GTK: First draft of the unified cut/copy/paste and +/-/Fullscreen menu items.

chrome/browser/gtk/gtk_custom_menu_item.h

+// Copyright (c) 2010 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 CHROME_BROWSER_GTK_GTK_CUSTOM_MENU_ITEM_H_
+#define CHROME_BROWSER_GTK_GTK_CUSTOM_MENU_ITEM_H_
+
+// GtkCustomMenuItem is a GtkMenuItem subclass that has buttons in it and acts
+// to support this. GtkCustomMenuItems only render properly when put in a
+// GtkCustomMenu; there's a lot of collaboration between these two classes
+// necessary to work around how gtk normally does menus.
+//
+// We can't rely on the normal event infrastructure. While a menu is up, the
+// GtkMenu has a grab on all events. Instead of trying to pump events through
+// the normal channels, we have the GtkCustomMenu selectively forward mouse
+// motion through a back channel. The GtkCustomMenu only listens for button
+// press information so it can block the effects of the click if the cursor
+// isn't in a button in the menu item.
+//
+// A GtkCustomMenuItem doesn't try to take these signals and forward them to
+// the buttons it owns. The GtkCustomMenu class keeps track of which button is
+// selected (due to key events and mouse movement) and otherwise acts like a
+// normal GtkItem. The buttons are only for sizing and rendering; they don't
+// respond to events. Instead, when the GtkCustomMenuItem is activated by the
+// GtkMenu, it uses which button was selected as a signal of what to do.
+//
+// Users should connect to the "button-pushed" signal to be notified when a
+// button was pushed. We don't go through the normal "activate" signal because
+// we need to communicate additional information, namely which button was
+// activated.
+
+#include <gdk/gdk.h>
+#include <gtk/gtk.h>
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_CUSTOM_MENU_ITEM                                       \
+  (gtk_custom_menu_item_get_type())
+#define GTK_CUSTOM_MENU_ITEM(obj)                                       \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj), GTK_TYPE_CUSTOM_MENU_ITEM,         \
+                              GtkCustomMenuItem))
+#define GTK_CUSTOM_MENU_ITEM_CLASS(klass)                               \
+  (G_TYPE_CHECK_CLASS_CAST((klass), GTK_TYPE_CUSTOM_MENU_ITEM,          \
+                           GtkCustomMenuItemClass))
+#define GTK_IS_CUSTOM_MENU_ITEM(obj)                                    \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj), GTK_TYPE_CUSTOM_MENU_ITEM))
+#define GTK_IS_CUSTOM_MENU_ITEM_CLASS(klass)                            \
+  (G_TYPE_CHECK_CLASS_TYPE((klass), GTK_TYPE_CUSTOM_MENU_ITEM))
+#define GTK_CUSTOM_MENU_ITEM_GET_CLASS(obj)                             \
+  (G_TYPE_INSTANCE_GET_CLASS((obj), GTK_TYPE_CUSTOM_MENU_ITEM,          \
+                             GtkCustomMenuItemClass))
+
+typedef struct _GtkCustomMenuItem GtkCustomMenuItem;
+typedef struct _GtkCustomMenuItemClass GtkCustomMenuItemClass;
+
+struct _GtkCustomMenuItem {
+  GtkMenuItem menu_item;
+
+  // Container for button widgets.
+  GtkWidget* hbox;
+
+  // Label on left side of menu item.
+  GtkWidget* label;
+
+  // Possible button widgets
+  GList* button_widgets;
+
+  // The widget that currently has highlight.
+  GtkWidget* currently_selected_button;
+
+  // The widget that was selected *before* |currently_selected_button|. Why do
+  // we hang on to this? Because the menu system sends us a deselect signal
+  // right before activating us. We need to listen to deselect since that's
+  // what we receive when the mouse cursor leaves us entirely.
+  GtkWidget* previously_selected_button;
+};
+
+struct _GtkCustomMenuItemClass {
+  GtkMenuItemClass parent_class;
+};
+
+GType gtk_custom_menu_item_get_type(void) G_GNUC_CONST;
+GtkWidget* gtk_custom_menu_item_new(const char* title);
+
+// Adds a button to our list of items in the |hbox|.
+GtkWidget* gtk_custom_menu_item_add_button(GtkCustomMenuItem* menu_item,
+                                           int command_id);
+
+// Adds a vertical space in the |hbox|.
+void gtk_custom_menu_item_add_space(GtkCustomMenuItem* menu_item);
+
+// Receives a motion event from the GtkCustomMenu that contains us. We can't
+// just subscribe to motion-event or the individual widget enter/leave events
+// because the top level GtkMenu has an event grab.
+void gtk_custom_menu_item_receive_motion_event(GtkCustomMenuItem* menu_item,
+                                               gdouble x, gdouble y);
+
+// Notification that the menu got a cursor key event. Used to move up/down
+// within the menu buttons. Returns TRUE to stop the default signal handler
+// from running.
+gboolean gtk_custom_menu_item_handle_move(GtkCustomMenuItem* menu_item,
+                                          GtkMenuDirectionType direction);
+
+// Because we only get a generic "selected" signal when we've changed, we need
+// to have a way for the GtkCustomMenu to tell us that we were just
+// selected.
+void gtk_custom_menu_item_select_item_by_direction(
+    GtkCustomMenuItem* menu_item, GtkMenuDirectionType direction);
+
+// Whether we are currently hovering over a clickable region on the menu
+// item. Used by GtkCustomMenu to determine whether it should discard click
+// events.
+gboolean gtk_custom_menu_item_is_in_clickable_region(
+    GtkCustomMenuItem* menu_item);
+
+G_END_DECLS
+
+#endif  // CHROME_BROWSER_GTK_GTK_CUSTOM_MENU_ITEM_H_