Clipboards

## 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