This command provides a Tcl interface to the Tk clipboard,
which stores data for later retrieval using the selection mechanism.
In order to copy data into the clipboard, clipboard clear must
be called, followed by a sequence of one or more calls to clipboard
append. To ensure that the clipboard is updated atomically, all
appends should be completed before returning to the event loop.
The first argument to clipboard determines the format of the
rest of the arguments and the behavior of the command. The following
forms are currently supported:
clipboard clear ?-displayofwindow?
Claims ownership of the clipboard on window's display and removes
any previous contents. Window defaults to ``.''. Returns an
empty string.
clipboard append ?-displayofwindow? ?-formatformat? ?-typetype? ?--? data
Appends data to the clipboard on window's
display in the form given by type with the representation given
by format and claims ownership of the clipboard on window's
display.
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 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. If
format is ATOM, then the data 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, data 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. Note that strings passed to
clipboard append are concatenated before conversion, so the
caller must take care to ensure appropriate spacing across string
boundaries. All items appended to the clipboard with the same
type must have the same format.
The format argument is needed only for compatibility with
clipboard requesters that don't use Tk. If the Tk toolkit is being
used to retrieve the CLIPBOARD selection then the value is converted back to
a string at the requesting end, so format is
irrelevant.
A -- argument may be specified to mark the end of options: the
next argument will always be used as data.
This feature may be convenient if, for example, data starts
with a -.