selection(3)						User Contributed Perl Documentation					      selection(3)

NAME

       Tk::Selection - Manipulate the X selection

SYNOPSIS

       $widget->SelectionOption?(args)?

DESCRIPTION

       This command provides an interface to the X selection mechanism and implements the full selection functionality described in the X Inter-
       Client Communication Conventions Manual (ICCCM).

       The widget object used to invoke the methods below determines which display is used to access the selection.  In order to avoid conflicts
       with selection methods of widget classes (e.g. Text) this set of methods uses the prefix Selection.  The following methods are currently
       supported:

       $widget->SelectionClear?(-selection=>selection)?
	   If selection exists anywhere on $widget's display, clear it so that no window owns the selection anymore.  Selection specifies the X
	   selection that should be cleared, and should be an atom name such as PRIMARY or CLIPBOARD; see the Inter-Client Communication
	   Conventions Manual for complete details.  Selection defaults to PRIMARY.  Returns an empty string.

       $widget->SelectionGet?(?-selection=>selection?,?-type=>type?)?
	   Retrieves the value of selection from $widget's display and returns it as a result.	Selection defaults to PRIMARY.

	   Type specifies the form in which the selection is to be returned (the desired ``target'' for conversion, in ICCCM terminology), and
	   should be an atom name such as STRING or FILE_NAME; see the Inter-Client Communication Conventions Manual for complete details.  Type
	   defaults to STRING.	The selection owner may choose to return the selection in any of several different representation formats, such as
	   STRING, ATOM, INTEGER, etc. (this format is different than the selection type; see the ICCCM for all the confusing details).

	   If format is not STRING then things get messy, the following description is from the Tcl/Tk man page as yet incompetely translated for
	   the perl version - it is misleading at best.

	   If the selection is returned in a non-string format, such as INTEGER or ATOM, the SelectionGet converts it to a list of perl values:
	   atoms are converted to their textual names, and anything else is converted integers.

	   A goal of the perl port is to provide better handling of different formats than Tcl/Tk does, which should be possible given perl's
	   wider range of ``types''. Although some thought went into this in very early days of perl/Tk what exactly happens is still "not quite
	   right" and subject to change.

       $widget->SelectionHandle(?-selection=>selection?,?-type=>type?,?-format=>format? callback)
	   Creates a handler for selection requests, such that callback will be executed whenever selection is owned by $widget and someone
	   attempts to retrieve it in the form given by type (e.g. type is specified in the selection get command).  Selection defaults to
	   PRIMARY, type defaults to STRING, and format defaults to STRING.  If callback is an empty string then any existing handler for $widget,
	   type, and selection is removed.

	   When selection is requested, $widget is the selection owner, and type is the requested type, callback will be executed with two
	   additional arguments.  The two additional arguments are offset and maxBytes:  offset specifies a starting character position in the
	   selection and maxBytes gives the maximum number of bytes to retrieve.  The command should return a value consisting of at most maxBytes
	   of the selection, starting at position offset.  For very large selections (larger than maxBytes) the selection will be retrieved using
	   several invocations of callback with increasing offset values.  If callback returns a string whose length is less than maxBytes, the
	   return value is assumed to include all of the remainder of the selection;  if the length of callback's result is equal to maxBytes then
	   callback will be invoked again, until it eventually returns a result shorter than maxBytes.	The value of maxBytes will always be
	   relatively large (thousands of bytes).

	   If callback returns an error (e.g. via die) then the selection retrieval is rejected just as if the selection didn't exist at all.

	   The format argument specifies the representation that should be used to transmit the selection to the requester (the second column of
	   Table 2 of the ICCCM), and defaults to STRING.  If format is STRING, the selection is transmitted as 8-bit ASCII characters (i.e.  just
	   in the form returned by command).

	   If format is not STRING then things get messy, the following description is from the Tcl/Tk man page as yet untranslated for the perl
	   version - it is misleading at best.

	   If format is ATOM, then the return value from command is divided into fields separated by white space;  each field is converted to its
	   atom value, and the 32-bit atom value is transmitted instead of the atom name.  For any other format, the return value from command is
	   divided into fields separated by white space and each field is converted to a 32-bit integer;  an array of integers is transmitted to
	   the selection requester.

	   The format argument is needed only for compatibility with many selection requesters, except Tcl/Tk.	If Tcl/Tk is being used to
	   retrieve the selection then the value is converted back to a string at the requesting end, so format is irrelevant.

	   A goal of the perl port is to provide better handling of different formats than Tcl/Tk does, which should be possible given perl's
	   wider range of ``types''. Although some thought went into this in very early days of perl/Tk what exactly happens is still "not quite
	   right" and subject to change.

       $widget->SelectionOwner?(-selection=>selection)?
	   SelectionOwner returns the window in this application that owns selection on the display containing $widget, or an empty string if no
	   window in this application owns the selection.  Selection defaults to PRIMARY.

       $widget->SelectionOwn?(?-command=>callback?,?-selection=>selection?)?
	   SelectionOwn causes $widget to become the new owner of selection on $widget's display, returning an empty string as result. The
	   existing owner, if any, is notified that it has lost the selection.	If callback is specified, it will be executed when some other
	   window claims ownership of the selection away from $widget.	Selection defaults to PRIMARY.

KEYWORDS

       clear, format, handler, ICCCM, own, selection, target, type

perl v5.16.3							    2014-06-10							      selection(3)