(redisplay_window) <force-start case>:

If point is on semi-visible last line, reposition
it at previous line.

diff --git a/src/xdisp.c b/src/xdisp.c
index f277abee47f794a9e26d7446d8d1f1d9bb99af2d..b6fe751237fe60bb7c952fabca975c5d0a47a68a 100644 (file)
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -8963,6 +8963,8 @@ redisplay_internal (preserve_echo_area)
                judge_scroll_bars_hook (f);
 
              /* If fonts changed, display again.  */
+             /* ??? rms: I suspect it is a mistake to jump all the way
+                back to retry here.  It should just retry this frame.  */
              if (fonts_changed_p)
                goto retry;
 
@@ -10098,7 +10100,11 @@ try_cursor_movement (window, startp, scroll_step)
 
 
 /* Redisplay leaf window WINDOW.  JUST_THIS_ONE_P non-zero means only
-   selected_window is redisplayed.  */
+   selected_window is redisplayed.
+
+   We can return without actually redisplaying the window if
+   fonts_changed_p is nonzero.  In that case, redisplay_internal will
+   retry.  */
 
 static void
 redisplay_window (window, just_this_one_p)
@@ -10305,6 +10311,9 @@ redisplay_window (window, just_this_one_p)
   if (!NILP (w->force_start)
       || w->frozen_window_start_p)
     {
+      /* We set this later on if we have to adjust point.  */
+      int new_vpos = -1;
+
       w->force_start = Qnil;
       w->vscroll = 0;
       w->window_end_valid = Qnil;
@@ -10341,7 +10350,7 @@ redisplay_window (window, just_this_one_p)
        {
          w->force_start = Qt;
          clear_glyph_matrix (w->desired_matrix);
-         goto finish_scroll_bars;
+         goto need_larger_matrices;
        }
 
       if (w->cursor.vpos < 0 && !w->frozen_window_start_p)
@@ -10349,12 +10358,24 @@ redisplay_window (window, just_this_one_p)
          /* If point does not appear, try to move point so it does
             appear. The desired matrix has been built above, so we
             can use it here.  */
-         int window_height;
+         new_vpos = window_box_height (w) / 2;
+       }
+
+      if (!make_cursor_line_fully_visible (w))
+       {
+         /* Point does appear, but on a line partly visible at end of window.
+            Move it back to a fully-visible line.  */
+         new_vpos = window_box_height (w);
+       }
+
+      /* If we need to move point for either of the above reasons,
+        now actually do it.  */
+      if (new_vpos >= 0)
+       {
          struct glyph_row *row;
 
-         window_height = window_box_height (w) / 2;
          row = MATRIX_FIRST_TEXT_ROW (w->desired_matrix);
-         while (MATRIX_ROW_BOTTOM_Y (row) < window_height)
+         while (MATRIX_ROW_BOTTOM_Y (row) < new_vpos)
            ++row;
 
          TEMP_SET_PT_BOTH (MATRIX_ROW_START_CHARPOS (row),
@@ -10378,45 +10399,6 @@ redisplay_window (window, just_this_one_p)
            }
        }
 
-      if (!make_cursor_line_fully_visible (w))
-       {
-         /* CVS rev. 1.761 had changed this to ``goto try_to_scroll''.
-
-            The intention of the fix -- AFAIU -- was to ensure that 
-            the cursor didn't end up on a partially visible last (or
-            first?) line when scrolling.
-
-
-            But that change causes havoc when scrolling backwards and
-            a partially visible first (or last?) line is present when
-            we reach the top of the buffer.  In effect, the text
-            already in the window is repeated (each line is appended
-            to the same or another lines in the window)...
-
-            I changed it back to ``goto need_larger_matrices'' which
-            in effect mean that we don't go through `try_scrolling'
-            when the cursor is already at the first line of the buffer,
-            and there is really only a few pixels [rather than lines]
-            to scroll backwards.  I guess move_it_by_lines etc. really
-            isn't the right device for doing that, ref. the code in
-            make_cursor_line_fully_visible which was also disabled by
-            CVS rev. 1.761.
-
-            But how do we know that we are already on the top line of
-            the window showing the first line in the buffer, so that
-            scrolling really wont help here?
-
-            I cannot find a simple fix for this (I tried various
-            approaches), but I prefer to an occasional partial line
-            rather than the visual messup, so I reverted this part of
-            the fix.
-
-            Someone will need to look into this when time allows.
-
-            -- 2002-08-22, Kim F. Storm  */
-
-         goto need_larger_matrices;
-       }
 #if GLYPH_DEBUG
       debug_method_add (w, "forced window start");
 #endif
@@ -10435,8 +10417,10 @@ redisplay_window (window, just_this_one_p)
        case CURSOR_MOVEMENT_SUCCESS:
          goto done;
 
+#if 0  /* try_cursor_movement never returns this value.  */
        case CURSOR_MOVEMENT_NEED_LARGER_MATRICES:
          goto need_larger_matrices;
+#endif
 
        case CURSOR_MOVEMENT_MUST_SCROLL:
          goto try_to_scroll;
@@ -10765,6 +10749,10 @@ redisplay_window (window, just_this_one_p)
 #endif
     }
 
+  /* We go to this label, with fonts_changed_p nonzero,
+     if it is necessary to try again using larger glyph matrices.
+     We have to redeem the scroll bar even in this case,
+     because the loop in redisplay_internal expects that.  */
  need_larger_matrices:
   ;
  finish_scroll_bars: