From 45f4ff54850ff9b448070a96b33e63451f973e33 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Mon, 5 Aug 2019 06:42:02 +0000
Subject: Add support for the SD (scroll down) escape sequence, GitHub issue
 1861.

---
 screen-write.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

(limited to 'screen-write.c')

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)
-- 
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