NAME

       Tk_GetPixelsFromObj, Tk_GetPixels, Tk_GetMMFromObj, Tk_GetScreenMM - translate between strings and screen
       units

SYNOPSIS

       #include <tk.h>

       int                                                                                                       2
       Tk_GetPixelsFromObj(interp, tkwin, objPtr, intPtr)                                                        2

       int
       Tk_GetPixels(interp, tkwin, string, intPtr)

       int                                                                                                       2
       Tk_GetMMFromObj(interp, tkwin, objPtr, doublePtr)                                                         2

       int
       Tk_GetScreenMM(interp, tkwin, string, doublePtr)

ARGUMENTS

       Tcl_Interp   *interp    (in)      Interpreter to use for error reporting.

       Tk_Window    tkwin      (in)      Window whose screen geometry determines the conversion between absolute
                                         units and pixels.

       Tcl_Obj      *objPtr    (in/out)                                                                          2
                                         String  value  specifies a distance on the screen; internal rep will be 2
                                         modified to cache converted distance.                                   2

       CONST char   *string    (in)                                                                              2
                                         Same as objPtr except specification of distance is passed as a string.

       int          *intPtr    (out)     Pointer to location in which to store converted distance in pixels.

       double       *doublePtr (out)     Pointer  to  location  in  which  to  store   converted   distance   in
                                         millimeters.
_________________________________________________________________

DESCRIPTION

       These  procedures  take  as  argument  a  specification  of distance on the screen (objPtr or string) and 2
       compute the corresponding distance either in integer pixels or  floating-point  millimeters.   In  either
       case,  objPtr  or  string  specifies  a screen distance as a floating-point number followed by one of the 2
       following characters that indicates units:

       <none> The number specifies a distance in pixels.

       c      The number specifies a distance in centimeters on the screen.

       i      The number specifies a distance in inches on the screen.

       m      The number specifies a distance in millimeters on the screen.

       p      The number specifies a distance in printer's points (1/72 inch) on the screen.

       Tk_GetPixelsFromObj converts the value of objPtr to the nearest even number of  pixels  and  stores  that 2
       value  at  *intPtr.   It  returns  TCL_OK  under  normal  circumstances.  If an error occurs (e.g. objPtr 2
       contains a number followed by a character that isn't one of the ones above) then  TCL_ERROR  is  returned 2
       and  an  error  message  is  left  in  interp's  result if interp isn't NULL.  Tk_GetPixelsFromObj caches 2
       information about the return value in objPtr, which speeds up future calls  to  Tk_GetPixelsFromObj  with 2
       the same objPtr.                                                                                          2

       Tk_GetPixels  is  identical  to  Tk_GetPixelsFromObj  except that the screen distance is specified with a 2
       string instead of an object.  This prevents Tk_GetPixels from caching the return value,  so  Tk_GetAnchor 2
       is less efficient than Tk_GetPixelsFromObj.                                                               2

       Tk_GetMMFromObj  and  Tk_GetScreenMM  are  similar to Tk_GetPixelsFromObj and Tk_GetPixels (respectively) 2
       except that they convert the screen distance to millimeters and store a  double-precision  floating-point 2
       result at *doublePtr.

KEYWORDS

       centimeters, convert, inches, millimeters, pixels, points, screen units

Tk                                                     8.1                              Tk_GetPixelsFromObj(3tk)