(window_scroll_pixel_based): Exit the move_it_by_lines

loop whenever it stops making progress.

diff --git a/src/window.c b/src/window.c
index 2ea7cd1d6ddd2046393f8c20525b9be91f815aa4..3535e50673eea1456f5bd88af4f745f1b8a26c3d 100644 (file)
--- a/src/window.c
+++ b/src/window.c
@@ -4154,7 +4154,12 @@ window_scroll_pixel_based (window, n, whole, noerror)
             in the scroll margin at the top.  */
          move_it_to (&it, PT, -1, -1, -1, MOVE_TO_POS);
          while (it.current_y < this_scroll_margin)
-           move_it_by_lines (&it, 1, 1);
+           {
+             int prev = it.current_y;
+             move_it_by_lines (&it, 1, 1);
+             if (prev == it.current_y)
+               break;
+           }
          SET_PT_BOTH (IT_CHARPOS (it), IT_BYTEPOS (it));
        }
       else if (n < 0)