Clipboards

Clipboards — Storing data on clipboards

Synopsis

#include <gtk/gtk.h>

                    GtkClipboard;
void                (*GtkClipboardReceivedFunc)         (GtkClipboard *clipboard,
                                                         GtkSelectionData *selection_data,
                                                         gpointer data);
void                (*GtkClipboardTextReceivedFunc)     (GtkClipboard *clipboard,
                                                         const gchar *text,
                                                         gpointer data);
void                (*GtkClipboardImageReceivedFunc)    (GtkClipboard *clipboard,
                                                         GdkPixbuf *pixbuf,
                                                         gpointer data);
void                (*GtkClipboardTargetsReceivedFunc)  (GtkClipboard *clipboard,
                                                         GdkAtom *atoms,
                                                         gint n_atoms,
                                                         gpointer data);
void                (*GtkClipboardRichTextReceivedFunc) (GtkClipboard *clipboard,
                                                         GdkAtom format,
                                                         const guint8 *text,
                                                         gsize length,
                                                         gpointer data);
void                (*GtkClipboardURIReceivedFunc)      (GtkClipboard *clipboard,
                                                         gchar **uris,
                                                         gpointer data);
void                (*GtkClipboardGetFunc)              (GtkClipboard *clipboard,
                                                         GtkSelectionData *selection_data,
                                                         guint info,
                                                         gpointer user_data_or_owner);
void                (*GtkClipboardClearFunc)            (GtkClipboard *clipboard,
                                                         gpointer user_data_or_owner);
GtkClipboard *      gtk_clipboard_get                   (GdkAtom selection);
GtkClipboard *      gtk_clipboard_get_for_display       (GdkDisplay *display,
                                                         GdkAtom selection);
GdkDisplay *        gtk_clipboard_get_display           (GtkClipboard *clipboard);
gboolean            gtk_clipboard_set_with_data         (GtkClipboard *clipboard,
                                                         const GtkTargetEntry *targets,
                                                         guint n_targets,
                                                         GtkClipboardGetFunc get_func,
                                                         GtkClipboardClearFunc clear_func,
                                                         gpointer user_data);
gboolean            gtk_clipboard_set_with_owner        (GtkClipboard *clipboard,
                                                         const GtkTargetEntry *targets,
                                                         guint n_targets,
                                                         GtkClipboardGetFunc get_func,
                                                         GtkClipboardClearFunc clear_func,
                                                         GObject *owner);
GObject *           gtk_clipboard_get_owner             (GtkClipboard *clipboard);
void                gtk_clipboard_clear                 (GtkClipboard *clipboard);
void                gtk_clipboard_set_text              (GtkClipboard *clipboard,
                                                         const gchar *text,
                                                         gint len);
void                gtk_clipboard_set_image             (GtkClipboard *clipboard,
                                                         GdkPixbuf *pixbuf);
void                gtk_clipboard_request_contents      (GtkClipboard *clipboard,
                                                         GdkAtom target,
                                                         GtkClipboardReceivedFunc callback,
                                                         gpointer user_data);
void                gtk_clipboard_request_text          (GtkClipboard *clipboard,
                                                         GtkClipboardTextReceivedFunc callback,
                                                         gpointer user_data);
void                gtk_clipboard_request_image         (GtkClipboard *clipboard,
                                                         GtkClipboardImageReceivedFunc callback,
                                                         gpointer user_data);
void                gtk_clipboard_request_targets       (GtkClipboard *clipboard,
                                                         GtkClipboardTargetsReceivedFunc callback,
                                                         gpointer user_data);
void                gtk_clipboard_request_rich_text     (GtkClipboard *clipboard,
                                                         GtkTextBuffer *buffer,
                                                         GtkClipboardRichTextReceivedFunc callback,
                                                         gpointer user_data);
void                gtk_clipboard_request_uris          (GtkClipboard *clipboard,
                                                         GtkClipboardURIReceivedFunc callback,
                                                         gpointer user_data);
GtkSelectionData *  gtk_clipboard_wait_for_contents     (GtkClipboard *clipboard,
                                                         GdkAtom target);
gchar *             gtk_clipboard_wait_for_text         (GtkClipboard *clipboard);
GdkPixbuf *         gtk_clipboard_wait_for_image        (GtkClipboard *clipboard);
guint8 *            gtk_clipboard_wait_for_rich_text    (GtkClipboard *clipboard,
                                                         GtkTextBuffer *buffer,
                                                         GdkAtom *format,
                                                         gsize *length);
gchar **            gtk_clipboard_wait_for_uris         (GtkClipboard *clipboard);
gboolean            gtk_clipboard_wait_is_text_available
                                                        (GtkClipboard *clipboard);
gboolean            gtk_clipboard_wait_is_image_available
                                                        (GtkClipboard *clipboard);
gboolean            gtk_clipboard_wait_is_rich_text_available
                                                        (GtkClipboard *clipboard,
                                                         GtkTextBuffer *buffer);
gboolean            gtk_clipboard_wait_is_uris_available
                                                        (GtkClipboard *clipboard);
gboolean            gtk_clipboard_wait_for_targets      (GtkClipboard *clipboard,
                                                         GdkAtom **targets,
                                                         gint *n_targets);
gboolean            gtk_clipboard_wait_is_target_available
                                                        (GtkClipboard *clipboard,
                                                         GdkAtom target);
void                gtk_clipboard_set_can_store         (GtkClipboard *clipboard,
                                                         const GtkTargetEntry *targets,
                                                         gint n_targets);
void                gtk_clipboard_store                 (GtkClipboard *clipboard);

Object Hierarchy

  GObject
   +----GtkClipboard

Signals

  "owner-change"                                   : Run First

Description

The GtkClipboard object represents a clipboard of data shared between different processes or between different widgets in the same process. Each clipboard is identified by a name encoded as a GdkAtom. (Conversion to and from strings can be done with gdk_atom_intern() and gdk_atom_name().) The default clipboard corresponds to the "CLIPBOARD" atom; another commonly used clipboard is the "PRIMARY" clipboard, which, in X, traditionally contains the currently selected text.

To support having a number of different formats on the clipboard at the same time, the clipboard mechanism allows providing callbacks instead of the actual data. When you set the contents of the clipboard, you can either supply the data directly (via functions like gtk_clipboard_set_text()), or you can supply a callback to be called at a later time when the data is needed (via gtk_clipboard_set_with_data() or gtk_clipboard_set_with_owner().) Providing a callback also avoids having to make copies of the data when it is not needed.

gtk_clipboard_set_with_data() and gtk_clipboard_set_with_owner() are quite similar; the choice between the two depends mostly on which is more convenient in a particular situation. The former is most useful when you want to have a blob of data with callbacks to convert it into the various data types that you advertise. When the clear_func you provided is called, you simply free the data blob. The latter is more useful when the contents of clipboard reflect the internal state of a GObject (As an example, for the PRIMARY clipboard, when an entry widget provides the clipboard's contents the contents are simply the text within the selected region.) If the contents change, the entry widget can call gtk_clipboard_set_with_owner() to update the timestamp for clipboard ownership, without having to worry about clear_func being called.

Requesting the data from the clipboard is essentially asynchronous. If the contents of the clipboard are provided within the same process, then a direct function call will be made to retrieve the data, but if they are provided by another process, then the data needs to be retrieved from the other process, which may take some time. To avoid blocking the user interface, the call to request the selection, gtk_clipboard_request_contents() takes a callback that will be called when the contents are received (or when the request fails.) If you don't want to deal with providing a separate callback, you can also use gtk_clipboard_wait_for_contents(). What this does is run the GLib main loop recursively waiting for the contents. This can simplify the code flow, but you still have to be aware that other callbacks in your program can be called while this recursive mainloop is running.

Along with the functions to get the clipboard contents as an arbitrary data chunk, there are also functions to retrieve it as text, gtk_clipboard_request_text() and gtk_clipboard_wait_for_text(). These functions take care of determining which formats are advertised by the clipboard provider, asking for the clipboard in the best available format and converting the results into the UTF-8 encoding. (The standard form for representing strings in GTK+.)

Details

GtkClipboard

typedef struct _GtkClipboard GtkClipboard;

GtkClipboardReceivedFunc ()

void                (*GtkClipboardReceivedFunc)         (GtkClipboard *clipboard,
                                                         GtkSelectionData *selection_data,
                                                         gpointer data);

A function to be called when the results of gtk_clipboard_request_contents() are received, or when the request fails.

clipboard :

the GtkClipboard

selection_data :

a GtkSelectionData containing the data was received. If retrieving the data failed, then then length field of selection_data will be negative.

data :

the user_data supplied to gtk_clipboard_request_contents().

GtkClipboardTextReceivedFunc ()

void                (*GtkClipboardTextReceivedFunc)     (GtkClipboard *clipboard,
                                                         const gchar *text,
                                                         gpointer data);

A function to be called when the results of gtk_clipboard_request_text() are received, or when the request fails.

clipboard :

the GtkClipboard

text :

the text received, as a UTF-8 encoded string, or NULL if retrieving the data failed.

data :

the user_data supplied to gtk_clipboard_request_text().

GtkClipboardImageReceivedFunc ()

void                (*GtkClipboardImageReceivedFunc)    (GtkClipboard *clipboard,
                                                         GdkPixbuf *pixbuf,
                                                         gpointer data);

A function to be called when the results of gtk_clipboard_request_image() are received, or when the request fails.

clipboard :

the GtkClipboard

pixbuf :

the received image

data :

the user_data supplied to gtk_clipboard_request_image().

Since 2.6


GtkClipboardTargetsReceivedFunc ()

void                (*GtkClipboardTargetsReceivedFunc)  (GtkClipboard *clipboard,
                                                         GdkAtom *atoms,
                                                         gint n_atoms,
                                                         gpointer data);

A function to be called when the results of gtk_clipboard_request_targets() are received, or when the request fails.

clipboard :

the GtkClipboard

atoms :

the supported targets, as array of GdkAtom, or NULL if retrieving the data failed.

n_atoms :

the length of the atoms array.

data :

the user_data supplied to gtk_clipboard_request_targets().

Since 2.4


GtkClipboardRichTextReceivedFunc ()

void                (*GtkClipboardRichTextReceivedFunc) (GtkClipboard *clipboard,
                                                         GdkAtom format,
                                                         const guint8 *text,
                                                         gsize length,
                                                         gpointer data);

GtkClipboardURIReceivedFunc ()

void                (*GtkClipboardURIReceivedFunc)      (GtkClipboard *clipboard,
                                                         gchar **uris,
                                                         gpointer data);

GtkClipboardGetFunc ()

void                (*GtkClipboardGetFunc)              (GtkClipboard *clipboard,
                                                         GtkSelectionData *selection_data,
                                                         guint info,
                                                         gpointer user_data_or_owner);

A function that will be called to provide the contents of the selection. If multiple types of data were advertised, the requested type can be determined from the info parameter or by checking the target field of selection_data. If the data could successfully be converted into then it should be stored into the selection_data object by calling gtk_selection_data_set() (or related functions such as gtk_selection_data_set_text()). If no data is set, the requestor will be informed that the attempt to get the data failed.

clipboard :

the GtkClipboard

selection_data :

a GtkSelectionData argument in which the requested data should be stored.

info :

the info field corresponding to the requested target from the GtkTargetEntry array passed to gtk_clipboard_set_with_data() or gtk_clipboard_set_with_owner().

user_data_or_owner :

the user_data argument passed to gtk_clipboard_set_with_data(), or the owner argument passed to gtk_clipboard_set_with_owner()

GtkClipboardClearFunc ()

void                (*GtkClipboardClearFunc)            (GtkClipboard *clipboard,
                                                         gpointer user_data_or_owner);

A function that will be called when the contents of the clipboard are changed or cleared. Once this has called, the user_data_or_owner argument will not be used again.

clipboard :

the GtkClipboard

user_data_or_owner :

the user_data argument passed to gtk_clipboard_set_with_data(), or the owner argument passed to gtk_clipboard_set_with_owner()

gtk_clipboard_get ()

GtkClipboard *      gtk_clipboard_get                   (GdkAtom selection);

selection :

a GdkAtom which identifies the clipboard to use

gtk_clipboard_get_for_display ()

GtkClipboard *      gtk_clipboard_get_for_display       (GdkDisplay *display,
                                                         GdkAtom selection);

display :

the display for which the clipboard is to be retrieved or created

selection :

a GdkAtom which identifies the clipboard to use.

Since 2.2


gtk_clipboard_get_display ()

GdkDisplay *        gtk_clipboard_get_display           (GtkClipboard *clipboard);

clipboard :

a GtkClipboard

Since 2.2


gtk_clipboard_set_with_data ()

gboolean            gtk_clipboard_set_with_data         (GtkClipboard *clipboard,
                                                         const GtkTargetEntry *targets,
                                                         guint n_targets,
                                                         GtkClipboardGetFunc get_func,
                                                         GtkClipboardClearFunc clear_func,
                                                         gpointer user_data);

clipboard :

a GtkClipboard

targets :

array containing information about the available forms for the clipboard data. [array length=n_targets]

n_targets :

number of elements in targets

get_func :

function to call to get the actual clipboard data. [scope async]

clear_func :

when the clipboard contents are set again, this function will be called, and get_func will not be subsequently called. [scope async]

user_data :

user data to pass to get_func and clear_func.

gtk_clipboard_set_with_owner ()

gboolean            gtk_clipboard_set_with_owner        (GtkClipboard *clipboard,
                                                         const GtkTargetEntry *targets,
                                                         guint n_targets,
                                                         GtkClipboardGetFunc get_func,
                                                         GtkClipboardClearFunc clear_func,
                                                         GObject *owner);

clipboard :

a GtkClipboard

targets :

array containing information about the available forms for the clipboard data. [array length=n_targets]

n_targets :

number of elements in targets

get_func :

function to call to get the actual clipboard data. [scope async]

clear_func :

when the clipboard contents are set again, this function will be called, and get_func will not be subsequently called. [scope async]

owner :

an object that "owns" the data. This object will be passed to the callbacks when called

gtk_clipboard_get_owner ()

GObject *           gtk_clipboard_get_owner             (GtkClipboard *clipboard);

clipboard :

a GtkClipboard

gtk_clipboard_clear ()

void                gtk_clipboard_clear                 (GtkClipboard *clipboard);

clipboard :

a GtkClipboard

gtk_clipboard_set_text ()

void                gtk_clipboard_set_text              (GtkClipboard *clipboard,
                                                         const gchar *text,
                                                         gint len);

clipboard :

a GtkClipboard object

text :

a UTF-8 string.

len :

length of text, in bytes, or -1, in which case the length will be determined with strlen().

gtk_clipboard_set_image ()

void                gtk_clipboard_set_image             (GtkClipboard *clipboard,
                                                         GdkPixbuf *pixbuf);

clipboard :

a GtkClipboard object

pixbuf :

a GdkPixbuf

Since 2.6


gtk_clipboard_request_contents ()

void                gtk_clipboard_request_contents      (GtkClipboard *clipboard,
                                                         GdkAtom target,
                                                         GtkClipboardReceivedFunc callback,
                                                         gpointer user_data);

clipboard :

a GtkClipboard

target :

an atom representing the form into which the clipboard owner should convert the selection.

callback :

A function to call when the results are received (or the retrieval fails). If the retrieval fails the length field of selection_data will be negative. [scope async]

user_data :

user data to pass to callback

gtk_clipboard_request_text ()

void                gtk_clipboard_request_text          (GtkClipboard *clipboard,
                                                         GtkClipboardTextReceivedFunc callback,
                                                         gpointer user_data);

clipboard :

a GtkClipboard

callback :

a function to call when the text is received, or the retrieval fails. (It will always be called one way or the other.). [scope async]

user_data :

user data to pass to callback.

gtk_clipboard_request_image ()

void                gtk_clipboard_request_image         (GtkClipboard *clipboard,
                                                         GtkClipboardImageReceivedFunc callback,
                                                         gpointer user_data);

clipboard :

a GtkClipboard

callback :

a function to call when the image is received, or the retrieval fails. (It will always be called one way or the other.). [scope async]

user_data :

user data to pass to callback.

Since 2.6


gtk_clipboard_request_targets ()

void                gtk_clipboard_request_targets       (GtkClipboard *clipboard,
                                                         GtkClipboardTargetsReceivedFunc callback,
                                                         gpointer user_data);

clipboard :

a GtkClipboard

callback :

a function to call when the targets are received, or the retrieval fails. (It will always be called one way or the other.). [scope async]

user_data :

user data to pass to callback.

Since 2.4


gtk_clipboard_request_rich_text ()

void                gtk_clipboard_request_rich_text     (GtkClipboard *clipboard,
                                                         GtkTextBuffer *buffer,
                                                         GtkClipboardRichTextReceivedFunc callback,
                                                         gpointer user_data);

clipboard :

a GtkClipboard

buffer :

a GtkTextBuffer

callback :

a function to call when the text is received, or the retrieval fails. (It will always be called one way or the other.). [scope async]

user_data :

user data to pass to callback.

Since 2.10


gtk_clipboard_request_uris ()

void                gtk_clipboard_request_uris          (GtkClipboard *clipboard,
                                                         GtkClipboardURIReceivedFunc callback,
                                                         gpointer user_data);

clipboard :

a GtkClipboard

callback :

a function to call when the URIs are received, or the retrieval fails. (It will always be called one way or the other.). [scope async]

user_data :

user data to pass to callback.

Since 2.14


gtk_clipboard_wait_for_contents ()

GtkSelectionData *  gtk_clipboard_wait_for_contents     (GtkClipboard *clipboard,
                                                         GdkAtom target);

clipboard :

a GtkClipboard

target :

an atom representing the form into which the clipboard owner should convert the selection.

gtk_clipboard_wait_for_text ()

gchar *             gtk_clipboard_wait_for_text         (GtkClipboard *clipboard);

clipboard :

a GtkClipboard

gtk_clipboard_wait_for_image ()

GdkPixbuf *         gtk_clipboard_wait_for_image        (GtkClipboard *clipboard);

clipboard :

a GtkClipboard

Since 2.6


gtk_clipboard_wait_for_rich_text ()

guint8 *            gtk_clipboard_wait_for_rich_text    (GtkClipboard *clipboard,
                                                         GtkTextBuffer *buffer,
                                                         GdkAtom *format,
                                                         gsize *length);

Requests the contents of the clipboard as rich text. This function waits for the data to be received using the main loop, so events, timeouts, etc, may be dispatched during the wait.

clipboard :

a GtkClipboard

buffer :

a GtkTextBuffer

format :

return location for the format of the returned data. [out]

length :

return location for the length of the returned data

Returns :

a newly-allocated binary block of data which must be freed with g_free(), or NULL if retrieving the selection data failed. (This could happen for various reasons, in particular if the clipboard was empty or if the contents of the clipboard could not be converted into text form.). [array length=length][transfer full]

Since 2.10


gtk_clipboard_wait_for_uris ()

gchar **            gtk_clipboard_wait_for_uris         (GtkClipboard *clipboard);

clipboard :

a GtkClipboard

Since 2.14


gtk_clipboard_wait_is_text_available ()

gboolean            gtk_clipboard_wait_is_text_available
                                                        (GtkClipboard *clipboard);

clipboard :

a GtkClipboard

gtk_clipboard_wait_is_image_available ()

gboolean            gtk_clipboard_wait_is_image_available
                                                        (GtkClipboard *clipboard);

clipboard :

a GtkClipboard

Since 2.6


gtk_clipboard_wait_is_rich_text_available ()

gboolean            gtk_clipboard_wait_is_rich_text_available
                                                        (GtkClipboard *clipboard,
                                                         GtkTextBuffer *buffer);

clipboard :

a GtkClipboard

buffer :

a GtkTextBuffer

Since 2.10


gtk_clipboard_wait_is_uris_available ()

gboolean            gtk_clipboard_wait_is_uris_available
                                                        (GtkClipboard *clipboard);

clipboard :

a GtkClipboard

Since 2.14


gtk_clipboard_wait_for_targets ()

gboolean            gtk_clipboard_wait_for_targets      (GtkClipboard *clipboard,
                                                         GdkAtom **targets,
                                                         gint *n_targets);

clipboard :

a GtkClipboard

targets :

location to store an array of targets. The result stored here must be freed with g_free(). [out][array length=n_targets][transfer container]

n_targets :

location to store number of items in targets.

Since 2.4


gtk_clipboard_wait_is_target_available ()

gboolean            gtk_clipboard_wait_is_target_available
                                                        (GtkClipboard *clipboard,
                                                         GdkAtom target);

clipboard :

a GtkClipboard

target :

A GdkAtom indicating which target to look for.

Since 2.6


gtk_clipboard_set_can_store ()

void                gtk_clipboard_set_can_store         (GtkClipboard *clipboard,
                                                         const GtkTargetEntry *targets,
                                                         gint n_targets);

clipboard :

a GtkClipboard

targets :

array containing information about which forms should be stored or NULL to indicate that all forms should be stored. [allow-none][array length=n_targets]

n_targets :

number of elements in targets

Since 2.6


gtk_clipboard_store ()

void                gtk_clipboard_store                 (GtkClipboard *clipboard);

clipboard :

a GtkClipboard

Since 2.6

Signal Details

The "owner-change" signal

void                user_function                      (GtkClipboard *clipboard,
                                                        GdkEvent     *event,
                                                        gpointer      user_data)      : Run First

The ::owner-change signal is emitted when GTK+ receives an event that indicates that the ownership of the selection associated with clipboard has changed.

clipboard :

the GtkClipboard on which the signal is emitted

event :

the GdkEventOwnerChange event. [type Gdk.EventOwnerChange]

user_data :

user data set when the signal handler was connected.

Since 2.6

See Also

GtkSelection