'\" '\" Copyright (c) 1990-1994 The Regents of the University of California. '\" Copyright (c) 1994-1996 Sun Microsystems, Inc. '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" '\" RCS: @(#) $Id: selection.n,v 1.1.1.1 2007/07/10 15:05:16 duncan Exp $ '\" .so man.macros .TH selection n 8.1 Tk "Tk Built-In Commands" .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME selection \- Manipulate the X selection .SH SYNOPSIS \fBselection \fIoption\fR ?\fIarg arg ...\fR? .BE .SH DESCRIPTION .PP This command provides a Tcl interface to the X selection mechanism and implements the full selection functionality described in the X Inter-Client Communication Conventions Manual (ICCCM). .PP Note that for management of the CLIPBOARD selection (see below), the \fBclipboard\fR command may also be used. .PP The first argument to \fBselection\fR determines the format of the rest of the arguments and the behavior of the command. The following forms are currently supported: .PP .TP \fBselection clear\fR ?\fB\-displayof\fR \fIwindow\fR? ?\fB\-selection\fR \fIselection\fR? If \fIselection\fR exists anywhere on \fIwindow\fR's display, clear it so that no window owns the selection anymore. \fISelection\fR 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. \fISelection\fR defaults to PRIMARY and \fIwindow\fR defaults to ``.''. Returns an empty string. .TP \fBselection get\fR ?\fB\-displayof\fR \fIwindow\fR? ?\fB\-selection\fR \fIselection\fR? ?\fB\-type\fR \fItype\fR? Retrieves the value of \fIselection\fR from \fIwindow\fR's display and returns it as a result. \fISelection\fR defaults to PRIMARY and \fIwindow\fR defaults to ``.''. \fIType\fR 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. \fIType\fR 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 the selection is returned in a non-string format, such as INTEGER or ATOM, the \fBselection\fR command converts it to string format as a collection of fields separated by spaces: atoms are converted to their textual names, and anything else is converted to hexadecimal integers. .TP \fBselection handle\fR ?\fB\-selection\fR \fIselection\fR? ?\fB\-type\fR \fItype\fR? ?\fB\-format\fR \fIformat\fR? \fIwindow command\fR Creates a handler for selection requests, such that \fIcommand\fR will be executed whenever \fIselection\fR is owned by \fIwindow\fR and someone attempts to retrieve it in the form given by \fItype\fR (e.g. \fItype\fR is specified in the \fBselection get\fR command). \fISelection\fR defaults to PRIMARY, \fItype\fR defaults to STRING, and \fIformat\fR defaults to STRING. If \fIcommand\fR is an empty string then any existing handler for \fIwindow\fR, \fItype\fR, and \fIselection\fR is removed. .RS .PP When \fIselection\fR is requested, \fIwindow\fR is the selection owner, and \fItype\fR is the requested type, \fIcommand\fR will be executed as a Tcl command with two additional numbers appended to it (with space separators). The two additional numbers .VS are \fIoffset\fR and \fImaxChars\fR: \fIoffset\fR specifies a starting character position in the selection and \fImaxChars\fR gives the maximum number of characters to retrieve. The command should return a value consisting of at most \fImaxChars\fR of the selection, starting at position \fIoffset\fR. For very large selections (larger than \fImaxChars\fR) the selection will be retrieved using several invocations of \fIcommand\fR with increasing \fIoffset\fR values. If \fIcommand\fR returns a string whose length is less than \fImaxChars\fR, the return value is assumed to include all of the remainder of the selection; if the length of \fIcommand\fR's result is equal to \fImaxChars\fR then \fIcommand\fR will be invoked again, until it eventually returns a result shorter than \fImaxChars\fR. The value of \fImaxChars\fR will always be relatively large (thousands of characters). .VE .PP If \fIcommand\fR returns an error then the selection retrieval is rejected just as if the selection didn't exist at all. .PP The \fIformat\fR 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 \fIformat\fR is STRING, the selection is transmitted as 8-bit ASCII characters (i.e. just in the form returned by \fIcommand\fR). If \fIformat\fR is ATOM, then the return value from \fIcommand\fR 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 \fIformat\fR, the return value from \fIcommand\fR 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. .PP The \fIformat\fR argument is needed only for compatibility with selection requesters that don't use Tk. If Tk is being used to retrieve the selection then the value is converted back to a string at the requesting end, so \fIformat\fR is irrelevant. .RE .TP \fBselection own\fR ?\fB\-displayof\fR \fIwindow\fR? ?\fB\-selection\fR \fIselection\fR? .TP \fBselection own\fR ?\fB\-command\fR \fIcommand\fR? ?\fB\-selection\fR \fIselection\fR? \fIwindow\fR The first form of \fBselection own\fR returns the path name of the window in this application that owns \fIselection\fR on the display containing \fIwindow\fR, or an empty string if no window in this application owns the selection. \fISelection\fR defaults to PRIMARY and \fIwindow\fR defaults to ``.''. .PP The second form of \fBselection own\fR causes \fIwindow\fR to become the new owner of \fIselection\fR on \fIwindow\fR's display, returning an empty string as result. The existing owner, if any, is notified that it has lost the selection. If \fIcommand\fR is specified, it is a Tcl script to execute when some other window claims ownership of the selection away from \fIwindow\fR. \fISelection\fR defaults to PRIMARY. .SH EXAMPLES On X11 platforms, one of the standard selections available is the SECONDARY selection. Hardly anything uses it, but here is how to read it using Tk: .CS set selContents [\fBselection get\fR \-selection SECONDARY] .CE .PP Many different types of data may be available for a selection; the special type TARGETS allows you to get a list of available types: .CS foreach type [\fBselection get\fR \-type TARGETS] { puts "Selection PRIMARY supports type $type" } .CE .PP To claim the selection, you must first set up a handler to supply the data for the selection. Then you have to claim the selection... .CS # Set up the data handler ready for incoming requests set foo "This is a string with some data in it... blah blah" \fBselection handle\fR \-selection SECONDARY . getData proc getData {offset maxChars} { puts "Retrieving selection starting at $offset" return [string range $::foo $offset [expr {$offset+$maxChars}]] } # Now we grab the selection itself puts "Claiming selection" \fBselection own\fR \-command lost \-selection SECONDARY . proc lost {} { puts "Lost selection" } .CE .SH "SEE ALSO" clipboard(n) .SH KEYWORDS clear, format, handler, ICCCM, own, selection, target, type