Tk_GetAnchorFromObj(3tk) Tk Library Procedures Tk_GetAnchorFromObj(3tk)
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NAME
Tk_GetAnchorFromObj, Tk_GetAnchor, Tk_NameOfAnchor - translate between
strings and anchor positions
SYNOPSIS
#include <tk.h>
int
Tk_GetAnchorFromObj(interp, objPtr, anchorPtr)
int
Tk_GetAnchor(interp, string, anchorPtr)
const char *
Tk_NameOfAnchor(anchor)
ARGUMENTS
Tcl_Interp *interp (in) Interpreter to use for error report-
ing, or NULL.
Tcl_Obj *objPtr (in/out) String value contains name of anchor
point: “n”, “ne”, “e”, “se”, “s”,
“sw”, “w”, “nw”, or “center”; inter-
nal rep will be modified to cache
corresponding Tk_Anchor. In the case
of “center” on input, a non-empty
abbreviation of it may also be used
on input.
const char *string (in) Same as objPtr except description of
anchor point is passed as a string.
int *anchorPtr (out) Pointer to location in which to
store anchor position corresponding
to objPtr or string.
Tk_Anchor anchor (in) Anchor position, e.g. TCL_AN-
CHOR_CENTER.
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DESCRIPTION
Tk_GetAnchorFromObj places in *anchorPtr an anchor position (enumerated
type Tk_Anchor) corresponding to objPtr's value. The result will be
one of TK_ANCHOR_N, TK_ANCHOR_NE, TK_ANCHOR_E, TK_ANCHOR_SE, TK_AN-
CHOR_S, TK_ANCHOR_SW, TK_ANCHOR_W, TK_ANCHOR_NW, or TK_ANCHOR_CENTER.
Anchor positions are typically used for indicating a point on an object
that will be used to position the object, e.g. TK_ANCHOR_N means posi-
tion the top center point of the object at a particular place.
Under normal circumstances the return value is TCL_OK and interp is un-
used. If string does not contain a valid anchor position or an abbre-
viation of one of these names, TCL_ERROR is returned, *anchorPtr is un-
modified, and an error message is stored in interp's result if interp
is not NULL. Tk_GetAnchorFromObj caches information about the return
value in objPtr, which speeds up future calls to Tk_GetAnchorFromObj
with the same objPtr.
Tk_GetAnchor is identical to Tk_GetAnchorFromObj except that the de-
scription of the anchor is specified with a string instead of an ob-
ject. This prevents Tk_GetAnchor from caching the return value, so
Tk_GetAnchor is less efficient than Tk_GetAnchorFromObj.
Tk_NameOfAnchor is the logical inverse of Tk_GetAnchor. Given an an-
chor position such as TK_ANCHOR_N it returns a statically-allocated
string corresponding to anchor. If anchor is not a legal anchor value,
then “unknown anchor position” is returned.
KEYWORDS
anchor position
Tk 8.1 Tk_GetAnchorFromObj(3tk)
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