Tk_GetAnchorFromObj(3)

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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; internal rep will be mod- |
                                          ified    to    cache   corresponding |
                                          Tk_Anchor.                           |

       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_ANCHOR_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_ANCHOR_S, TK_ANCHOR_SW, TK_ANCHOR_W, TK_ANCHOR_NW, or TK_ANCHOR_CEN- |
       TER.  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 |
       position the top center point of the object at a particular place.      |

       Under normal circumstances the return value is  TCL_OK  and  interp  is |
       unused.  If string doesn't contain a valid anchor position or an abbre- |
       viation of one of these names, TCL_ERROR  is  returned,  *anchorPtr  is |
       unmodified, and an error message is stored in interp's result if interp |
       isn't 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 |
       description  of  the  anchor  is  specified with a string instead of an |
       object.  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
       anchor position such as TK_ANCHOR_N it returns  a  statically-allocated
       string  corresponding to anchor.  If anchor isn't a legal anchor value,
       then ``unknown anchor position'' is returned.

KEYWORDS

       anchor position

Tk                                    8.1               Tk_GetAnchorFromObj(3)