Remember the number of lines scrolled into the history (versus cleared

into the history) and when resizing only use scrolled lines and not
cleared lines (which are probably not intended to reappear). From
Chaoren Lin.

1 files changed, 12 insertions, 1 deletions

diff --git a/usr.bin/tmux/grid.c b/usr.bin/tmux/grid.c
index 9fce513f98c..364eaba687b 100644
--- a/usr.bin/tmux/grid.c
+++ b/usr.bin/tmux/grid.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: grid.c,v 1.54 2016/07/15 00:49:08 nicm Exp $ */
+/* $OpenBSD: grid.c,v 1.55 2016/09/02 20:57:20 nicm Exp $ */
 
 /*
  * Copyright (c) 2008 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -99,6 +99,7 @@ grid_create(u_int sx, u_int sy, u_int hlimit)
 
 	gd->flags = GRID_HISTORY;
 
+	gd->hscrolled = 0;
 	gd->hsize = 0;
 	gd->hlimit = hlimit;
 
@@ -170,6 +171,8 @@ grid_collect_history(struct grid *gd)
 
 	grid_move_lines(gd, 0, yy, gd->hsize + gd->sy - yy);
 	gd->hsize -= yy;
+	if (gd->hscrolled > gd->hsize)
+		gd->hscrolled = gd->hsize;
 }
 
 /*
@@ -186,6 +189,7 @@ grid_scroll_history(struct grid *gd)
 	    sizeof *gd->linedata);
 	memset(&gd->linedata[yy], 0, sizeof gd->linedata[yy]);
 
+	gd->hscrolled++;
 	gd->hsize++;
 }
 
@@ -196,7 +200,9 @@ grid_clear_history(struct grid *gd)
 	grid_clear_lines(gd, 0, gd->hsize);
 	grid_move_lines(gd, 0, gd->hsize, gd->sy);
 
+	gd->hscrolled = 0;
 	gd->hsize = 0;
+
 	gd->linedata = xreallocarray(gd->linedata, gd->sy,
 	    sizeof *gd->linedata);
 }
@@ -231,6 +237,7 @@ grid_scroll_history_region(struct grid *gd, u_int upper, u_int lower)
 	memset(gl_lower, 0, sizeof *gl_lower);
 
 	/* Move the history offset down over the line. */
+	gd->hscrolled++;
 	gd->hsize++;
 }
 
@@ -914,6 +921,10 @@ grid_reflow(struct grid *dst, struct grid *src, u_int new_x)
 			grid_reflow_join(dst, &py, src_gl, new_x);
 		}
 		previous_wrapped = (src_gl->flags & GRID_LINE_WRAPPED);
+
+		/* This is where we started scrolling. */
+		if (line == sy + src->hsize - src->hscrolled - 1)
+			dst->hscrolled = 0;
 	}
 
 	grid_destroy(src);