From 86c93c6e34cfe927e8d4e2901febf2ee063fa88b Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicm@openbsd.org>
Date: Thu, 9 Jul 2009 07:58:14 +0000
Subject: [PATCH] Change inserting and deleting lines inside the scroll region
 to properly clear lines that should be inserted/deleted but not moved. Fixes
 problems with mutt reported by Brian Lewis, thanks.

---
 grid-view.c    | 14 +++++++++++---
 screen-write.c | 38 +++++++++++++++++++++++++++++++++-----
 2 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/grid-view.c b/grid-view.c
index a9144a1f..5ad8fc2f 100644
--- a/grid-view.c
+++ b/grid-view.c
@@ -134,13 +134,17 @@ grid_view_insert_lines(struct grid *gd, u_int py, u_int ny)
 void
 grid_view_insert_lines_region(struct grid *gd, u_int rlower, u_int py, u_int ny)
 {
+	u_int	ny2;
+
 	GRID_DEBUG(gd, "rlower=%u, py=%u, ny=%u", rlower, py, ny);
 
 	rlower = grid_view_y(gd, rlower);
 
 	py = grid_view_y(gd, py);
 
-	grid_move_lines(gd, py + ny, py, (rlower + 1) - py - ny);
+	ny2 = rlower + 1 - py - ny;
+	grid_move_lines(gd, rlower + 1 - ny2, py, ny2);
+ 	grid_clear(gd, 0, py + ny2, gd->sx, ny - ny2);
 }
 
 /* Delete lines. */
@@ -156,20 +160,24 @@ grid_view_delete_lines(struct grid *gd, u_int py, u_int ny)
 	sy = grid_view_y(gd, gd->sy);
 
 	grid_move_lines(gd, py, py + ny, sy - py - ny);
-	grid_clear(gd, 0, sy - ny, gd->sx, py + ny - (sy - ny));
+ 	grid_clear(gd, 0, sy - ny, gd->sx, py + ny - (sy - ny));
 }
 
 /* Delete lines inside scroll region. */
 void
 grid_view_delete_lines_region(struct grid *gd, u_int rlower, u_int py, u_int ny)
 {
+	u_int	ny2;
+
 	GRID_DEBUG(gd, "rlower=%u, py=%u, ny=%u", rlower, py, ny);
 
 	rlower = grid_view_y(gd, rlower);
 
 	py = grid_view_y(gd, py);
 
-	grid_move_lines(gd, py, py + ny, (rlower + 1) - py - ny);
+	ny2 = rlower + 1 - py - ny;
+	grid_move_lines(gd, py, py + ny, ny2);
+ 	grid_clear(gd, 0, py + ny2, gd->sx, ny - ny2);
 }
 
 /* Insert characters. */
diff --git a/screen-write.c b/screen-write.c
index 00a56c46..fb0cba6a 100644
--- a/screen-write.c
+++ b/screen-write.c
@@ -369,11 +369,25 @@ screen_write_insertline(struct screen_write_ctx *ctx, u_int ny)
 	if (ny == 0)
 		ny = 1;
 
-	if (ny > screen_size_y(s) - s->cy)
-		ny = screen_size_y(s) - s->cy;
+	if (s->cy < s->rupper || s->cy > s->rlower) {
+		if (ny > screen_size_y(s) - s->cy)
+			ny = screen_size_y(s) - s->cy;
+		if (ny == 0)
+			return;
+
+		screen_write_save(ctx);
+
+		grid_view_insert_lines(s->grid, s->cy, ny);
+
+		tty_write_cmd(ctx->wp, TTY_INSERTLINE, ny);
+		return;
+	}
+
+	if (ny > s->rlower + 1 - s->cy)
+		ny = s->rlower + 1 - s->cy;
 	if (ny == 0)
 		return;
-
+	
 	screen_write_save(ctx);
 
 	if (s->cy < s->rupper || s->cy > s->rlower)
@@ -393,8 +407,22 @@ screen_write_deleteline(struct screen_write_ctx *ctx, u_int ny)
 	if (ny == 0)
 		ny = 1;
 
-	if (ny > screen_size_y(s) - s->cy)
-		ny = screen_size_y(s) - s->cy;
+	if (s->cy < s->rupper || s->cy > s->rlower) {
+		if (ny > screen_size_y(s) - s->cy)
+			ny = screen_size_y(s) - s->cy;
+		if (ny == 0)
+			return;
+
+		screen_write_save(ctx);
+
+		grid_view_delete_lines(s->grid, s->cy, ny);
+
+		tty_write_cmd(ctx->wp, TTY_DELETELINE, ny);
+		return;
+	}
+	
+	if (ny > s->rlower + 1 - s->cy)
+		ny = s->rlower + 1 - s->cy;
 	if (ny == 0)
 		return;