Add support for scroll up escape sequence (CSI S) and use it when

possible instead of sending individual line feeds.

1 files changed, 26 insertions, 0 deletions

diff --git a/tty.c b/tty.c
index 508e4bac..40bd7a40 100644
--- a/tty.c
+++ b/tty.c
@@ -1022,6 +1022,32 @@ tty_cmd_linefeed(struct tty *tty, const struct tty_ctx *ctx)
 }
 
 void
+tty_cmd_scrollup(struct tty *tty, const struct tty_ctx *ctx)
+{
+	struct window_pane	*wp = ctx->wp;
+	u_int			 i;
+
+	if ((!tty_pane_full_width(tty, ctx) && !tty_use_margin(tty)) ||
+	    tty_fake_bce(tty, wp, ctx->bg) ||
+	    !tty_term_has(tty->term, TTYC_CSR)) {
+		tty_redraw_region(tty, ctx);
+		return;
+	}
+
+	tty_attributes(tty, &grid_default_cell, wp);
+
+	tty_region_pane(tty, ctx, ctx->orupper, ctx->orlower);
+	tty_margin_pane(tty, ctx);
+
+	if (ctx->num == 1 || !tty_term_has(tty->term, TTYC_INDN)) {
+		tty_cursor(tty, tty->rright, ctx->yoff + tty->rlower);
+		for (i = 0; i < ctx->num; i++)
+			tty_putc(tty, '\n');
+	} else
+		tty_putcode1(tty, TTYC_INDN, ctx->num);
+}
+
+void
 tty_cmd_clearendofscreen(struct tty *tty, const struct tty_ctx *ctx)
 {
 	struct window_pane	*wp = ctx->wp;