Implement a tool bar containing modifier keys

* doc/emacs/frames.texi (Tool Bars): Describe modifier bars.
* doc/lispref/keymaps.texi (Extended Menu Items, Tool Bar):
Document changes to tool bar menu item handling and secondary
tool bars.
* etc/NEWS: Announce changes.
* lisp/simple.el (event-apply-modifier): Correctly apply Ctrl
and Shift modifiers to lower case ASCII key events that already
have other modifiers applied.
* lisp/tool-bar.el (tool-bar--cache-key)
(tool-bar--secondary-cache-key): New defsubsts.
(tool-bar--flush-cache): Flush secondary tool bar cache.
(tool-bar-make-keymap): Include secondary tool bar if necessary.
(tool-bar-make-keymap-1): New arg MAP.  Generate a keymap for
that map if specified, else default to tool-bar-map.
(set-text-conversion-style, tool-bar-apply-modifiers)
(overriding-text-conversion-style)
(tool-bar-event-apply-alt-modifier)
(tool-bar-event-apply-super-modifier)
(tool-bar-event-apply-hyper-modifier)
(tool-bar-event-apply-shift-modifier)
(tool-bar-event-apply-control-modifier)
(tool-bar-event-apply-meta-modifier, modifier-bar-mode): New
functions.
* src/dispextern.h (enum tool_bar_item_idx): Add
TOOL_BAR_ITEM_WRAP.
* src/frame.c (make_frame): Clear new field `tool_bar_wraps_p'.
* src/frame.h (struct frame): New field `tool_bar_wraps_p'.
* src/keyboard.c (parse_tool_bar_item): Handle QCwrap properties
in tool bar menu items.
(syms_of_keyboard): New defsym QCwrap.
* src/xdisp.c (build_desired_tool_bar_string): Clear
f->tool_bar_wraps_p and set it appropriately.  Insert new line
characters in the tool bar string upon encountering a wrap
character.
(display_tool_bar_line): Stop at EOB, not line end.  Reseat on
the next line upon encountering EOL characters.
(redisplay_tool_bar): Allow rows to be different heights if
explicit new lines are present upon the tool bar string.

5 files changed, 134 insertions, 19 deletions

diff --git a/src/dispextern.h b/src/dispextern.h
index 402972d33d9..cf67121809f 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -3364,9 +3364,13 @@ enum tool_bar_item_idx
   /* If we shall show the label only below the icon and not beside it.  */
   TOOL_BAR_ITEM_VERT_ONLY,
 
+  /* Whether or not this tool bar item is hidden and should cause
+     subsequent items to be displayed on a new line.  */
+  TOOL_BAR_ITEM_WRAP,
+
   /* Sentinel = number of slots in tool_bar_items occupied by one
      tool-bar item.  */
-  TOOL_BAR_ITEM_NSLOTS
+  TOOL_BAR_ITEM_NSLOTS,
 };
 
 
diff --git a/src/frame.c b/src/frame.c
index 65711106671..35881ce6de1 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -986,6 +986,7 @@ make_frame (bool mini_p)
   f->last_tab_bar_item = -1;
 #ifndef HAVE_EXT_TOOL_BAR
   f->last_tool_bar_item = -1;
+  f->tool_bar_wraps_p = false;
 #endif
 #ifdef NS_IMPL_COCOA
   f->ns_appearance = ns_appearance_system_default;
diff --git a/src/frame.h b/src/frame.h
index 8142dec456b..8ed9c0f37d8 100644
--- a/src/frame.h
+++ b/src/frame.h
@@ -344,6 +344,10 @@ struct frame
   /* Set to true to minimize tool-bar height even when
      auto-resize-tool-bar is set to grow-only.  */
   bool_bf minimize_tool_bar_window_p : 1;
+
+  /* Whether or not the tool bar contains a ``new line'' item.  If
+     true, tool bar rows will be allowed to differ in height.  */
+  bool_bf tool_bar_wraps_p : 1;
 #endif
 
 #ifdef HAVE_EXT_TOOL_BAR
diff --git a/src/keyboard.c b/src/keyboard.c
index 19fdbd11724..b33fbf8f155 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -9325,7 +9325,13 @@ set_prop (ptrdiff_t idx, Lisp_Object val)
 
    - `:label LABEL-STRING'.
 
-   A text label to show with the tool bar button if labels are enabled.  */
+   A text label to show with the tool bar button if labels are
+   enabled.
+
+   - `:wrap WRAP'
+
+   WRAP specifies whether to hide this item but display subsequent
+   tool bar items on a new line.  */
 
 static bool
 parse_tool_bar_item (Lisp_Object key, Lisp_Object item)
@@ -9333,7 +9339,15 @@ parse_tool_bar_item (Lisp_Object key, Lisp_Object item)
   Lisp_Object filter = Qnil;
   Lisp_Object caption;
   int i;
-  bool have_label = false;
+  bool have_label;
+#ifndef HAVE_EXT_TOOL_BAR
+  bool is_wrap;
+#endif /* HAVE_EXT_TOOL_BAR */
+
+  have_label = false;
+#ifndef HAVE_EXT_TOOL_BAR
+  is_wrap = false;
+#endif /* HAVE_EXT_TOOL_BAR */
 
   /* Definition looks like `(menu-item CAPTION BINDING PROPS...)'.
      Rule out items that aren't lists, don't start with
@@ -9469,6 +9483,20 @@ parse_tool_bar_item (Lisp_Object key, Lisp_Object item)
       else if (EQ (ikey, QCrtl))
         /* ':rtl STRING' */
         set_prop (TOOL_BAR_ITEM_RTL_IMAGE, value);
+      else if (EQ (ikey, QCwrap))
+        {
+#ifndef HAVE_EXT_TOOL_BAR
+          /* This specifies whether the tool bar item should be hidden
+             but cause subsequent items to be displayed on a new
+             line.  */
+          set_prop (TOOL_BAR_ITEM_WRAP, value);
+          is_wrap = !NILP (value);
+#else /* HAVE_EXT_TOOL_BAR */
+          /* Line wrapping isn't supported on builds utilizing
+             external tool bars.  */
+          return false;
+#endif /* !HAVE_EXT_TOOL_BAR */
+        }
     }
 
 
@@ -9529,6 +9557,15 @@ parse_tool_bar_item (Lisp_Object key, Lisp_Object item)
   if (CONSP (get_keymap (PROP (TOOL_BAR_ITEM_BINDING), 0, 1)))
     return 0;
 
+
+#ifndef HAVE_EXT_TOOL_BAR
+  /* If the menu item is actually a line wrap, make sure it isn't
+     visible or enabled.  */
+
+  if (is_wrap)
+    set_prop (TOOL_BAR_ITEM_ENABLED_P, Qnil);
+#endif /* !HAVE_EXT_TOOL_BAR */
+
   /* If there is a key binding, add it to the help, which will be
      displayed as a tooltip for this entry. */
   Lisp_Object binding = PROP (TOOL_BAR_ITEM_BINDING);
@@ -12482,6 +12519,7 @@ syms_of_keyboard (void)
   DEFSYM (Qhelp_echo, "help-echo");
   DEFSYM (Qhelp_echo_inhibit_substitution, "help-echo-inhibit-substitution");
   DEFSYM (QCrtl, ":rtl");
+  DEFSYM (QCwrap, ":wrap");
 
   staticpro (&item_properties);
   item_properties = Qnil;
diff --git a/src/xdisp.c b/src/xdisp.c
index 43c628b73d8..d09116b3fb5 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -15000,7 +15000,10 @@ update_tool_bar (struct frame *f, bool save_match_data)
 
 /* Set F->desired_tool_bar_string to a Lisp string representing frame
    F's desired tool-bar contents.  F->tool_bar_items must have
-   been set up previously by calling prepare_menu_bars.  */
+   been set up previously by calling prepare_menu_bars.
+
+   Also set F->tool_bar_wraps_p to whether or not the tool bar
+   contains explicit line breaking items.  */
 
 static void
 build_desired_tool_bar_string (struct frame *f)
@@ -15022,9 +15025,11 @@ build_desired_tool_bar_string (struct frame *f)
   size_needed = f->n_tool_bar_items;
 
   /* Reuse f->desired_tool_bar_string, if possible.  */
+
   if (size < size_needed || NILP (f->desired_tool_bar_string))
-    fset_desired_tool_bar_string
-      (f, Fmake_string (make_fixnum (size_needed), make_fixnum (' '), Qnil));
+    /* Don't initialize the contents of this string yet, as they will
+       be set within the loop below.  */
+    fset_desired_tool_bar_string (f, make_uninit_string (size_needed));
   else
     {
       AUTO_LIST4 (props, Qdisplay, Qnil, Qmenu_item, Qnil);
@@ -15032,6 +15037,8 @@ build_desired_tool_bar_string (struct frame *f)
                                props, f->desired_tool_bar_string);
     }
 
+  f->tool_bar_wraps_p = false;
+
   /* Put a `display' property on the string for the images to display,
      put a `menu_item' property on tool-bar items with a value that
      is the index of the item in F's tool-bar item vector.  */
@@ -15044,6 +15051,21 @@ build_desired_tool_bar_string (struct frame *f)
       bool selected_p = !NILP (PROP (TOOL_BAR_ITEM_SELECTED_P));
       int hmargin, vmargin, relief, idx, end;
 
+      if (!NILP (PROP (TOOL_BAR_ITEM_WRAP)))
+        {
+          /* This is a line wrap.  Instead of building a tool bar
+             item, display a new line character instead.  */
+          SSET (f->desired_tool_bar_string, i, '\n');
+
+          /* Set F->tool_bar_wraps_p.  This tells redisplay_tool_bar
+             to allow individual rows to be different heights.  */
+          f->tool_bar_wraps_p = true;
+          continue;
+        }
+
+      /* Replace this with a space character.  */
+      SSET (f->desired_tool_bar_string, i, ' ');
+
       /* If image is a vector, choose the image according to the
          button state.  */
       image = PROP (TOOL_BAR_ITEM_IMAGES);
@@ -15155,6 +15177,16 @@ build_desired_tool_bar_string (struct frame *f)
                             props, f->desired_tool_bar_string);
 #undef PROP
     }
+
+  /* Now replace each character between i and the end of the tool bar
+     string with spaces, to prevent stray newlines from accumulating
+     when the number of tool bar items decreases.  `size' is 0 if the
+     tool bar string is new, but in that case the string will have
+     been completely initialized anyway.  */
+
+  for (; i < size; ++i)
+    /* Replace this with a space character.  */
+    SSET (f->desired_tool_bar_string, i, ' ');
 }
 
 
@@ -15168,7 +15200,10 @@ build_desired_tool_bar_string (struct frame *f)
    If HEIGHT is -1, we are counting needed tool-bar lines, so don't
    count a final empty row in case the tool-bar width exactly matches
    the window width.
-*/
+
+   HEIGHT may also be -1 if there is an explicit line wrapping item
+   inside the tool bar; in that case, allow individual rows of the
+   tool bar to differ in height.  */
 
 static void
 display_tool_bar_line (struct it *it, int height)
@@ -15232,8 +15267,18 @@ display_tool_bar_line (struct it *it, int height)
           ++i;
         }
 
-      /* Stop at line end.  */
+      /* Stop at the end of the iterator, and move to the next line
+         upon a '\n' appearing in the tool bar string.  Tool bar
+         strings may contain multiple new line characters when
+         explicit wrap items are encountered.  */
+
       if (ITERATOR_AT_END_OF_LINE_P (it))
+        {
+          reseat_at_next_visible_line_start (it, false);
+          break;
+        }
+
+      if (ITERATOR_AT_END_P (it))
         break;
 
       set_iterator_to_next (it, true);
@@ -15260,7 +15305,8 @@ display_tool_bar_line (struct it *it, int height)
     last->left_box_line_p = true;
 
   /* Make line the desired height and center it vertically.  */
-  if ((height -= it->max_ascent + it->max_descent) > 0)
+  if (height != -1
+      && (height -= it->max_ascent + it->max_descent) > 0)
     {
       /* Don't add more than one line height.  */
       height %= FRAME_LINE_HEIGHT (it->f);
@@ -15294,6 +15340,7 @@ display_tool_bar_line (struct it *it, int height)
 /* Value is the number of pixels needed to make all tool-bar items of
    frame F visible.  The actual number of glyph rows needed is
    returned in *N_ROWS if non-NULL.  */
+
 static int
 tool_bar_height (struct frame *f, int *n_rows, bool pixelwise)
 {
@@ -15371,7 +15418,9 @@ redisplay_tool_bar (struct frame *f)
   struct window *w;
   struct it it;
   struct glyph_row *row;
+  bool change_height_p;
 
+  change_height_p = false;
   f->tool_bar_redisplayed = true;
 
   /* If frame hasn't a tool-bar window or if it is zero-height, don't
@@ -15455,18 +15504,39 @@ redisplay_tool_bar (struct frame *f)
         border = 0;
 
       rows = f->n_tool_bar_rows;
-      height = max (1, (it.last_visible_y - border) / rows);
-      extra = it.last_visible_y - border - height * rows;
 
-      while (it.current_y < it.last_visible_y)
+      if (f->tool_bar_wraps_p)
         {
-          int h = 0;
-          if (extra > 0 && rows-- > 0)
+          /* If the tool bar contains explicit line wrapping items,
+             don't force each row to have a fixed height.  */
+
+          while (!ITERATOR_AT_END_P (&it))
+            display_tool_bar_line (&it, -1);
+
+          /* Because changes to individual tool bar items may now
+             change the height of the tool bar, adjust the height of
+             the tool bar window if it is different from the tool bar
+             height in any way.  */
+
+          if (it.current_y != it.last_visible_y)
+            change_height_p = true;
+        }
+      else
+        {
+          height = max (1, (it.last_visible_y - border) / rows);
+          extra = it.last_visible_y - border - height * rows;
+
+          while (it.current_y < it.last_visible_y)
             {
-              h = (extra + rows - 1) / rows;
-              extra -= h;
+              int h = 0;
+              if (extra > 0 && rows-- > 0)
+                {
+                  h = (extra + rows - 1) / rows;
+                  extra -= h;
+                }
+          
+              display_tool_bar_line (&it, height + h);
             }
-          display_tool_bar_line (&it, height + h);
         }
     }
   else
@@ -15482,8 +15552,6 @@ redisplay_tool_bar (struct frame *f)
 
   if (!NILP (Vauto_resize_tool_bars))
     {
-      bool change_height_p = false;
-
       /* If we couldn't display everything, change the tool-bar's
          height if there is room for more.  */
       if (IT_STRING_CHARPOS (it) < it.end_charpos)