trusty (3) Tk_NameOfAnchor.3tk.gz

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 reporting, 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 modified  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.
_________________________________________________________________

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_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 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 does not contain a
       valid anchor position or an abbreviation of one of these names,  TCL_ERROR  is  returned,  *anchorPtr  is
       unmodified, 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 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 is not a  legal  anchor  value,
       then “unknown anchor position” is returned.

KEYWORDS

       anchor position