Class: Gtk::Clipboard

Inherits:
Object
  • Object
show all
Defined in:
(unknown)

Overview

The Gtk::Clipboard 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 Gdk::Atom. (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+.)

Instance Method Summary collapse

Instance Method Details

#clearnil

Clears the contents of the clipboard. Generally this should only be called between the time you call gtk_clipboard_set_with_owner() or gtk_clipboard_set_with_data(), and when the clear_func you supplied is called. Otherwise, the clipboard may be owned by someone else.

Returns:

  • (nil)

#displayGdk::Display

Gets the Gdk::Display associated with clipboard

Returns:

  • (Gdk::Display)

    the Gdk::Display associated with clipboard

#image=(pixbuf) ⇒ nil

Sets the contents of the clipboard to the given Gdk::Pixbuf. GTK+ will take responsibility for responding for requests for the image, and for converting the image into the requested format.

Parameters:

Returns:

  • (nil)

#ownerGObject::Object

If the clipboard contents callbacks were set with gtk_clipboard_set_with_owner(), and the gtk_clipboard_set_with_data() or gtk_clipboard_clear() has not subsequently called, returns the owner set by gtk_clipboard_set_with_owner().

Returns:

  • (GObject::Object)

    the owner of the clipboard, if any; otherwise nil.

#request_contents(target, callback, user_data) ⇒ nil

Requests the contents of clipboard as the given target. When the results of the result are later received the supplied callback will be called.

Parameters:

  • target (Gdk::Atom)

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

  • callback (Gtk::ClipboardReceivedFunc)

    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.

  • user_data (GObject)

    user data to pass to callback

Returns:

  • (nil)

#request_image(callback, user_data) ⇒ nil

Requests the contents of the clipboard as image. When the image is later received, it will be converted to a Gdk::Pixbuf, and callback will be called.

The pixbuf parameter to callback will contain the resulting Gdk::Pixbuf if the request succeeded, or nil if it 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 an image.

Parameters:

  • callback (Gtk::ClipboardImageReceivedFunc)

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

  • user_data (GObject)

    user data to pass to callback.

Returns:

  • (nil)

#request_rich_text(buffer, callback, user_data) ⇒ nil

Requests the contents of the clipboard as rich text. When the rich text is later received, callback will be called.

The text parameter to callback will contain the resulting rich text if the request succeeded, or nil if it failed. The length parameter will contain text’s length. This function can fail for various reasons, in particular if the clipboard was empty or if the contents of the clipboard could not be converted into rich text form.

Parameters:

  • buffer (Gtk::TextBuffer)

    a Gtk::TextBuffer

  • callback (Gtk::ClipboardRichTextReceivedFunc)

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

  • user_data (GObject)

    user data to pass to callback.

Returns:

  • (nil)

#request_targets(callback, user_data) ⇒ nil

Requests the contents of the clipboard as list of supported targets. When the list is later received, callback will be called.

The targets parameter to callback will contain the resulting targets if the request succeeded, or nil if it failed.

Parameters:

  • callback (Gtk::ClipboardTargetsReceivedFunc)

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

  • user_data (GObject)

    user data to pass to callback.

Returns:

  • (nil)

#request_text(callback, user_data) ⇒ nil

Requests the contents of the clipboard as text. When the text is later received, it will be converted to UTF-8 if necessary, and callback will be called.

The text parameter to callback will contain the resulting text if the request succeeded, or nil if it 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.

Parameters:

  • callback (Gtk::ClipboardTextReceivedFunc)

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

  • user_data (GObject)

    user data to pass to callback.

Returns:

  • (nil)

#request_uris(callback, user_data) ⇒ nil

Requests the contents of the clipboard as URIs. When the URIs are later received callback will be called.

The uris parameter to callback will contain the resulting array of URIs if the request succeeded, or nil if it 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 URI form.

Parameters:

  • callback (Gtk::ClipboardURIReceivedFunc)

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

  • user_data (GObject)

    user data to pass to callback.

Returns:

  • (nil)

#selectionGdk::Atom

Gets the selection that this clipboard is for.

Returns:

  • (Gdk::Atom)

    the selection

#set_can_store(targets, n_targets) ⇒ nil

Hints that the clipboard data should be stored somewhere when the application exits or when gtk_clipboard_store () is called.

This value is reset when the clipboard owner changes. Where the clipboard data is stored is platform dependent, see gdk_display_store_clipboard () for more information.

Parameters:

  • targets (Array<Gtk::TargetEntry>)

    array containing information about which forms should be stored or nil to indicate that all forms should be stored.

  • n_targets (Integer)

    number of elements in targets

Returns:

  • (nil)

#set_text(text, len) ⇒ nil

Sets the contents of the clipboard to the given UTF-8 string. GTK+ will make a copy of the text and take responsibility for responding for requests for the text, and for converting the text into the requested format.

Parameters:

  • text (String)

    a UTF-8 string.

  • len (Integer)

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

Returns:

  • (nil)

#set_with_data(targets, n_targets, get_func, clear_func, user_data) ⇒ TrueClass

Virtually sets the contents of the specified clipboard by providing a list of supported formats for the clipboard data and a function to call to get the actual data when it is requested.

Parameters:

  • targets (Array<Gtk::TargetEntry>)

    array containing information about the available forms for the clipboard data

  • n_targets (Integer)

    number of elements in targets

  • get_func (Gtk::ClipboardGetFunc)

    function to call to get the actual clipboard data

  • clear_func (Gtk::ClipboardClearFunc)

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

  • user_data (GObject)

    user data to pass to get_func and clear_func.

Returns:

  • (TrueClass)

    true if setting the clipboard data succeeded. If setting the clipboard data failed the provided callback functions will be ignored.

#set_with_owner(targets, n_targets, get_func, clear_func, owner) ⇒ TrueClass

Virtually sets the contents of the specified clipboard by providing a list of supported formats for the clipboard data and a function to call to get the actual data when it is requested.

The difference between this function and gtk_clipboard_set_with_data() is that instead of an generic user_data pointer, a #GObject is passed in.

Parameters:

  • targets (Array<Gtk::TargetEntry>)

    array containing information about the available forms for the clipboard data

  • n_targets (Integer)

    number of elements in targets

  • get_func (Gtk::ClipboardGetFunc)

    function to call to get the actual clipboard data

  • clear_func (Gtk::ClipboardClearFunc)

    when the clipboard contents are set again, this function will be called, and get_func will not be subsequently called

  • owner (GObject::Object)

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

Returns:

  • (TrueClass)

    true if setting the clipboard data succeeded. If setting the clipboard data failed the provided callback functions will be ignored.

#storenil

Stores the current clipboard data somewhere so that it will stay around after the application has quit.

Returns:

  • (nil)

#wait_for_contents(target) ⇒ Gtk::SelectionData

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

Parameters:

  • target (Gdk::Atom)

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

Returns:

  • (Gtk::SelectionData)

    a newly-allocated Gtk::SelectionData object or nil if retrieving the given target failed. If non-nil, this value must be freed with gtk_selection_data_free() when you are finished with it.

#wait_for_imageGdkPixbuf::Pixbuf

Requests the contents of the clipboard as image and converts the result to a Gdk::Pixbuf. This function waits for the data to be received using the main loop, so events, timeouts, etc, may be dispatched during the wait.

Returns:

  • (GdkPixbuf::Pixbuf)

    a newly-allocated Gdk::Pixbuf object which must be disposed with g_object_unref(), or nil 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 an image.)

#wait_for_rich_text(buffer, format, length) ⇒ Array<Integer>

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.

Parameters:

  • buffer (Gtk::TextBuffer)

    a Gtk::TextBuffer

  • format (Gdk::Atom)

    return location for the format of the returned data

  • length (Integer)

    return location for the length of the returned data

Returns:

  • (Array<Integer>)

    a newly-allocated binary block of data which must be freed with g_free(), or nil 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.)

#wait_for_targets(targets, n_targets) ⇒ TrueClass

Returns a list of targets that are present on the clipboard, or nil if there aren’t any targets available. The returned list must be freed with g_free(). This function waits for the data to be received using the main loop, so events, timeouts, etc, may be dispatched during the wait.

Parameters:

  • targets (Array<Gdk::Atom>)

    location to store an array of targets. The result stored here must be freed with g_free().

  • n_targets (Integer)

    location to store number of items in targets.

Returns:

  • (TrueClass)

    true if any targets are present on the clipboard, otherwise false.

#wait_for_textString

Requests the contents of the clipboard as text and converts the result to UTF-8 if necessary. This function waits for the data to be received using the main loop, so events, timeouts, etc, may be dispatched during the wait.

Returns:

  • (String)

    a newly-allocated UTF-8 string which must be freed with g_free(), or nil 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.)

#wait_for_urisArray<String>

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

Returns:

  • (Array<String>)

    a newly-allocated nil-terminated array of strings which must be freed with g_strfreev(), or nil 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 URI form.)

#wait_is_image_availableTrueClass

Test to see if there is an image available to be pasted This is done by requesting the TARGETS atom and checking if it contains any of the supported image targets. This function waits for the data to be received using the main loop, so events, timeouts, etc, may be dispatched during the wait.

This function is a little faster than calling gtk_clipboard_wait_for_image() since it doesn’t need to retrieve the actual image data.

Returns:

  • (TrueClass)

    true is there is an image available, false otherwise.

#wait_is_rich_text_available(buffer) ⇒ TrueClass

Test to see if there is rich text available to be pasted This is done by requesting the TARGETS atom and checking if it contains any of the supported rich text targets. This function waits for the data to be received using the main loop, so events, timeouts, etc, may be dispatched during the wait.

This function is a little faster than calling gtk_clipboard_wait_for_rich_text() since it doesn’t need to retrieve the actual text.

Parameters:

Returns:

  • (TrueClass)

    true is there is rich text available, false otherwise.

#wait_is_target_available(target) ⇒ TrueClass

Checks if a clipboard supports pasting data of a given type. This function can be used to determine if a “Paste” menu item should be insensitive or not.

If you want to see if there’s text available on the clipboard, use gtk_clipboard_wait_is_text_available () instead.

Parameters:

  • target (Gdk::Atom)

    A Gdk::Atom indicating which target to look for.

Returns:

  • (TrueClass)

    true if the target is available, false otherwise.

#wait_is_text_availableTrueClass

Test to see if there is text available to be pasted This is done by requesting the TARGETS atom and checking if it contains any of the supported text targets. This function waits for the data to be received using the main loop, so events, timeouts, etc, may be dispatched during the wait.

This function is a little faster than calling gtk_clipboard_wait_for_text() since it doesn’t need to retrieve the actual text.

Returns:

  • (TrueClass)

    true is there is text available, false otherwise.

#wait_is_uris_availableTrueClass

Test to see if there is a list of URIs available to be pasted This is done by requesting the TARGETS atom and checking if it contains the URI targets. This function waits for the data to be received using the main loop, so events, timeouts, etc, may be dispatched during the wait.

This function is a little faster than calling gtk_clipboard_wait_for_uris() since it doesn’t need to retrieve the actual URI data.

Returns:

  • (TrueClass)

    true is there is an URI list available, false otherwise.