(try_window): New arg CHECK_MARGINS. Calls changed.

(redisplay_window): Handle try_window reporting point in scroll margin.

1 files changed, 49 insertions, 12 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index 5bb157cae73..51ce35fedd7 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -7592,7 +7592,7 @@ display_echo_area_1 (a1, a2, a3, a4)
   clear_glyph_matrix (w->desired_matrix);
   XSETWINDOW (window, w);
   SET_TEXT_POS (start, BEG, BEG_BYTE);
-  try_window (window, start);
+  try_window (window, start, 0);
 
   return window_height_changed_p;
 }
@@ -11570,7 +11570,7 @@ try_scrolling (window, just_this_one_p, scroll_conservatively,
 
   /* Display the window.  Give up if new fonts are loaded, or if point
      doesn't appear.  */
-  if (!try_window (window, startp))
+  if (!try_window (window, startp, 0))
     rc = SCROLLING_NEED_LARGER_MATRICES;
   else if (w->cursor.vpos < 0)
     {
@@ -12173,6 +12173,7 @@ redisplay_window (window, just_this_one_p)
     {
       /* We set this later on if we have to adjust point.  */
       int new_vpos = -1;
+      int val;
 
       w->force_start = Qnil;
       w->vscroll = 0;
@@ -12206,12 +12207,16 @@ redisplay_window (window, just_this_one_p)
 
       /* Redisplay, then check if cursor has been set during the
          redisplay.  Give up if new fonts were loaded.  */
-      if (!try_window (window, startp))
+      val = try_window (window, startp, 1);
+      if (!val)
         {
           w->force_start = Qt;
           clear_glyph_matrix (w->desired_matrix);
           goto need_larger_matrices;
         }
+      /* Point was outside the scroll margins.  */
+      if (val < 0)
+        new_vpos = window_box_height (w) / 2;
 
       if (w->cursor.vpos < 0 && !w->frozen_window_start_p)
         {
@@ -12254,7 +12259,7 @@ redisplay_window (window, just_this_one_p)
               && !NILP (current_buffer->mark_active))
             {
               clear_glyph_matrix (w->desired_matrix);
-              if (!try_window (window, startp))
+              if (!try_window (window, startp, 0))
                 goto need_larger_matrices;
             }
         }
@@ -12344,7 +12349,11 @@ redisplay_window (window, just_this_one_p)
                = try_window_reusing_current_matrix (w)))
         {
           IF_DEBUG (debug_method_add (w, "1"));
-          try_window (window, startp);
+          if (try_window (window, startp, 1) < 0)
+            /* -1 means we need to scroll.
+               0 means we need new matrices, but fonts_changed_p
+               is set in that case, so we will detect it below.  */
+            goto try_to_scroll;
         }
 
       if (fonts_changed_p)
@@ -12474,7 +12483,7 @@ redisplay_window (window, just_this_one_p)
       || MINI_WINDOW_P (w)
       || !(used_current_matrix_p
            = try_window_reusing_current_matrix (w)))
-    try_window (window, startp);
+    try_window (window, startp, 0);
 
   /* If new fonts have been loaded (due to fontsets), give up.  We
      have to start a new redisplay since we need to re-adjust glyph
@@ -12494,13 +12503,13 @@ redisplay_window (window, just_this_one_p)
         {
           clear_glyph_matrix (w->desired_matrix);
           move_it_by_lines (&it, 1, 0);
-          try_window (window, it.current.pos);
+          try_window (window, it.current.pos, 0);
         }
       else if (PT < IT_CHARPOS (it))
         {
           clear_glyph_matrix (w->desired_matrix);
           move_it_by_lines (&it, -1, 0);
-          try_window (window, it.current.pos);
+          try_window (window, it.current.pos, 0);
         }
       else
         {
@@ -12683,14 +12692,18 @@ redisplay_window (window, just_this_one_p)
 
 
 /* Build the complete desired matrix of WINDOW with a window start
-   buffer position POS.  Value is non-zero if successful.  It is zero
-   if fonts were loaded during redisplay which makes re-adjusting
-   glyph matrices necessary.  */
+   buffer position POS.
+
+   Value is 1 if successful.  It is zero if fonts were loaded during
+   redisplay which makes re-adjusting glyph matrices necessary, and -1
+   if point would appear in the scroll margins.
+   (We check that only if CHECK_MARGINS is nonzero.  */
 
 int
-try_window (window, pos)
+try_window (window, pos, check_margins)
      Lisp_Object window;
      struct text_pos pos;
+     int check_margins;
 {
   struct window *w = XWINDOW (window);
   struct it it;
@@ -12715,6 +12728,30 @@ try_window (window, pos)
         return 0;
     }
 
+  /* Don't let the cursor end in the scroll margins.  */
+  if (check_margins)
+    {
+      int this_scroll_margin, cursor_height;
+
+      this_scroll_margin = max (0, scroll_margin);
+      this_scroll_margin = min (this_scroll_margin, WINDOW_TOTAL_LINES (w) / 4);
+      this_scroll_margin *= FRAME_LINE_HEIGHT (it.f);
+      cursor_height = MATRIX_ROW (w->desired_matrix, w->cursor.vpos)->height;
+
+      if ((w->cursor.y < this_scroll_margin
+           && CHARPOS (pos) > BEGV)
+          /* Old redisplay didn't take scroll margin into account at the bottom,
+             but then global-hl-line-mode doesn't scroll.  KFS 2004-06-14 */
+          || (w->cursor.y + (make_cursor_line_fully_visible_p
+                             ? cursor_height + this_scroll_margin
+                             : 1)) > it.last_visible_y)
+        {
+          w->cursor.vpos = -1;
+          clear_glyph_matrix (w->desired_matrix);
+          return -1;
+        }
+    }
+
   /* If bottom moved off end of frame, change mode line percentage.  */
   if (XFASTINT (w->window_end_pos) <= 0
       && Z != IT_CHARPOS (it))