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

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

diff --git a/src/window.c b/src/window.c
index 5abff76..abd2e62 100644 (file)
--- 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);