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GTK+ Reference Manual | ![]() |
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Top | Description |
#include <gtk/gtk.h> gchar * gtk_set_locale (void
); void gtk_disable_setlocale (void
); PangoLanguage * gtk_get_default_language (void
); gboolean gtk_parse_args (int *argc
,char ***argv
); void gtk_init (int *argc
,char ***argv
); gboolean gtk_init_check (int *argc
,char ***argv
); gboolean gtk_init_with_args (gint *argc
,gchar ***argv
,const gchar *parameter_string
,const GOptionEntry *entries
,const gchar *translation_domain
,GError **error
); GOptionGroup * gtk_get_option_group (gboolean open_default_display
); gboolean gtk_events_pending (void
); void gtk_main (void
); guint gtk_main_level (void
); void gtk_main_quit (void
); gboolean gtk_main_iteration (void
); gboolean gtk_main_iteration_do (gboolean blocking
); void gtk_main_do_event (GdkEvent *event
); void (*GtkModuleInitFunc) (gint *argc
,gchar ***argv
); void (*GtkModuleDisplayInitFunc) (GdkDisplay *display
); gboolean gtk_true (void
); gboolean gtk_false (void
); void gtk_grab_add (GtkWidget *widget
); GtkWidget* gtk_grab_get_current (void
); void gtk_grab_remove (GtkWidget *widget
); void gtk_device_grab_add (GtkWidget *widget
,GdkDevice *device
,gboolean block_others
); void gtk_device_grab_remove (GtkWidget *widget
,GdkDevice *device
); gboolean (*GtkFunction) (gpointer data
); void gtk_init_add (GtkFunction function
,gpointer data
); void gtk_quit_add_destroy (guint main_level
,GtkWidget *object
); guint gtk_quit_add (guint main_level
,GtkFunction function
,gpointer data
); void (*GtkCallbackMarshal) (GObject *object
,gpointer data
,guint n_args
,GtkArg *args
); GtkArg; guint gtk_quit_add_full (guint main_level
,GtkFunction function
,GtkCallbackMarshal marshal
,gpointer data
,GDestroyNotify destroy
); void gtk_quit_remove (guint quit_handler_id
); void gtk_quit_remove_by_data (gpointer data
); #define GTK_PRIORITY_RESIZE guint gtk_key_snooper_install (GtkKeySnoopFunc snooper
,gpointer func_data
); gint (*GtkKeySnoopFunc) (GtkWidget *grab_widget
,GdkEventKey *event
,gpointer func_data
); void gtk_key_snooper_remove (guint snooper_handler_id
); GdkEvent* gtk_get_current_event (void
); guint32 gtk_get_current_event_time (void
); gboolean gtk_get_current_event_state (GdkModifierType *state
); GdkDevice * gtk_get_current_event_device (void
); GtkWidget* gtk_get_event_widget (GdkEvent *event
); void gtk_propagate_event (GtkWidget *widget
,GdkEvent *event
);
Before using GTK+, you need to initialize it; initialization connects
to the window system display, and parses some standard command line
arguments. The gtk_init()
function initializes GTK+. gtk_init()
exits
the application if errors occur; to avoid this, use gtk_init_check()
.
gtk_init_check()
allows you to recover from a failed GTK+
initialization - you might start up your application in text mode instead.
Like all GUI toolkits, GTK+ uses an event-driven programming model. When the user is doing nothing, GTK+ sits in the main loop and waits for input. If the user performs some action - say, a mouse click - then the main loop "wakes up" and delivers an event to GTK+. GTK+ forwards the event to one or more widgets.
When widgets receive an event, they frequently emit one or more
signals. Signals notify your program that
"something interesting happened" by invoking functions you've
connected to the signal with g_signal_connect()
. Functions connected
to a signal are often termed callbacks.
When your callbacks are invoked, you would typically take some action - for example, when an Open button is clicked you might display a GtkFileSelectionDialog. After a callback finishes, GTK+ will return to the main loop and await more user input.
Example 2. Typical main
function for a GTK+ application
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 |
int main (int argc, char **argv) { /* Initialize i18n support */ gtk_set_locale (); /* Initialize the widget set */ gtk_init (&argc, &argv); /* Create the main window */ mainwin = gtk_window_new (GTK_WINDOW_TOPLEVEL); /* Set up our GUI elements */ ... /* Show the application window */ gtk_widget_show_all (mainwin); /* Enter the main event loop, and wait for user interaction */ gtk_main (); /* The user lost interest */ return 0; } |
It's OK to use the GLib main loop directly instead of gtk_main()
,
though it involves slightly more typing. See GMainLoop in the GLib
documentation.
gchar * gtk_set_locale (void
);
Initializes internationalization support for GTK+. gtk_init()
automatically does this, so there is typically no point
in calling this function.
If you are calling this function because you changed the locale after GTK+ is was initialized, then calling this function may help a bit. (Note, however, that changing the locale after GTK+ is initialized may produce inconsistent results and is not really supported.)
In detail - sets the current locale according to the
program environment. This is the same as calling the C library function
setlocale (LC_ALL, "")
but also takes care of the
locale specific setup of the windowing system used by GDK.
Returns : |
a string corresponding to the locale set, typically in the
form lang_COUNTRY, where lang is an ISO-639 language code, and
COUNTRY is an ISO-3166 country code. On Unix, this form matches the
result of the setlocale() ; it is also used on other machines, such as
Windows, where the C library returns a different result. The string is
owned by GTK+ and should not be modified or freed.
|
void gtk_disable_setlocale (void
);
Prevents gtk_init()
, gtk_init_check()
, gtk_init_with_args()
and
gtk_parse_args()
from automatically
calling setlocale (LC_ALL, "")
. You would
want to use this function if you wanted to set the locale for
your program to something other than the user's locale, or if
you wanted to set different values for different locale categories.
Most programs should not need to call this function.
PangoLanguage * gtk_get_default_language (void
);
Returns the PangoLanguage for the default language currently in effect. (Note that this can change over the life of an application.) The default language is derived from the current locale. It determines, for example, whether GTK+ uses the right-to-left or left-to-right text direction.
This function is equivalent to pango_language_get_default()
. See
that function for details.
Returns : |
the default language as a PangoLanguage, must not be freed |
gboolean gtk_parse_args (int *argc
,char ***argv
);
Parses command line arguments, and initializes global
attributes of GTK+, but does not actually open a connection
to a display. (See gdk_display_open()
, gdk_get_display_arg_name()
)
Any arguments used by GTK+ or GDK are removed from the array and
argc
and argv
are updated accordingly.
You shouldn't call this function explicitely if you are using
gtk_init()
, or gtk_init_check()
.
void gtk_init (int *argc
,char ***argv
);
Call this function before using any other GTK+ functions in your GUI
applications. It will initialize everything needed to operate the
toolkit and parses some standard command line options. argc
and
argv
are adjusted accordingly so your own code will
never see those standard arguments.
Note that there are some alternative ways to initialize GTK+:
if you are calling gtk_parse_args()
, gtk_init_check()
,
gtk_init_with_args()
or g_option_context_parse()
with
the option group returned by gtk_get_option_group()
, you
don't have to call gtk_init()
.
This function will terminate your program if it was unable to initialize
the GUI for some reason. If you want your program to fall back to a
textual interface you want to call gtk_init_check()
instead.
Since 2.18, GTK+ calls signal (SIGPIPE, SIG_IGN)
during initialization, to ignore SIGPIPE signals, since these are
almost never wanted in graphical applications. If you do need to
handle SIGPIPE for some reason, reset the handler after gtk_init()
,
but notice that other libraries (e.g. libdbus or gvfs) might do
similar things.
|
Address of the argc parameter of your
main() function. Changed if any arguments were handled. [inout]
|
|
Address of the argv parameter of main() .
Any parameters understood by gtk_init() are stripped before return. [array length=argc][inout length=argc][allow-none length=argc]
|
gboolean gtk_init_check (int *argc
,char ***argv
);
This function does the same work as gtk_init()
with only
a single change: It does not terminate the program if the GUI can't be
initialized. Instead it returns FALSE
on failure.
This way the application can fall back to some other means of communication with the user - for example a curses or command line interface.
|
Address of the argc parameter of your
main() function. Changed if any arguments were handled. [inout]
|
|
Address of the argv parameter of main() .
Any parameters understood by gtk_init() are stripped before return. [array length=argc][inout length=argc][allow-none length=argc]
|
Returns : |
TRUE if the GUI has been successfully initialized,
FALSE otherwise.
|
gboolean gtk_init_with_args (gint *argc
,gchar ***argv
,const gchar *parameter_string
,const GOptionEntry *entries
,const gchar *translation_domain
,GError **error
);
This function does the same work as gtk_init_check()
.
Additionally, it allows you to add your own commandline options,
and it automatically generates nicely formatted
--help
output. Note that your program will
be terminated after writing out the help output.
|
a pointer to the number of command line arguments. |
|
a pointer to the array of command line arguments. |
|
a string which is displayed in
the first line of --help output, after
|
|
a NULL -terminated array of GOptionEntrys
describing the options of your program
|
|
a translation domain to use for translating
the --help output for the options in entries
and the parameter_string with gettext() , or NULL
|
|
a return location for errors |
Returns : |
TRUE if the GUI has been successfully initialized,
FALSE otherwise.
|
Since 2.6
GOptionGroup * gtk_get_option_group (gboolean open_default_display
);
Returns a GOptionGroup for the commandline arguments recognized
by GTK+ and GDK. You should add this group to your GOptionContext
with g_option_context_add_group()
, if you are using
g_option_context_parse()
to parse your commandline arguments.
|
whether to open the default display when parsing the commandline arguments |
Returns : |
a GOptionGroup for the commandline arguments recognized by GTK+ |
Since 2.6
gboolean gtk_events_pending (void
);
Checks if any events are pending. This can be used to update the GUI and invoke timeouts etc. while doing some time intensive computation.
Example 3. Updating the GUI during a long computation.
1 2 3 4 5 6 |
/* computation going on */ ... while (gtk_events_pending ()) gtk_main_iteration (); ... /* computation continued */ |
void gtk_main (void
);
Runs the main loop until gtk_main_quit()
is called. You can nest calls to
gtk_main()
. In that case gtk_main_quit()
will make the innermost invocation
of the main loop return.
guint gtk_main_level (void
);
Asks for the current nesting level of the main loop. This can be useful
when calling gtk_quit_add()
.
Returns : |
the nesting level of the current invocation of the main loop. |
void gtk_main_quit (void
);
Makes the innermost invocation of the main loop return when it regains control.
gboolean gtk_main_iteration (void
);
Runs a single iteration of the mainloop. If no events are waiting to be
processed GTK+ will block until the next event is noticed. If you don't
want to block look at gtk_main_iteration_do()
or check if any events are
pending with gtk_events_pending()
first.
Returns : |
TRUE if gtk_main_quit() has been called for the innermost mainloop.
|
gboolean gtk_main_iteration_do (gboolean blocking
);
Runs a single iteration of the mainloop. If no events are available either
return or block dependent on the value of blocking
.
|
TRUE if you want GTK+ to block if no events are pending.
|
Returns : |
TRUE if gtk_main_quit() has been called for the innermost mainloop.
|
void gtk_main_do_event (GdkEvent *event
);
Processes a single GDK event. This is public only to allow filtering of events between GDK and GTK+. You will not usually need to call this function directly.
While you should not call this function directly, you might want to know how exactly events are handled. So here is what this function does with the event:
Compress enter/leave notify events. If the event passed build an enter/leave pair together with the next event (peeked from GDK) both events are thrown away. This is to avoid a backlog of (de-)highlighting widgets crossed by the pointer.
Find the widget which got the event. If the widget can't be determined
the event is thrown away unless it belongs to a INCR transaction. In that
case it is passed to gtk_selection_incr_event()
.
Then the event is passed on a stack so you can query the currently handled
event with gtk_get_current_event()
.
The event is sent to a widget. If a grab is active all events for widgets that are not in the contained in the grab widget are sent to the latter with a few exceptions:
Deletion and destruction events are still sent to the event widget for obvious reasons.
Events which directly relate to the visual representation of the event widget.
Leave events are delivered to the event widget if there was an enter event delivered to it before without the paired leave event.
Drag events are not redirected because it is unclear what the semantics of that would be.
Another point of interest might be that all key events are first passed
through the key snooper functions if there are any. Read the description
of gtk_key_snooper_install()
if you need this feature.
After finishing the delivery the event is popped from the event stack.
|
An event to process (normally) passed by GDK. |
void (*GtkModuleInitFunc) (gint *argc
,gchar ***argv
);
Each GTK+ module must have a function gtk_module_init()
with this prototype.
This function is called after loading the module with the argc
and argv
cleaned from any arguments that GTK+ handles itself.
|
Pointer to the number of arguments remaining after gtk_init() .
|
|
Points to the argument vector. |
void (*GtkModuleDisplayInitFunc) (GdkDisplay *display
);
|
Since 2.2
gboolean gtk_true (void
);
All this function does it to return TRUE
. This can be useful for example
if you want to inhibit the deletion of a window. Of course you should
not do this as the user expects a reaction from clicking the close
icon of the window...
Example 4. A persistent window
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 |
##include <gtk/gtk.h> int main (int argc, char **argv) { GtkWidget *win, *but; gtk_init( &argc, &argv ); win = gtk_window_new (GTK_WINDOW_TOPLEVEL); g_signal_connect (win, "delete-event", G_CALLBACK (gtk_true), NULL); g_signal_connect (win, "destroy", G_CALLBACK (gtk_main_quit), NULL); but = gtk_button_new_with_label ("Close yourself. I mean it!"); g_signal_connect_swapped (but, "clicked", G_CALLBACK (gtk_object_destroy), win); gtk_container_add (GTK_CONTAINER (win), but); gtk_widget_show_all (win); gtk_main (); return 0; } |
Returns : |
TRUE
|
gboolean gtk_false (void
);
Analogical to gtk_true()
this function does nothing
but always returns FALSE
.
Returns : |
FALSE
|
void gtk_grab_add (GtkWidget *widget
);
Makes widget
the current grabbed widget. This means that interaction with
other widgets in the same application is blocked and mouse as well as
keyboard events are delivered to this widget.
If widget
is not sensitive, it is not set as the current grabbed
widget and this function does nothing.
|
The widget that grabs keyboard and pointer events. |
GtkWidget* gtk_grab_get_current (void
);
Queries the current grab of the default window group.
Returns : |
The widget which currently
has the grab or NULL if no grab is active. [transfer none]
|
void gtk_grab_remove (GtkWidget *widget
);
Removes the grab from the given widget. You have to pair calls to gtk_grab_add()
and gtk_grab_remove()
.
If widget
does not have the grab, this function does nothing.
|
The widget which gives up the grab. |
void gtk_device_grab_add (GtkWidget *widget
,GdkDevice *device
,gboolean block_others
);
Adds a GTK+ grab on device
, so all the events on device
and its
associated pointer or keyboard (if any) are delivered to widget
.
If the block_others
parameter is TRUE
, any other devices will be
unable to interact with widget
during the grab.
|
a GtkWidget |
|
a GtkDevice to grab on. |
|
TRUE to prevent other devices to interact with widget .
|
Since 3.0
void gtk_device_grab_remove (GtkWidget *widget
,GdkDevice *device
);
Removes a device grab from the given widget. You have to pair calls
to gtk_device_grab_add()
and gtk_device_grab_remove()
.
Since 3.0
void gtk_init_add (GtkFunction function
,gpointer data
);
Registers a function to be called when the mainloop is started.
|
Function to invoke when gtk_main() is called next.
|
|
Data to pass to that function. |
void gtk_quit_add_destroy (guint main_level
,GtkWidget *object
);
Trigger destruction of object
in case the mainloop at level main_level
is quit.
|
Level of the mainloop which shall trigger the destruction. |
|
Object to be destroyed. |
guint gtk_quit_add (guint main_level
,GtkFunction function
,gpointer data
);
Registers a function to be called when an instance of the mainloop is left.
|
Level at which termination the function shall be called. You can pass 0 here to have the function run at the termination of the current mainloop. |
|
The function to call. This should return 0 to be removed from the list of quit handlers. Otherwise the function might be called again. |
|
Pointer to pass when calling function .
|
Returns : |
A handle for this quit handler (you need this for gtk_quit_remove() )
or 0 if you passed a NULL pointer in function .
|
void (*GtkCallbackMarshal) (GObject *object
,gpointer data
,guint n_args
,GtkArg *args
);
Defines a function pointer.
typedef struct { GType type; gchar *name; /* this union only defines the required storage types for * the possibile values, thus there is no gint enum_data field, * because that would just be a mere alias for gint int_data. * use the GTK_VALUE_*() and GTK_RETLOC_*() macros to access * the discrete memebers. */ union { /* flat values */ gchar char_data; guchar uchar_data; gboolean bool_data; gint int_data; guint uint_data; glong long_data; gulong ulong_data; gfloat float_data; gdouble double_data; gchar *string_data; GObject *object_data; gpointer pointer_data; /* structured values */ struct { GCallback f; gpointer d; } signal_data; } d; } GtkArg;
This is a structure that we use to pass in typed values (and names).
guint gtk_quit_add_full (guint main_level
,GtkFunction function
,GtkCallbackMarshal marshal
,gpointer data
,GDestroyNotify destroy
);
Registers a function to be called when an instance of the mainloop is left.
In comparison to gtk_quit_add()
this function adds the possibility to
pass a marshaller and a function to be called when the quit handler is freed.
The former can be used to run interpreted code instead of a compiled function
while the latter can be used to free the information stored in data
(while
you can do this in function
as well)... So this function will mostly be
used by GTK+ wrappers for languages other than C.
|
Level at which termination the function shall be called. You can pass 0 here to have the function run at the termination of the current mainloop. |
|
The function to call. This should return 0 to be removed from the list of quit handlers. Otherwise the function might be called again. |
|
The marshaller to be used. If this is non-NULL , function is
ignored.
|
|
Pointer to pass when calling function .
|
|
Function to call to destruct data . Gets data as argument.
|
Returns : |
A handle for this quit handler (you need this for gtk_quit_remove() )
or 0 if you passed a NULL pointer in function .
|
void gtk_quit_remove (guint quit_handler_id
);
Removes a quit handler by its identifier.
|
Identifier for the handler returned when installing it. |
void gtk_quit_remove_by_data (gpointer data
);
Removes a quit handler identified by its data
field.
|
The pointer passed as data to gtk_quit_add() or gtk_quit_add_full() .
|
#define GTK_PRIORITY_RESIZE (G_PRIORITY_HIGH_IDLE + 10)
Use this priority for resizing related stuff. It is used internally by
GTK+ to compute the sizes of widgets. This priority is higher than
GDK_PRIORITY_REDRAW
to avoid resizing a widget which was just redrawn.
guint gtk_key_snooper_install (GtkKeySnoopFunc snooper
,gpointer func_data
);
Installs a key snooper function, which will get called on all key events before delivering them normally.
|
a GtkKeySnoopFunc. |
|
data to pass to snooper .
|
Returns : |
a unique id for this key snooper for use with gtk_key_snooper_remove() .
|
gint (*GtkKeySnoopFunc) (GtkWidget *grab_widget
,GdkEventKey *event
,gpointer func_data
);
Key snooper functions are called before normal event delivery. They can be used to implement custom key event handling.
|
the widget to which the event will be delivered. |
|
the key event. |
|
the func_data supplied to gtk_key_snooper_install() .
|
Returns : |
TRUE to stop further processing of event , FALSE to continue.
|
void gtk_key_snooper_remove (guint snooper_handler_id
);
Removes the key snooper function with the given id.
|
Identifies the key snooper to remove. |
GdkEvent* gtk_get_current_event (void
);
Obtains a copy of the event currently being processed by GTK+. For
example, if you get a "clicked" signal from GtkButton, the current
event will be the GdkEventButton that triggered the "clicked"
signal. The returned event must be freed with gdk_event_free()
.
If there is no current event, the function returns NULL
.
Returns : |
a copy of the current event, or NULL if no current event.
|
guint32 gtk_get_current_event_time (void
);
If there is a current event and it has a timestamp, return that
timestamp, otherwise return GDK_CURRENT_TIME
.
Returns : |
the timestamp from the current event, or GDK_CURRENT_TIME .
|
gboolean gtk_get_current_event_state (GdkModifierType *state
);
If there is a current event and it has a state field, place
that state field in state
and return TRUE
, otherwise return
FALSE
.
|
a location to store the state of the current event |
Returns : |
TRUE if there was a current event and it had a state field
|
GdkDevice * gtk_get_current_event_device (void
);
If there is a current event and it has a device, return that
device, otherwise return NULL
.
GtkWidget* gtk_get_event_widget (GdkEvent *event
);
If event
is NULL
or the event was not associated with any widget,
returns NULL
, otherwise returns the widget that received the event
originally.
void gtk_propagate_event (GtkWidget *widget
,GdkEvent *event
);
Sends an event to a widget, propagating the event to parent widgets
if the event remains unhandled. Events received by GTK+ from GDK
normally begin in gtk_main_do_event()
. Depending on the type of
event, existence of modal dialogs, grabs, etc., the event may be
propagated; if so, this function is used. gtk_propagate_event()
calls gtk_widget_event()
on each widget it decides to send the
event to. So gtk_widget_event()
is the lowest-level function; it
simply emits the "event" and possibly an event-specific signal on a
widget. gtk_propagate_event()
is a bit higher-level, and
gtk_main_do_event()
is the highest level.
All that said, you most likely don't want to use any of these
functions; synthesizing events is rarely needed. Consider asking on
the mailing list for better ways to achieve your goals. For
example, use gdk_window_invalidate_rect()
or
gtk_widget_queue_draw()
instead of making up expose events.
|
a GtkWidget |
|
an event |
See the GLib manual, especially GMainLoop and signal-related
functions such as g_signal_connect()
.