/* 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 <string.h>
#include <glib/gi18n.h>
#include <gtk/gtk.h>
/* 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 (GdkScreen *screen,
const char *prompt)
{
GdkDisplay *display = gdk_screen_get_display (screen);
GtkWidget *popup, *label, *frame;
GdkCursor *cursor;
GtkWidget *toplevel = NULL;
GdkDevice *device;
popup = gtk_window_new (GTK_WINDOW_POPUP);
gtk_window_set_screen (GTK_WINDOW (popup), screen);
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_all (popup);
cursor = gdk_cursor_new_from_name (display, "crosshair");
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 (gdk_screen_get_display (screen));
if (toplevel == popup)
toplevel = NULL;
}
g_object_unref (cursor);
gtk_widget_destroy (popup);
gdk_flush (); /* Really release the grab */
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)
{
GdkScreen *screen = gtk_widget_get_screen (info->window);
GtkWidget *toplevel;
toplevel = query_for_toplevel (screen,
"Please select the toplevel\n"
"to move to the new screen");
if (toplevel)
gtk_window_set_screen (GTK_WINDOW (toplevel), gdk_display_get_default_screen (info->current_display));
else
gdk_display_beep (gdk_screen_get_display (screen));
}
/* 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);
gtk_widget_show_all (gtk_bin_get_child (GTK_BIN (dialog)));
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);
gtk_container_set_border_width (GTK_CONTAINER (hbox), 8);
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, TRUE, TRUE, 0);
*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, FALSE, FALSE, 0);
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, FALSE, FALSE, 0);
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, FALSE, FALSE, 0);
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);
gtk_container_set_border_width (GTK_CONTAINER (vbox), 8);
gtk_box_pack_start (GTK_BOX (content_area), vbox, TRUE, TRUE, 0);
frame = create_display_frame (info);
gtk_box_pack_start (GTK_BOX (vbox), frame, TRUE, TRUE, 0);
initialize_displays (info);
gtk_widget_show_all (info->window);
return info->window;
}
else
{
gtk_widget_destroy (info->window);
return NULL;
}
}