Interfacing Raku to Gnome GTK+

Gnome::Gtk3::Editable

Interface for text-editing widgets

Description

The Gnome::Gtk3::Editable interface is an interface which should be implemented by text editing widgets, such as Gnome::Gtk3::Entry and Gnome::Gtk3::SpinButton. It contains functions for generically manipulating an editable widget, a large number of action signals used for key bindings, and several signals that an application can connect to to modify the behavior of a widget.

As an example of the latter usage, by connecting the following handler to insert-text, an application can convert all entry into a widget into uppercase.

Synopsis

Declaration

unit role Gnome::Gtk3::Editable;

Methods

copy-clipboard

Copies the contents of the currently selected content in the editable and puts it on the clipboard.

method copy-clipboard ( )

cut-clipboard

Removes the contents of the currently selected content in the editable and puts it on the clipboard.

method cut-clipboard ( )

delete-selection

Deletes the currently selected text of the editable. This call doesn’t do anything if there is no selected text.

method delete-selection ( )

delete-text

Deletes a sequence of characters. The characters that are deleted are those characters at positions from start-pos up to, but not including end-pos. If end-pos is negative, then the characters deleted are those from start-pos to the end of the text.

Note that the positions are specified in characters, not bytes.

method delete-text ( Int $start_pos, Int $end_pos )

  • Int $start_pos; start position

  • Int $end_pos; end position

get-chars

Retrieves a sequence of characters. The characters that are retrieved are those characters at positions from start-pos up to, but not including end-pos. If end-pos is negative, then the characters retrieved are those characters from start-pos to the end of the text.

Note that positions are specified in characters, not bytes.

Returns: a pointer to the contents of the widget as a string. This string is allocated by the Gnome::Gtk3::Editable implementation and should be freed by the caller.

method get-chars ( Int $start_pos, Int $end_pos --> Str )

  • Int $start_pos; start of text

  • Int $end_pos; end of text

get-editable

Retrieves whether editable is editable. See set-editable().

Returns: True if editable is editable.

method get-editable ( --> Bool )

get-position

Retrieves the current position of the cursor relative to the start of the content of the editable.

Note that this position is in characters, not in bytes.

Returns: the cursor position

method get-position ( --> Int )

get-selection-bounds

Retrieves the selection bound of the editable. start-pos will be filled with the start of the selection and end-pos with end. If no text was selected both will be identical and False will be returned.

Note that positions are specified in characters, not bytes.

Returns: True if an area is selected, False otherwise

method get-selection-bounds ( --> Bool )

  • Int $start_pos; location to store the starting position, or undefined

  • Int $end_pos; location to store the end position, or undefined

insert-text

Inserts new-text-length bytes of new-text into the contents of the widget, at position position.

Note that the position is in characters, not in bytes. The function updates position to point after the newly inserted text.

method insert-text ( Str $new_text, Int $new_text_length )

  • Str $new_text; the text to append

  • Int $new_text_length; the length of the text in bytes, or -1

  • Int $position; location of the position text will be inserted at

paste-clipboard

Pastes the content of the clipboard to the current position of the cursor in the editable.

method paste-clipboard ( )

select-region

Selects a region of text. The characters that are selected are those characters at positions from start-pos up to, but not including end-pos. If end-pos is negative, then the characters selected are those characters from start-pos to the end of the text.

Note that positions are specified in characters, not bytes.

method select-region ( Int $start_pos, Int $end_pos )

  • Int $start_pos; start of region

  • Int $end_pos; end of region

set-editable

Determines if the user can edit the text in the editable widget or not.

method set-editable ( Bool $is_editable )
  • Bool $is_editable; True if the user is allowed to edit the text in the widget

set-position

Sets the cursor position in the editable to the given value.

The cursor is displayed before the character with the given (base 0) index in the contents of the editable. The value must be less than or equal to the number of characters in the editable. A value of -1 indicates that the position should be set after the last character of the editable. Note that position is in characters, not in bytes.

method set-position ( Int $position )
  • Int $position; the position of the cursor

Signals

There are two ways to connect to a signal. The first option you have is to use register-signal() from Gnome::GObject::Object. The second option is to use connect-object() directly from Gnome::GObject::Signal.

First method

The positional arguments of the signal handler are all obligatory as well as their types. The named attributes :$widget and user data are optional.

# handler method
method mouse-event ( GdkEvent $event, :$widget ) { ... }

# connect a signal on window object
my Gnome::Gtk3::Window $w .= new( ... );
$w.register-signal( self, 'mouse-event', 'button-press-event');

Second method

my Gnome::Gtk3::Window $w .= new( ... );
my Callable $handler = sub (
  N-GObject $native, GdkEvent $event, OpaquePointer $data
) {
  ...
}

$w.connect-object( 'button-press-event', $handler);

Also here, the types of positional arguments in the signal handler are important. This is because both methods register-signal() and connect-object() are using the signatures of the handler routines to setup the native call interface.

Supported signals

changed

The changed signal is emitted at the end of a single user-visible operation on the contents of the Gnome::Gtk3::Editable.

E.g., a paste operation that replaces the contents of the selection will cause only one signal emission (even though it is implemented by first deleting the selection, then inserting the new content, and may cause multiple notify::text signals to be emitted).

method handler (
  Int :$_handle_id,
  Gnome::GObject::Object :_widget($editable),
  *%user-options
);
  • $editable; the object which received the signal

delete-text

This signal is emitted when text is deleted from the widget by the user. The default handler for this signal will normally be responsible for deleting the text, so by connecting to this signal and then stopping the signal with g-signal-stop-emission(), it is possible to modify the range of deleted text, or prevent it from being deleted entirely. The start-pos and end-pos parameters are interpreted as for delete-text().

method handler (
  Int $start_pos,
  Int $end_pos,
  Int :$_handle_id,
  Gnome::GObject::Object :_widget($editable),
  *%user-options
);

  • $editable; the object which received the signal

  • $start_pos; the starting position

  • $end_pos; the end position

insert-text

This signal is emitted when text is inserted into the widget by the user. The default handler for this signal will normally be responsible for inserting the text, so by connecting to this signal and then stopping the signal with g-signal-stop-emission(), it is possible to modify the inserted text, or prevent it from being inserted entirely.

method handler (
  Str $new_text,
  Int $new_text_length,
  Unknown type G_TYPE_POINTER $position,
  Int :$_handle_id,
  Gnome::GObject::Object :_widget($editable),
  *%user-options
);

  • $editable; the object which received the signal

  • $new_text; the new text to insert

  • $new_text_length; the length of the new text, in bytes, or -1 if new-text is nul-terminated

  • $position; (inout) (type int): the position, in characters, at which to insert the new text. this is an in-outparameter. After the signal emission is finished, itshould point after the newly inserted text.