Seth Woolley's Man Viewer

Tk_GetScreenMM(3) - Tk_GetMMFromObj, Tk_GetPixels, Tk_GetPixelsFromObj, Tk_GetScreenMM - translate between strings and screen units - man 3 Tk_GetScreenMM

([section] manual, -k keyword, -K [section] search, -f whatis)
man plain no title

Tk_GetPixelsFromObj(3)       Tk Library Procedures      Tk_GetPixelsFromObj(3)



______________________________________________________________________________

NAME
       Tk_GetPixelsFromObj,  Tk_GetPixels,  Tk_GetMMFromObj,  Tk_GetScreenMM -
       translate between strings and screen units(1,7)

SYNOPSIS
       #include <tk.h>

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

       int
       Tk_GetPixels(interp, tkwin, string(3,n), intPtr)

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

       int
       Tk_GetScreenMM(interp, tkwin, string(3,n), doublePtr)

ARGUMENTS
       Tcl_Interp   *interp    (in(1,8))      Interpreter to use for error(8,n)  report-
                                         ing.

       Tk_Window    tkwin      (in(1,8))      Window  whose  screen geometry deter-
                                         mines the conversion between absolute
                                         units(1,7) and pixels.

       Tcl_Obj      *objPtr    (in(1,8)/out)                                        ||
                                         String value specifies a distance  on |
                                         the screen; internal rep will be mod- |
                                         ified to cache converted distance.    |

       CONST                                                                   |
       char   *string(3,n)    (in(1,8))                                            |     |
                                         Same  as  objPtr except specification |
                                         of distance is passed as a string.

       int          *intPtr    (out)     Pointer to location in(1,8) which to store
                                         converted distance in(1,8) pixels.

       double       *doublePtr (out)     Pointer to location in(1,8) which to store
                                         converted distance in(1,8) millimeters.
_________________________________________________________________


DESCRIPTION
       These procedures take as argument a specification of  distance  on  the |
       screen (objPtr or string(3,n)) and compute the corresponding distance either
       in(1,8) integer pixels  or  floating-point  millimeters.   In  either  case, |
       objPtr or string(3,n) specifies a screen distance as a floating-point number
       followed by one of the following characters that indicates units:

       <none> The number specifies a distance in(1,8) pixels.

       c      The number specifies a distance in(1,8) centimeters on the screen.

       i      The number specifies a distance in(1,8) inches on the screen.

       m      The number specifies a distance in(1,8) millimeters on the screen.

       p      The number specifies a distance in(1,8) 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 value at *intPtr.  It  returns  TCL_OK |
       under normal circumstances.  If an error(8,n) occurs (e.g. objPtr contains a |
       number followed by a character that isn't one of the ones  above)  then |
       TCL_ERROR  is  returned and an error(8,n) message is left in(1,8) interp's result |
       if(3,n) interp isn't NULL.  Tk_GetPixelsFromObj caches information about the |
       return  value  in(1,8) objPtr, which speeds up future calls to Tk_GetPixels- |
       FromObj with the same objPtr.                                           |

       Tk_GetPixels is identical to Tk_GetPixelsFromObj except that the screen |
       distance  is  specified  with a string(3,n) instead of an object.  This pre- |
       vents Tk_GetPixels from caching the return value,  so  Tk_GetAnchor  is |
       less(1,3) efficient than Tk_GetPixelsFromObj.                                |

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


KEYWORDS
       centimeters, convert, inches, millimeters, pixels, points, screen units(1,7)



Tk                                    8.1               Tk_GetPixelsFromObj(3)

References for this manual (incoming links)