */
 void
 screen_write_carriagereturn(struct screen_write_ctx *ctx)
diff --git a/tmux.h b/tmux.h
index 5c10420a..9bf9f933 100644
--- a/tmux.h
+++ b/tmux.h
@@ -422,6 +422,7 @@ enum tty_code_code {
 	TTYC_REV,
 	TTYC_RGB,
 	TTYC_RI,
+	TTYC_RIN,
 	TTYC_RMACS,
 	TTYC_RMCUP,
 	TTYC_RMKX,
@@ -1927,6 +1928,7 @@ void	tty_cmd_insertcharacter(struct tty *, const struct tty_ctx *);
 void	tty_cmd_insertline(struct tty *, const struct tty_ctx *);
 void	tty_cmd_linefeed(struct tty *, const struct tty_ctx *);
 void	tty_cmd_scrollup(struct tty *, const struct tty_ctx *);
+void	tty_cmd_scrolldown(struct tty *, const struct tty_ctx *);
 void	tty_cmd_reverseindex(struct tty *, const struct tty_ctx *);
 void	tty_cmd_setselection(struct tty *, const struct tty_ctx *);
 void	tty_cmd_rawstring(struct tty *, const struct tty_ctx *);
@@ -2303,6 +2305,7 @@ void	 screen_write_reverseindex(struct screen_write_ctx *, u_int);
 void	 screen_write_scrollregion(struct screen_write_ctx *, u_int, u_int);
 void	 screen_write_linefeed(struct screen_write_ctx *, int, u_int);
 void	 screen_write_scrollup(struct screen_write_ctx *, u_int, u_int);
+void	 screen_write_scrolldown(struct screen_write_ctx *, u_int, u_int);
 void	 screen_write_carriagereturn(struct screen_write_ctx *);
 void	 screen_write_clearendofscreen(struct screen_write_ctx *, u_int);
 void	 screen_write_clearstartofscreen(struct screen_write_ctx *, u_int);
diff --git a/tty-term.c b/tty-term.c
index eabadf6b..182edd7d 100644
--- a/tty-term.c
+++ b/tty-term.c
@@ -242,6 +242,7 @@ static const struct tty_term_code_entry tty_term_codes[] = {
 	[TTYC_REV] = { TTYCODE_STRING, "rev" },
 	[TTYC_RGB] = { TTYCODE_FLAG, "RGB" },
 	[TTYC_RI] = { TTYCODE_STRING, "ri" },
+	[TTYC_RIN] = { TTYCODE_STRING, "rin" },
 	[TTYC_RMACS] = { TTYCODE_STRING, "rmacs" },
 	[TTYC_RMCUP] = { TTYCODE_STRING, "rmcup" },
 	[TTYC_RMKX] = { TTYCODE_STRING, "rmkx" },
diff --git a/tty.c b/tty.c
index 024aef27..1658fb74 100644
--- a/tty.c
+++ b/tty.c
@@ -1558,10 +1558,11 @@ tty_cmd_reverseindex(struct tty *tty, const struct tty_ctx *ctx)
 		return;
 
 	if (ctx->bigger ||
-	    !tty_pane_full_width(tty, ctx) ||
+	    (!tty_pane_full_width(tty, ctx) && !tty_use_margin(tty)) ||
 	    tty_fake_bce(tty, wp, 8) ||
 	    !tty_term_has(tty->term, TTYC_CSR) ||
-	    !tty_term_has(tty->term, TTYC_RI) ||
+	    (!tty_term_has(tty->term, TTYC_RI) &&
+	    !tty_term_has(tty->term, TTYC_RIN)) ||
 	    ctx->wp->sx == 1 ||
 	    ctx->wp->sy == 1) {
 		tty_redraw_region(tty, ctx);
@@ -1571,10 +1572,13 @@ tty_cmd_reverseindex(struct tty *tty, const struct tty_ctx *ctx)
 	tty_default_attributes(tty, wp, ctx->bg);
 
 	tty_region_pane(tty, ctx, ctx->orupper, ctx->orlower);
-	tty_margin_off(tty);
+	tty_margin_pane(tty, ctx);
 	tty_cursor_pane(tty, ctx, ctx->ocx, ctx->orupper);
 
-	tty_putcode(tty, TTYC_RI);
+	if (tty_term_has(tty->term, TTYC_RI))
+		tty_putcode(tty, TTYC_RI);
+	else
+		tty_putcode1(tty, TTYC_RIN, 1);
 }
 
 void
@@ -1653,6 +1657,38 @@ tty_cmd_scrollup(struct tty *tty, const struct tty_ctx *ctx)
 }
 
 void
+tty_cmd_scrolldown(struct tty *tty, const struct tty_ctx *ctx)
+{
+	struct window_pane	*wp = ctx->wp;
+	u_int			 i;
+
+	if (ctx->bigger ||
+	    (!tty_pane_full_width(tty, ctx) && !tty_use_margin(tty)) ||
+	    tty_fake_bce(tty, wp, 8) ||
+	    !tty_term_has(tty->term, TTYC_CSR) ||
+	    (!tty_term_has(tty->term, TTYC_RI) &&
+	    !tty_term_has(tty->term, TTYC_RIN)) ||
+	    wp->sx == 1 ||
+	    wp->sy == 1) {
+		tty_redraw_region(tty, ctx);
+		return;
+	}
+
+	tty_default_attributes(tty, wp, ctx->bg);
+
+	tty_region_pane(tty, ctx, ctx->orupper, ctx->orlower);
+	tty_margin_pane(tty, ctx);
+	tty_cursor_pane(tty, ctx, ctx->ocx, ctx->orupper);
+
+	if (tty_term_has(tty->term, TTYC_RIN))
+		tty_putcode1(tty, TTYC_RIN, ctx->num);
+	else {
+		for (i = 0; i < ctx->num; i++)
+			tty_putcode(tty, TTYC_RI);
+	}
+}
+
+void
 tty_cmd_clearendofscreen(struct tty *tty, const struct tty_ctx *ctx)
 {
 	struct window_pane	*wp = ctx->wp;