/* Change Display * * Demonstrates migrating a window between different displays. * A display is a mouse and keyboard with some number of * associated monitors. The neat thing about having multiple * displays is that they can be on a completely separate * computers, as long as there is a network connection to the * computer where the application is running. * * Only some of the windowing systems where GTK+ runs have the * concept of multiple displays. (The X Window System is the * main example.) Other windowing systems can only handle one * keyboard and mouse, and combine all monitors into * a single display. * * This is a moderately complex example, and demonstrates: * * - Tracking the currently open displays * * - Changing the display for a window * * - Letting the user choose a window by clicking on it * * - Using GtkListStore and GtkTreeView * * - Using GtkDialog */ #include #include #include /* The ChangeDisplayInfo structure corresponds to a toplevel window and * holds pointers to widgets inside the toplevel window along with other * information about the contents of the window. * This is a common organizational structure in real applications. */ typedef struct _ChangeDisplayInfo ChangeDisplayInfo; struct _ChangeDisplayInfo { GtkWidget *window; GtkSizeGroup *size_group; GtkTreeModel *display_model; GdkDisplay *current_display; }; /* These enumerations provide symbolic names for the columns * in the two GtkListStore models. */ enum { DISPLAY_COLUMN_NAME, DISPLAY_COLUMN_DISPLAY, DISPLAY_NUM_COLUMNS }; enum { SCREEN_COLUMN_NUMBER, SCREEN_COLUMN_SCREEN, SCREEN_NUM_COLUMNS }; /* Finds the toplevel window under the mouse pointer, if any. */ static GtkWidget * find_toplevel_at_pointer (GdkDisplay *display) { GdkWindow *pointer_window; GtkWidget *widget = NULL; pointer_window = gdk_device_get_window_at_position (gtk_get_current_event_device (), NULL, NULL); /* The user data field of a GdkWindow is used to store a pointer * to the widget that created it. */ if (pointer_window) { gpointer widget_ptr; gdk_window_get_user_data (pointer_window, &widget_ptr); widget = widget_ptr; } return widget ? gtk_widget_get_toplevel (widget) : NULL; } static gboolean button_release_event_cb (GtkWidget *widget, GdkEventButton *event, gboolean *clicked) { *clicked = TRUE; return TRUE; } /* Asks the user to click on a window, then waits for them click * the mouse. When the mouse is released, returns the toplevel * window under the pointer, or NULL, if there is none. */ static GtkWidget * query_for_toplevel (GdkDisplay *display, const char *prompt) { GtkWidget *popup, *label, *frame; GdkCursor *cursor; GtkWidget *toplevel = NULL; GdkDevice *device; popup = gtk_window_new (GTK_WINDOW_POPUP); gtk_window_set_display (GTK_WINDOW (popup), display); gtk_window_set_modal (GTK_WINDOW (popup), TRUE); gtk_window_set_position (GTK_WINDOW (popup), GTK_WIN_POS_CENTER); frame = gtk_frame_new (NULL); gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_OUT); gtk_container_add (GTK_CONTAINER (popup), frame); label = gtk_label_new (prompt); g_object_set (label, "margin", 10, NULL); gtk_container_add (GTK_CONTAINER (frame), label); gtk_widget_show (popup); cursor = gdk_cursor_new_from_name ("crosshair", NULL); device = gtk_get_current_event_device (); if (gdk_seat_grab (gdk_device_get_seat (device), gtk_widget_get_window (popup), GDK_SEAT_CAPABILITY_ALL_POINTING, FALSE, cursor, NULL, NULL, NULL) == GDK_GRAB_SUCCESS) { gboolean clicked = FALSE; g_signal_connect (popup, "button-release-event", G_CALLBACK (button_release_event_cb), &clicked); /* Process events until clicked is set by button_release_event_cb. * We pass in may_block=TRUE since we want to wait if there * are no events currently. */ while (!clicked) g_main_context_iteration (NULL, TRUE); toplevel = find_toplevel_at_pointer (display); if (toplevel == popup) toplevel = NULL; } g_object_unref (cursor); gtk_widget_destroy (popup); return toplevel; } /* Prompts the user for a toplevel window to move, and then moves * that window to the currently selected display */ static void query_change_display (ChangeDisplayInfo *info) { GdkDisplay *display = gtk_widget_get_display (info->window); GtkWidget *toplevel; toplevel = query_for_toplevel (display, "Please select the toplevel\n" "to move to the new display"); if (toplevel) gtk_window_set_display (GTK_WINDOW (toplevel), info->current_display); else gdk_display_beep (display); } /* Called when the user clicks on a button in our dialog or * closes the dialog through the window manager. Unless the * "Change" button was clicked, we destroy the dialog. */ static void response_cb (GtkDialog *dialog, gint response_id, ChangeDisplayInfo *info) { if (response_id == GTK_RESPONSE_OK) query_change_display (info); else gtk_widget_destroy (GTK_WIDGET (dialog)); } /* Called when the user clicks on "Open..." in the display * frame. Prompts for a new display, and then opens a connection * to that display. */ static void open_display_cb (GtkWidget *button, ChangeDisplayInfo *info) { GtkWidget *content_area; GtkWidget *dialog; GtkWidget *display_entry; GtkWidget *dialog_label; gchar *new_screen_name = NULL; GdkDisplay *result = NULL; dialog = gtk_dialog_new_with_buttons ("Open Display", GTK_WINDOW (info->window), GTK_DIALOG_MODAL, _("_Cancel"), GTK_RESPONSE_CANCEL, _("_OK"), GTK_RESPONSE_OK, NULL); gtk_dialog_set_default_response (GTK_DIALOG (dialog), GTK_RESPONSE_OK); display_entry = gtk_entry_new (); gtk_entry_set_activates_default (GTK_ENTRY (display_entry), TRUE); dialog_label = gtk_label_new ("Please enter the name of\nthe new display\n"); content_area = gtk_dialog_get_content_area (GTK_DIALOG (dialog)); gtk_container_add (GTK_CONTAINER (content_area), dialog_label); gtk_container_add (GTK_CONTAINER (content_area), display_entry); gtk_widget_grab_focus (display_entry); while (!result) { gint response_id = gtk_dialog_run (GTK_DIALOG (dialog)); if (response_id != GTK_RESPONSE_OK) break; new_screen_name = gtk_editable_get_chars (GTK_EDITABLE (display_entry), 0, -1); if (strcmp (new_screen_name, "") != 0) { result = gdk_display_open (new_screen_name); if (!result) { gchar *error_msg = g_strdup_printf ("Can't open display:\n\t%s\nplease try another one\n", new_screen_name); gtk_label_set_text (GTK_LABEL (dialog_label), error_msg); g_free (error_msg); } g_free (new_screen_name); } } gtk_widget_destroy (dialog); } /* Called when the user clicks on the "Close" button in the * "Display" frame. Closes the selected display. */ static void close_display_cb (GtkWidget *button, ChangeDisplayInfo *info) { if (info->current_display) gdk_display_close (info->current_display); } /* Called when the selected row in the display list changes. * Updates info->current_display, then refills the list of * screens. */ static void display_changed_cb (GtkTreeSelection *selection, ChangeDisplayInfo *info) { GtkTreeModel *model; GtkTreeIter iter; if (info->current_display) g_object_unref (info->current_display); if (gtk_tree_selection_get_selected (selection, &model, &iter)) gtk_tree_model_get (model, &iter, DISPLAY_COLUMN_DISPLAY, &info->current_display, -1); else info->current_display = NULL; } /* This function is used both for creating the "Display" and * "Screen" frames, since they have a similar structure. The * caller hooks up the right context for the value returned * in tree_view, and packs any relevant buttons into button_vbox. */ static void create_frame (ChangeDisplayInfo *info, const char *title, GtkWidget **frame, GtkWidget **tree_view, GtkWidget **button_vbox) { GtkTreeSelection *selection; GtkWidget *scrollwin; GtkWidget *hbox; *frame = gtk_frame_new (title); hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 8); g_object_set (hbox, "margin", 8, NULL); gtk_container_add (GTK_CONTAINER (*frame), hbox); scrollwin = gtk_scrolled_window_new (NULL, NULL); gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrollwin), GTK_POLICY_NEVER, GTK_POLICY_AUTOMATIC); gtk_scrolled_window_set_shadow_type (GTK_SCROLLED_WINDOW (scrollwin), GTK_SHADOW_IN); gtk_box_pack_start (GTK_BOX (hbox), scrollwin); *tree_view = gtk_tree_view_new (); gtk_tree_view_set_headers_visible (GTK_TREE_VIEW (*tree_view), FALSE); gtk_container_add (GTK_CONTAINER (scrollwin), *tree_view); selection = gtk_tree_view_get_selection (GTK_TREE_VIEW (*tree_view)); gtk_tree_selection_set_mode (selection, GTK_SELECTION_BROWSE); *button_vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 5); gtk_box_pack_start (GTK_BOX (hbox), *button_vbox); if (!info->size_group) info->size_group = gtk_size_group_new (GTK_SIZE_GROUP_HORIZONTAL); gtk_size_group_add_widget (GTK_SIZE_GROUP (info->size_group), *button_vbox); } /* If we have a stack of buttons, it often looks better if their contents * are left-aligned, rather than centered. This function creates a button * and left-aligns it contents. */ GtkWidget * left_align_button_new (const char *label) { GtkWidget *button = gtk_button_new_with_mnemonic (label); GtkWidget *child = gtk_bin_get_child (GTK_BIN (button)); gtk_widget_set_halign (child, GTK_ALIGN_START); gtk_widget_set_valign (child, GTK_ALIGN_CENTER); return button; } /* Creates the "Display" frame in the main window. */ GtkWidget * create_display_frame (ChangeDisplayInfo *info) { GtkWidget *frame; GtkWidget *tree_view; GtkWidget *button_vbox; GtkTreeViewColumn *column; GtkTreeSelection *selection; GtkWidget *button; create_frame (info, "Display", &frame, &tree_view, &button_vbox); button = left_align_button_new ("_Open..."); g_signal_connect (button, "clicked", G_CALLBACK (open_display_cb), info); gtk_box_pack_start (GTK_BOX (button_vbox), button); button = left_align_button_new ("_Close"); g_signal_connect (button, "clicked", G_CALLBACK (close_display_cb), info); gtk_box_pack_start (GTK_BOX (button_vbox), button); info->display_model = (GtkTreeModel *)gtk_list_store_new (DISPLAY_NUM_COLUMNS, G_TYPE_STRING, GDK_TYPE_DISPLAY); gtk_tree_view_set_model (GTK_TREE_VIEW (tree_view), info->display_model); column = gtk_tree_view_column_new_with_attributes ("Name", gtk_cell_renderer_text_new (), "text", DISPLAY_COLUMN_NAME, NULL); gtk_tree_view_append_column (GTK_TREE_VIEW (tree_view), column); selection = gtk_tree_view_get_selection (GTK_TREE_VIEW (tree_view)); g_signal_connect (selection, "changed", G_CALLBACK (display_changed_cb), info); return frame; } /* Called when one of the currently open displays is closed. * Remove it from our list of displays. */ static void display_closed_cb (GdkDisplay *display, gboolean is_error, ChangeDisplayInfo *info) { GtkTreeIter iter; gboolean valid; for (valid = gtk_tree_model_get_iter_first (info->display_model, &iter); valid; valid = gtk_tree_model_iter_next (info->display_model, &iter)) { GdkDisplay *tmp_display; gtk_tree_model_get (info->display_model, &iter, DISPLAY_COLUMN_DISPLAY, &tmp_display, -1); if (tmp_display == display) { gtk_list_store_remove (GTK_LIST_STORE (info->display_model), &iter); break; } } } /* Adds a new display to our list of displays, and connects * to the "closed" signal so that we can remove it from the * list of displays again. */ static void add_display (ChangeDisplayInfo *info, GdkDisplay *display) { const gchar *name = gdk_display_get_name (display); GtkTreeIter iter; gtk_list_store_append (GTK_LIST_STORE (info->display_model), &iter); gtk_list_store_set (GTK_LIST_STORE (info->display_model), &iter, DISPLAY_COLUMN_NAME, name, DISPLAY_COLUMN_DISPLAY, display, -1); g_signal_connect (display, "closed", G_CALLBACK (display_closed_cb), info); } /* Called when a new display is opened */ static void display_opened_cb (GdkDisplayManager *manager, GdkDisplay *display, ChangeDisplayInfo *info) { add_display (info, display); } /* Adds all currently open displays to our list of displays, * and set up a signal connection so that we'll be notified * when displays are opened in the future as well. */ static void initialize_displays (ChangeDisplayInfo *info) { GdkDisplayManager *manager = gdk_display_manager_get (); GSList *displays = gdk_display_manager_list_displays (manager); GSList *tmp_list; for (tmp_list = displays; tmp_list; tmp_list = tmp_list->next) add_display (info, tmp_list->data); g_slist_free (tmp_list); g_signal_connect (manager, "display-opened", G_CALLBACK (display_opened_cb), info); } /* Cleans up when the toplevel is destroyed; we remove the * connections we use to track currently open displays, then * free the ChangeDisplayInfo structure. */ static void destroy_info (ChangeDisplayInfo *info) { GdkDisplayManager *manager = gdk_display_manager_get (); GSList *displays = gdk_display_manager_list_displays (manager); GSList *tmp_list; g_signal_handlers_disconnect_by_func (manager, display_opened_cb, info); for (tmp_list = displays; tmp_list; tmp_list = tmp_list->next) g_signal_handlers_disconnect_by_func (tmp_list->data, display_closed_cb, info); g_slist_free (tmp_list); g_object_unref (info->size_group); g_object_unref (info->display_model); if (info->current_display) g_object_unref (info->current_display); g_free (info); } static void destroy_cb (GObject *object, ChangeDisplayInfo **info) { destroy_info (*info); *info = NULL; } /* Main entry point. If the dialog for this demo doesn't yet exist, creates * it. Otherwise, destroys it. */ GtkWidget * do_changedisplay (GtkWidget *do_widget) { static ChangeDisplayInfo *info = NULL; if (!info) { GtkWidget *content_area; GtkWidget *vbox; GtkWidget *frame; info = g_new0 (ChangeDisplayInfo, 1); info->window = gtk_dialog_new_with_buttons ("Change Display", GTK_WINDOW (do_widget), 0, "Close", GTK_RESPONSE_CLOSE, "Change", GTK_RESPONSE_OK, NULL); gtk_window_set_default_size (GTK_WINDOW (info->window), 300, 400); g_signal_connect (info->window, "response", G_CALLBACK (response_cb), info); g_signal_connect (info->window, "destroy", G_CALLBACK (destroy_cb), &info); content_area = gtk_dialog_get_content_area (GTK_DIALOG (info->window)); vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 5); g_object_set (vbox, "margin", 8, NULL); gtk_box_pack_start (GTK_BOX (content_area), vbox); frame = create_display_frame (info); gtk_box_pack_start (GTK_BOX (vbox), frame); initialize_displays (info); gtk_widget_show (info->window); return info->window; } else { gtk_widget_destroy (info->window); return NULL; } }