- Tk_GetPixelsFromObj, Tk_GetPixels, Tk_GetMMFromObj, Tk_GetScreenMM - translate between strings and screen units
Tk_GetPixelsFromObj, Tk_GetPixels, Tk_GetMMFromObj, Tk_GetScreenMM - translate between strings and screen units
Tk_GetPixelsFromObj(interp, tkwin, objPtr, intPtr)
Tk_GetPixels(interp, tkwin, string, intPtr)
Tk_GetMMFromObj(interp, tkwin, objPtr, doublePtr)
Tk_GetScreenMM(interp, tkwin, string, doublePtr)
These procedures take as argument a specification of distance on
the screen (objPtr or string) and 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 following characters
that indicates units:
- 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)
String value specifies a distance on the screen;
internal rep will be modified to cache converted distance.
- char *string (in)
Same as objPtr except specification of distance is passed as
- 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.
The number specifies a distance in pixels.
The number specifies a distance in centimeters on the screen.
The number specifies a distance in inches on the screen.
The number specifies a distance in millimeters on the screen.
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 value at *intPtr.
It returns TCL_OK under normal circumstances.
If an error 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 message is left
in interp's result if interp isn't NULL.
Tk_GetPixelsFromObj caches information about the return
value in objPtr, which speeds up future calls to
Tk_GetPixelsFromObj with the same objPtr.
Tk_GetPixels is identical to Tk_GetPixelsFromObj except
that the screen distance is specified with a string instead
of an object. This prevents Tk_GetPixels from caching the
return value, so Tk_GetAnchor is less efficient than
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.
centimeters, convert, inches, millimeters, pixels, points, screen units
Copyright © 1990 The Regents of the University of California.
Copyright © 1994-1998 Sun Microsystems, Inc.
Copyright © 1995-1997 Roger E. Critchlow Jr.