1// Copyright (c) 2011 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef CHROME_BROWSER_UI_GTK_GTK_CUSTOM_MENU_ITEM_H_
6#define CHROME_BROWSER_UI_GTK_GTK_CUSTOM_MENU_ITEM_H_
7#pragma once
8
9// GtkCustomMenuItem is a GtkMenuItem subclass that has buttons in it and acts
10// to support this. GtkCustomMenuItems only render properly when put in a
11// GtkCustomMenu; there's a lot of collaboration between these two classes
12// necessary to work around how gtk normally does menus.
13//
14// We can't rely on the normal event infrastructure. While a menu is up, the
15// GtkMenu has a grab on all events. Instead of trying to pump events through
16// the normal channels, we have the GtkCustomMenu selectively forward mouse
17// motion through a back channel. The GtkCustomMenu only listens for button
18// press information so it can block the effects of the click if the cursor
19// isn't in a button in the menu item.
20//
21// A GtkCustomMenuItem doesn't try to take these signals and forward them to
22// the buttons it owns. The GtkCustomMenu class keeps track of which button is
23// selected (due to key events and mouse movement) and otherwise acts like a
24// normal GtkItem. The buttons are only for sizing and rendering; they don't
25// respond to events. Instead, when the GtkCustomMenuItem is activated by the
26// GtkMenu, it uses which button was selected as a signal of what to do.
27//
28// Users should connect to the "button-pushed" signal to be notified when a
29// button was pushed. We don't go through the normal "activate" signal because
30// we need to communicate additional information, namely which button was
31// activated.
32
33#include <gdk/gdk.h>
34#include <gtk/gtk.h>
35
36G_BEGIN_DECLS
37
38#define GTK_TYPE_CUSTOM_MENU_ITEM                                       \
39  (gtk_custom_menu_item_get_type())
40#define GTK_CUSTOM_MENU_ITEM(obj)                                       \
41  (G_TYPE_CHECK_INSTANCE_CAST((obj), GTK_TYPE_CUSTOM_MENU_ITEM,         \
42                              GtkCustomMenuItem))
43#define GTK_CUSTOM_MENU_ITEM_CLASS(klass)                               \
44  (G_TYPE_CHECK_CLASS_CAST((klass), GTK_TYPE_CUSTOM_MENU_ITEM,          \
45                           GtkCustomMenuItemClass))
46#define GTK_IS_CUSTOM_MENU_ITEM(obj)                                    \
47  (G_TYPE_CHECK_INSTANCE_TYPE((obj), GTK_TYPE_CUSTOM_MENU_ITEM))
48#define GTK_IS_CUSTOM_MENU_ITEM_CLASS(klass)                            \
49  (G_TYPE_CHECK_CLASS_TYPE((klass), GTK_TYPE_CUSTOM_MENU_ITEM))
50#define GTK_CUSTOM_MENU_ITEM_GET_CLASS(obj)                             \
51  (G_TYPE_INSTANCE_GET_CLASS((obj), GTK_TYPE_CUSTOM_MENU_ITEM,          \
52                             GtkCustomMenuItemClass))
53
54typedef struct _GtkCustomMenuItem GtkCustomMenuItem;
55typedef struct _GtkCustomMenuItemClass GtkCustomMenuItemClass;
56
57struct _GtkCustomMenuItem {
58  GtkMenuItem menu_item;
59
60  // Container for button widgets.
61  GtkWidget* hbox;
62
63  // Label on left side of menu item.
64  GtkWidget* label;
65
66  // List of all widgets we added. Used to find the leftmost and rightmost
67  // continuous buttons.
68  GList* all_widgets;
69
70  // Possible button widgets. Used for keyboard navigation.
71  GList* button_widgets;
72
73  // The widget that currently has highlight.
74  GtkWidget* currently_selected_button;
75
76  // The widget that was selected *before* |currently_selected_button|. Why do
77  // we hang on to this? Because the menu system sends us a deselect signal
78  // right before activating us. We need to listen to deselect since that's
79  // what we receive when the mouse cursor leaves us entirely.
80  GtkWidget* previously_selected_button;
81};
82
83struct _GtkCustomMenuItemClass {
84  GtkMenuItemClass parent_class;
85};
86
87GType gtk_custom_menu_item_get_type(void) G_GNUC_CONST;
88GtkWidget* gtk_custom_menu_item_new(const char* title);
89
90// Adds a button to our list of items in the |hbox|.
91GtkWidget* gtk_custom_menu_item_add_button(GtkCustomMenuItem* menu_item,
92                                           int command_id);
93
94// Adds a button to our list of items in the |hbox|, but that isn't part of
95// |button_widgets| to prevent it from being activatable.
96GtkWidget* gtk_custom_menu_item_add_button_label(GtkCustomMenuItem* menu_item,
97                                                 int command_id);
98
99// Adds a vertical space in the |hbox|.
100void gtk_custom_menu_item_add_space(GtkCustomMenuItem* menu_item);
101
102// Receives a motion event from the GtkCustomMenu that contains us. We can't
103// just subscribe to motion-event or the individual widget enter/leave events
104// because the top level GtkMenu has an event grab.
105void gtk_custom_menu_item_receive_motion_event(GtkCustomMenuItem* menu_item,
106                                               gdouble x, gdouble y);
107
108// Notification that the menu got a cursor key event. Used to move up/down
109// within the menu buttons. Returns TRUE to stop the default signal handler
110// from running.
111gboolean gtk_custom_menu_item_handle_move(GtkCustomMenuItem* menu_item,
112                                          GtkMenuDirectionType direction);
113
114// Because we only get a generic "selected" signal when we've changed, we need
115// to have a way for the GtkCustomMenu to tell us that we were just
116// selected.
117void gtk_custom_menu_item_select_item_by_direction(
118    GtkCustomMenuItem* menu_item, GtkMenuDirectionType direction);
119
120// Whether we are currently hovering over a clickable region on the menu
121// item. Used by GtkCustomMenu to determine whether it should discard click
122// events.
123gboolean gtk_custom_menu_item_is_in_clickable_region(
124    GtkCustomMenuItem* menu_item);
125
126// If the button is released while the |currently_selected_button| isn't
127// supposed to dismiss the menu, this signals to our listeners that we want to
128// run this command if it doesn't dismiss the menu.  Returns TRUE if we acted
129// on this button click (and should prevent the normal GtkMenu machinery from
130// firing an "activate" signal).
131gboolean gtk_custom_menu_item_try_no_dismiss_command(
132    GtkCustomMenuItem* menu_item);
133
134// Calls |callback| with every button and button-label in the container.
135void gtk_custom_menu_item_foreach_button(GtkCustomMenuItem* menu_item,
136                                         GtkCallback callback,
137                                         gpointer callback_data);
138
139G_END_DECLS
140
141#endif  // CHROME_BROWSER_UI_GTK_GTK_CUSTOM_MENU_ITEM_H_
142