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'\"
'\" Copyright (c) 1990 The Regents of the University of California.
'\" Copyright (c) 1994-1998 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: GetAnchor.3,v 1.8 2007/10/26 20:13:22 dgp Exp $
'\"
.so man.macros
.TH Tk_GetAnchorFromObj 3 8.1 Tk "Tk Library Procedures"
.BS
.SH NAME
Tk_GetAnchorFromObj, Tk_GetAnchor, Tk_NameOfAnchor \- translate between strings and anchor positions
.SH SYNOPSIS
.nf
\fB#include <tk.h>\fR
.sp
int
\fBTk_GetAnchorFromObj(\fIinterp, objPtr, anchorPtr\fB)\fR
.sp
int
\fBTk_GetAnchor(\fIinterp, string, anchorPtr\fB)\fR
.sp
const char *
\fBTk_NameOfAnchor(\fIanchor\fB)\fR
.SH ARGUMENTS
.AS "Tk_Anchor" *anchorPtr
.AP Tcl_Interp *interp in
Interpreter to use for error reporting, or NULL.
.AP Tcl_Obj *objPtr in/out
String value contains name of anchor point: \fBn\fR, \fBne\fR,
\fBe\fR, \fBse\fR, \fBs\fR, \fBsw\fR, \fBw\fR, \fBnw\fR, or \fBcenter\fR;
internal rep will be modified to cache corresponding Tk_Anchor.
.AP "const char" *string in
Same as \fIobjPtr\fR except description of anchor point is passed as
a string.
.AP int *anchorPtr out
Pointer to location in which to store anchor position corresponding to
\fIobjPtr\fR or \fIstring\fR.
.AP Tk_Anchor anchor in
Anchor position, e.g. \fBTCL_ANCHOR_CENTER\fR.
.BE
.SH DESCRIPTION
.PP
\fBTk_GetAnchorFromObj\fR places in \fI*anchorPtr\fR an anchor position
(enumerated type \fBTk_Anchor\fR)
corresponding to \fIobjPtr\fR's value. The result will be one of
\fBTK_ANCHOR_N\fR, \fBTK_ANCHOR_NE\fR, \fBTK_ANCHOR_E\fR, \fBTK_ANCHOR_SE\fR,
\fBTK_ANCHOR_S\fR, \fBTK_ANCHOR_SW\fR, \fBTK_ANCHOR_W\fR, \fBTK_ANCHOR_NW\fR,
or \fBTK_ANCHOR_CENTER\fR.
Anchor positions are typically used for indicating a point on an object
that will be used to position the object, e.g. \fBTK_ANCHOR_N\fR means
position the top center point of the object at a particular place.
.PP
Under normal circumstances the return value is \fBTCL_OK\fR and
\fIinterp\fR is unused.
If \fIstring\fR doesn't contain a valid anchor position
or an abbreviation of one of these names, \fBTCL_ERROR\fR is returned,
\fI*anchorPtr\fR is unmodified, and an error message is
stored in \fIinterp\fR's result if \fIinterp\fR isn't NULL.
\fBTk_GetAnchorFromObj\fR caches information about the return
value in \fIobjPtr\fR, which speeds up future calls to
\fBTk_GetAnchorFromObj\fR with the same \fIobjPtr\fR.
.PP
\fBTk_GetAnchor\fR is identical to \fBTk_GetAnchorFromObj\fR except
that the description of the anchor is specified with a string instead
of an object. This prevents \fBTk_GetAnchor\fR from caching the
return value, so \fBTk_GetAnchor\fR is less efficient than
\fBTk_GetAnchorFromObj\fR.
.PP
\fBTk_NameOfAnchor\fR is the logical inverse of \fBTk_GetAnchor\fR.
Given an anchor position such as \fBTK_ANCHOR_N\fR it returns a
statically-allocated string corresponding to \fIanchor\fR.
If \fIanchor\fR isn't a legal anchor value, then
``unknown anchor position'' is returned.
.SH KEYWORDS
anchor position
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