A new menu system.

views/controls/menu/menu_2.h

+// Copyright (c) 2009 The Chromium Authors. All rights reserved. Use of this
+// source code is governed by a BSD-style license that can be found in the
+// LICENSE file.
+
+#ifndef CONTROLS_MENU_VIEWS_MENU_2_H_
+#define CONTROLS_MENU_VIEWS_MENU_2_H_
+
+#include <string>
+
+#include "base/gfx/native_widget_types.h"
+
+namespace gfx {
+class Point;
+}
+class SkBitmap;
+
+namespace views {
+
+class Accelerator;
+class Menu2;
+class MenuWrapper;
+
+// The Menu2Model is an interface implemented by an object that provides the
+// content of a menu.
+class Menu2Model {
+ public:
+  virtual ~Menu2Model() {}
+
+  // The type of item.
+  enum ItemType {
+    TYPE_COMMAND,
+    TYPE_CHECK,
+    TYPE_RADIO,
+    TYPE_SEPARATOR,
+    TYPE_SUBMENU
+  };
+
+  // Returns true if any of the items within the model have icons. Not all
+  // platforms support icons in menus natively and so this is a hint for
+  // triggering a custom rendering mode.
+  virtual bool HasIcons() const = 0;
+
+  // Returns the index of the first item. This is 0 for most menus except the
+  // system menu on Windows. |native_menu| is the menu to locate the start index
+  // within. It is guaranteed to be reset to a clean default state.
+  // IMPORTANT: If the model implementation returns something _other_ than 0
+  //            here, it must offset the values for |index| it passes to the
+  //            methods below by this number - this is NOT done automatically!
+  virtual int GetFirstItemIndex(gfx::NativeMenu native_menu) const { return 0; }
+
+  // Returns the number of items in the menu.
+  virtual int GetItemCount() const = 0;
+
+  // Returns the type of item at the specified index.
+  virtual ItemType GetTypeAt(int index) const = 0;
+
+  // Returns the command id of the item at the specified index.
+  virtual int GetCommandIdAt(int index) const = 0;
+
+  // Returns the label of the item at the specified index.
+  virtual std::wstring GetLabelAt(int index) const = 0;
+
+  // Returns true if the label at the specified index can change over the course
+  // of the menu's lifetime. If this function returns true, the label of the
+  // menu item will be updated each time the menu is shown.
+  virtual bool IsLabelDynamicAt(int index) const = 0;
+
+  // Gets the acclerator information for the specified index, returning true if
+  // there is a shortcut accelerator for the item, false otherwise.
+  virtual bool GetAcceleratorAt(int index,
+                                views::Accelerator* accelerator) const = 0;
+
+  // Returns the checked state of the item at the specified index.
+  virtual bool IsItemCheckedAt(int index) const = 0;
+
+  // Returns the id of the group of radio items that the item at the specified
+  // index belongs to.
+  virtual int GetGroupIdAt(int index) const = 0;
+
+  // Gets the icon for the item at the specified index, returning true if there
+  // is an icon, false otherwise.
+  virtual bool GetIconAt(int index, SkBitmap* icon) const = 0;
+
+  // Returns the enabled state of the item at the specified index.
+  virtual bool IsEnabledAt(int index) const = 0;
+
+  // Returns the model for the submenu at the specified index.
+  virtual Menu2Model* GetSubmenuModelAt(int index) const = 0;
+
+  // Retrieves the model and index that contains a specific command id. Returns
+  // true if an item with the specified command id is found. |model| is inout,
+  // and specifies the model to start searching from.
+  static bool GetModelAndIndexForCommandId(int command_id, Menu2Model** model,
+                                           int* index);
+};
+
+// The Menu2Delegate is an interface implemented by an object that performs
+// tasks that the Menu2 cannot itself.
+class Menu2Delegate {
+ public:
+  // Executes the command with the specified identifier.
+  virtual void ExecuteCommand(Menu2Model* model, int command_id) = 0;
+};
+
+// A menu. Populated from a model, and relies on a delegate to execute commands.
+class Menu2 {
+ public:
+  Menu2(Menu2Model* model, Menu2Delegate* delegate);
+  virtual ~Menu2() {}
+
+  // How the menu is aligned relative to the point it is shown at.
+  enum Alignment {
+    ALIGN_TOPLEFT,
+    ALIGN_TOPRIGHT
+  };
+
+  // Runs the menu at the specified point. This may or may not block, depending
+  // on the platform and type of menu in use.
+  void RunMenuAt(const gfx::Point& point, Alignment alignment);
+
+  // Called when the model supplying data to this menu has changed, and the menu
+  // must be rebuilt.
+  void Rebuild();
+
+  // Called when the states of the menu items in the menu should be refreshed
+  // from the model.
+  void UpdateStates();
+
+  // For submenus.
+  gfx::NativeMenu GetNativeMenu() const;
+
+  // Accessors.
+  Menu2Model* model() const { return model_; }
+  Menu2Delegate* delegate() const { return delegate_; }
+
+ private:
+  Menu2Model* model_;
+  Menu2Delegate* delegate_;
+
+  // The object that actually implements the menu.
+  MenuWrapper* wrapper_;
+
+  DISALLOW_COPY_AND_ASSIGN(Menu2);
+};
+
+}  // namespace views
+
+#endif  // CONTROLS_MENU_VIEWS_MENU_2_H_