(Frecenter): If ARG < 0, and on a window system

frame, count in some empty lines when we can't move -ARG lines
down.

1 files changed, 11 insertions, 3 deletions

diff --git a/src/window.c b/src/window.c
index 5abff76c434..abd2e6230ab 100644
--- a/src/window.c
+++ b/src/window.c
@@ -4586,18 +4586,26 @@ and redisplay normally--don't erase and redraw the frame.")
         {
           struct it it;
           struct text_pos pt;
-          int y0, y1, h;
+          int y0, y1, h, nlines;
           
           SET_TEXT_POS (pt, PT, PT_BYTE);
           start_display (&it, w, pt);
           y0 = it.current_y;
 
-          /* The amount of pixels we have to move hack is the window
+          /* The amount of pixels we have to move back is the window
              height minus what's displayed in the line containing PT,
              and the lines below.  */
-          move_it_by_lines (&it, - XINT (arg) - 1, 1);
+          nlines = - XINT (arg) - 1;
+          move_it_by_lines (&it, nlines, 1);
+
           y1 = it.current_y - y0;
           h = line_bottom_y (&it) - y1;
+
+          /* If we can't move down NLINES lines because we hit
+             the end of the buffer, count in some empty lines.  */
+          if (it.vpos < nlines)
+            y1 += (nlines - it.vpos) * CANON_Y_UNIT (it.f);
+          
           y0 = it.last_visible_y - y1 - h;
           
           start_display (&it, w, pt);