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      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 #include "chrome/browser/ui/gtk/menu_bar_helper.h"
      6 
      7 #include <algorithm>
      8 
      9 #include "base/logging.h"
     10 #include "chrome/browser/ui/gtk/gtk_util.h"
     11 #include "ui/base/gtk/gtk_signal_registrar.h"
     12 
     13 namespace {
     14 
     15 // Recursively find all the GtkMenus that are attached to menu item |child|
     16 // and add them to |data|, which is a vector of GtkWidgets.
     17 void PopulateSubmenus(GtkWidget* child, gpointer data) {
     18   std::vector<GtkWidget*>* submenus =
     19       static_cast<std::vector<GtkWidget*>*>(data);
     20   GtkWidget* submenu = gtk_menu_item_get_submenu(GTK_MENU_ITEM(child));
     21   if (submenu) {
     22     submenus->push_back(submenu);
     23     gtk_container_foreach(GTK_CONTAINER(submenu), PopulateSubmenus, submenus);
     24   }
     25 }
     26 
     27 // Is the cursor over |menu| or one of its parent menus?
     28 bool MotionIsOverMenu(GtkWidget* menu, GdkEventMotion* motion) {
     29   if (motion->x >= 0 && motion->y >= 0 &&
     30       motion->x < menu->allocation.width &&
     31       motion->y < menu->allocation.height) {
     32     return true;
     33   }
     34 
     35   while (menu) {
     36     GtkWidget* menu_item = gtk_menu_get_attach_widget(GTK_MENU(menu));
     37     if (!menu_item)
     38       return false;
     39     GtkWidget* parent = gtk_widget_get_parent(menu_item);
     40 
     41     if (gtk_util::WidgetContainsCursor(parent))
     42       return true;
     43     menu = parent;
     44   }
     45 
     46   return false;
     47 }
     48 
     49 }  // namespace
     50 
     51 MenuBarHelper::MenuBarHelper(Delegate* delegate)
     52     : button_showing_menu_(NULL),
     53       showing_menu_(NULL),
     54       delegate_(delegate) {
     55   DCHECK(delegate_);
     56 }
     57 
     58 MenuBarHelper::~MenuBarHelper() {
     59 }
     60 
     61 void MenuBarHelper::Add(GtkWidget* button) {
     62   buttons_.push_back(button);
     63 }
     64 
     65 void MenuBarHelper::Remove(GtkWidget* button) {
     66   std::vector<GtkWidget*>::iterator iter =
     67       find(buttons_.begin(), buttons_.end(), button);
     68   if (iter == buttons_.end()) {
     69     NOTREACHED();
     70     return;
     71   }
     72   buttons_.erase(iter);
     73 }
     74 
     75 void MenuBarHelper::Clear() {
     76   buttons_.clear();
     77 }
     78 
     79 void MenuBarHelper::MenuStartedShowing(GtkWidget* button, GtkWidget* menu) {
     80   DCHECK(GTK_IS_MENU(menu));
     81   button_showing_menu_ = button;
     82   showing_menu_ = menu;
     83 
     84   signal_handlers_.reset(new ui::GtkSignalRegistrar());
     85   signal_handlers_->Connect(menu, "destroy",
     86                             G_CALLBACK(OnMenuHiddenOrDestroyedThunk), this);
     87   signal_handlers_->Connect(menu, "hide",
     88                             G_CALLBACK(OnMenuHiddenOrDestroyedThunk), this);
     89   signal_handlers_->Connect(menu, "motion-notify-event",
     90                             G_CALLBACK(OnMenuMotionNotifyThunk), this);
     91   signal_handlers_->Connect(menu, "move-current",
     92                             G_CALLBACK(OnMenuMoveCurrentThunk), this);
     93   gtk_container_foreach(GTK_CONTAINER(menu), PopulateSubmenus, &submenus_);
     94 
     95   for (size_t i = 0; i < submenus_.size(); ++i) {
     96     signal_handlers_->Connect(submenus_[i], "motion-notify-event",
     97                               G_CALLBACK(OnMenuMotionNotifyThunk), this);
     98   }
     99 }
    100 
    101 gboolean MenuBarHelper::OnMenuMotionNotify(GtkWidget* menu,
    102                                            GdkEventMotion* motion) {
    103   // Don't do anything if pointer is in the menu.
    104   if (MotionIsOverMenu(menu, motion))
    105     return FALSE;
    106   if (buttons_.empty())
    107     return FALSE;
    108 
    109   gint x = 0;
    110   gint y = 0;
    111   GtkWidget* last_button = NULL;
    112 
    113   for (size_t i = 0; i < buttons_.size(); ++i) {
    114     GtkWidget* button = buttons_[i];
    115     // Figure out coordinates relative to this button. Avoid using
    116     // gtk_widget_get_pointer() unnecessarily.
    117     if (i == 0) {
    118       // We have to make this call because the menu is a popup window, so it
    119       // doesn't share a toplevel with the buttons and we can't just use
    120       // gtk_widget_translate_coordinates().
    121       gtk_widget_get_pointer(buttons_[0], &x, &y);
    122     } else {
    123       gint last_x = x;
    124       gint last_y = y;
    125       if (!gtk_widget_translate_coordinates(
    126           last_button, button, last_x, last_y, &x, &y)) {
    127         // |button| may not be realized.
    128         continue;
    129       }
    130     }
    131 
    132     last_button = button;
    133 
    134     if (x >= 0 && y >= 0 && x < button->allocation.width &&
    135         y < button->allocation.height) {
    136       if (button != button_showing_menu_)
    137         delegate_->PopupForButton(button);
    138       return TRUE;
    139     }
    140   }
    141 
    142   return FALSE;
    143 }
    144 
    145 void MenuBarHelper::OnMenuHiddenOrDestroyed(GtkWidget* menu) {
    146   DCHECK_EQ(showing_menu_, menu);
    147 
    148   signal_handlers_.reset();
    149   showing_menu_ = NULL;
    150   button_showing_menu_ = NULL;
    151   submenus_.clear();
    152 }
    153 
    154 void MenuBarHelper::OnMenuMoveCurrent(GtkWidget* menu,
    155                                       GtkMenuDirectionType dir) {
    156   // The menu directions are triggered by the arrow keys as follows
    157   //
    158   //   PARENT   left
    159   //   CHILD    right
    160   //   NEXT     down
    161   //   PREV     up
    162   //
    163   // We only care about left and right. Note that for RTL, they are swapped.
    164   switch (dir) {
    165     case GTK_MENU_DIR_CHILD: {
    166       GtkWidget* active_item = GTK_MENU_SHELL(menu)->active_menu_item;
    167       // The move is going to open a submenu; don't override default behavior.
    168       if (active_item && gtk_menu_item_get_submenu(GTK_MENU_ITEM(active_item)))
    169         return;
    170       // Fall through.
    171     }
    172     case GTK_MENU_DIR_PARENT: {
    173       delegate_->PopupForButtonNextTo(button_showing_menu_, dir);
    174       break;
    175     }
    176     default:
    177       return;
    178   }
    179 
    180   // This signal doesn't have a return value; we have to manually stop its
    181   // propagation.
    182   g_signal_stop_emission_by_name(menu, "move-current");
    183 }
    184