Improve cursor positioning after reflow by storing the position as an

offset into the entire history before reflow and restoring it aftewards.

1 files changed, 27 insertions, 31 deletions

diff --git a/screen.c b/screen.c
index 75d9d09d..92eb31de 100644
--- a/screen.c
+++ b/screen.c
@@ -48,7 +48,6 @@ struct screen_title_entry {
 };
 TAILQ_HEAD(screen_titles, screen_title_entry);
 
-static void	screen_resize_x(struct screen *, u_int);
 static void	screen_resize_y(struct screen *, u_int);
 
 static void	screen_reflow(struct screen *, u_int);
@@ -207,13 +206,7 @@ screen_resize(struct screen *s, u_int sx, u_int sy, int reflow)
 		sy = 1;
 
 	if (sx != screen_size_x(s)) {
-		screen_resize_x(s, sx);
-
-		/*
-		 * It is unclear what should happen to tabs on resize. xterm
-		 * seems to try and maintain them, rxvt resets them. Resetting
-		 * is simpler and more reliable so let's do that.
-		 */
+		s->grid->sx = sx;
 		screen_reset_tabs(s);
 	} else
 		reflow = 0;
@@ -226,28 +219,6 @@ screen_resize(struct screen *s, u_int sx, u_int sy, int reflow)
 }
 
 static void
-screen_resize_x(struct screen *s, u_int sx)
-{
-	struct grid		*gd = s->grid;
-
-	if (sx == 0)
-		fatalx("zero size");
-
-	/*
-	 * Treat resizing horizontally simply: just ensure the cursor is
-	 * on-screen and change the size. Don't bother to truncate any lines -
-	 * then the data should be accessible if the size is then increased.
-	 *
-	 * The only potential wrinkle is if UTF-8 double-width characters are
-	 * left in the last column, but UTF-8 terminals should deal with this
-	 * sanely.
-	 */
-	if (s->cx >= sx)
-		s->cx = sx - 1;
-	gd->sx = sx;
-}
-
-static void
 screen_resize_y(struct screen *s, u_int sy)
 {
 	struct grid	*gd = s->grid;
@@ -493,5 +464,30 @@ screen_select_cell(struct screen *s, struct grid_cell *dst,
 static void
 screen_reflow(struct screen *s, u_int new_x)
 {
-	grid_reflow(s->grid, new_x, &s->cy);
+	u_int		offset, cx = s->cx, cy = s->grid->hsize + s->cy;
+	struct timeval	start, tv;
+
+	gettimeofday(&start, NULL);
+
+	offset = grid_to_offset(s->grid, cx, cy);
+	log_debug("%s: cursor %u,%u offset is %u", __func__, cx, cy, offset);
+
+	grid_reflow(s->grid, new_x);
+
+	grid_from_offset(s->grid, offset, &cx, &cy);
+	log_debug("%s: new cursor is %u,%u", __func__, cx, cy);
+
+	if (cy >= s->grid->hsize) {
+		s->cx = cx;
+		s->cy = cy - s->grid->hsize;
+	} else {
+		s->cx = 0;
+		s->cy = 0;
+	}
+
+	gettimeofday(&tv, NULL);
+	timersub(&tv, &start, &tv);
+
+	log_debug("%s: reflow took %llu.%06u seconds", __func__,
+	    (unsigned long long)tv.tv_sec, (u_int)tv.tv_usec);
 }