(redisplay_window): Handle scroll_step along with

scroll_conservatively.  Fix 1-off error checking the limit for them.

diff --git a/src/xdisp.c b/src/xdisp.c
index 8b2eabb5e2fd3ebfc2f565a1dca7c108bda444a6..9564cd841f338151731e7f6cd7201a7e73f43afb 100644 (file)
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -2115,7 +2115,7 @@ redisplay_window (window, just_this_one, preserve_echo_area)
          goto done;
        }
       /* Don't bother trying redisplay with same start;
-       we already know it will lose */
+        we already know it will lose.  */
     }
   /* If current starting point was originally the beginning of a line
      but no longer is, find a new starting point.  */
@@ -2204,11 +2204,15 @@ redisplay_window (window, just_this_one, preserve_echo_area)
 
   /* Try to scroll by specified few lines */
 
-  if (scroll_conservatively && !current_buffer->clip_changed
+  if ((scroll_conservatively || scroll_step)
+      && !current_buffer->clip_changed
       && startp >= BEGV && startp <= ZV)
     {
       int this_scroll_margin = scroll_margin;
       int scroll_margin_pos, scroll_margin_bytepos;
+      int scroll_max = scroll_step;
+      if (scroll_conservatively)
+       scroll_max = scroll_conservatively;
 
       /* Don't use a scroll margin that is negative or too large.  */
       if (this_scroll_margin < 0)
@@ -2236,10 +2240,12 @@ redisplay_window (window, just_this_one, preserve_echo_area)
                                 pos_tab_offset (w, scroll_margin_pos,
                                                 scroll_margin_bytepos),
                                 w);
-         if (pos.vpos > scroll_conservatively)
+         if (pos.vpos >= scroll_max)
            goto scroll_fail_1;
 
-         pos = *vmotion (startp, pos.vpos + 1, w);
+         pos = *vmotion (startp,
+                         scroll_conservatively ? pos.vpos + 1 : scroll_step,
+                         w);
 
          if (! NILP (Vwindow_scroll_functions))
            {
@@ -2275,10 +2281,12 @@ redisplay_window (window, just_this_one, preserve_echo_area)
                                 XFASTINT (w->width), XFASTINT (w->hscroll),
                                 pos_tab_offset (w, PT, PT_BYTE),
                                 w);
-         if (pos.vpos > scroll_conservatively)
+         if (pos.vpos > scroll_max)
            goto scroll_fail_1;
 
-         pos = *vmotion (startp, -pos.vpos, w);
+         pos = *vmotion (startp,
+                         scroll_conservatively ? -pos.vpos : - scroll_step,
+                         w);
 
          if (! NILP (Vwindow_scroll_functions))
            {
@@ -2302,17 +2310,21 @@ redisplay_window (window, just_this_one, preserve_echo_area)
     scroll_fail_1: ;
     }
 
-  if (scroll_step && !current_buffer->clip_changed
+#if 0
+  if (scroll_step && ! scroll_margin && !current_buffer->clip_changed
       && startp >= BEGV && startp <= ZV)
     {
-      if (PT > startp)
+      if (margin_call == 0)
+       margin_call = (PT > startp ? 1 : -1);
+      if (margin_call > 0)
        {
          pos = *vmotion (Z - XFASTINT (w->window_end_pos), scroll_step, w);
          if (pos.vpos >= height)
            goto scroll_fail;
        }
 
-      pos = *vmotion (startp, (PT < startp ? - scroll_step : scroll_step), w);
+      pos = *vmotion (startp, (margin_call < 0 ? - scroll_step : scroll_step),
+                     w);
 
       if (PT >= pos.bufpos)
        {
@@ -2337,6 +2349,7 @@ redisplay_window (window, just_this_one, preserve_echo_area)
        }
     scroll_fail: ;
     }
+#endif
 
   /* Finally, just choose place to start which centers point */