clipboard(3tk) Tk Built-In Commands clipboard(3tk)
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NAME
clipboard - Manipulate Tk clipboard
SYNOPSIS
clipboard option ?arg arg ...?
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DESCRIPTION
This command provides a Tcl interface to the Tk clipboard, which stores
data for later retrieval using the selection mechanism (via the -selec-
tion CLIPBOARD option). 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 append ?-displayof window? ?-format format? ?-type type? ?--?
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 In-
ter-Client Communication Conventions Manual for complete de-
tails. Type defaults to STRING.
The format argument specifies the representation that should be
used to transmit the selection to the requester (the second col-
umn of Table 2 of the ICCCM), and defaults to STRING. If format
is STRING, the selection is transmitted as 8-bit ASCII charac-
ters. 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 clip-
board requesters that do not use Tk. If the Tk toolkit is being
used to retrieve the CLIPBOARD selection then the value is con-
verted back to a string at the requesting end, so format is ir-
relevant.
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 -.
clipboard clear ?-displayof window?
Claims ownership of the clipboard on window's display and re-
moves any previous contents. Window defaults to “.”. Returns
an empty string.
clipboard get ?-displayof window? ?-type type?
Retrieve data from the clipboard on window's display. Window
defaults to “.”. Type specifies the form in which the data is
to be returned and should be an atom name such as STRING or
FILE_NAME. Type defaults to STRING. This command is equivalent
to “selection get -selection CLIPBOARD”.
Note that on modern X11 systems, the most useful type to re-
trieve for transferred strings is not STRING, but rather
UTF8_STRING.
EXAMPLES
Get the current contents of the clipboard.
if {[catch {clipboard get} contents]} {
# There were no clipboard contents at all
}
Set the clipboard to contain a fixed string.
clipboard clear
clipboard append "some fixed string"
You can put custom data into the clipboard by using a custom -type op-
tion. This is not necessarily portable, but can be very useful. The
method of passing Tcl scripts this way is effective, but should be
mixed with safe interpreters in production code.
# This is a very simple canvas serializer;
# it produces a script that recreates the item(s) when executed
proc getItemConfig {canvas tag} {
set script {}
foreach item [$canvas find withtag $tag] {
append script {$canvas create } [$canvas type $item]
append script { } [$canvas coords $item] { }
foreach config [$canvas itemconf $item] {
lassign $config name - - - value
append script [list $name $value] { }
}
append script \n
}
return [string trim $script]
}
# Set up a binding on a canvas to cut and paste an item
set c [canvas .c]
pack $c
$c create text 150 30 -text "cut and paste me"
bind $c <<Cut>> {
clipboard clear
clipboard append -type TkCanvasItem \
[getItemConfig %W current]
# Delete because this is cut, not copy.
%W delete current
}
bind $c <<Paste>> {
catch {
set canvas %W
eval [clipboard get -type TkCanvasItem]
}
}
SEE ALSO
interp(3tcl), selection(3tk)
KEYWORDS
clear, format, clipboard, append, selection, type
Tk 8.4 clipboard(3tk)
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