Tk4.2 C API Man Page -- GetPixels (n)
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Tk_GetPixels, Tk_GetScreenMM - translate between strings and screen units
Tk_GetPixels(interp, tkwin, string, intPtr)
Tk_GetScreenMM(interp, tkwin, string, doublePtr)
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.
- *string (in) String that specifies a distance on the screen.
- *intPtr (out) Pointer to location in which to store converted distance in pixels.
- *doublePtr (out) Pointer to location in which to store converted distance in millimeters.
These two procedures take as argument a specification of distance on the screen (string) and compute the corresponding distance either in integer pixels or floating-point millimeters. In either case, string specifies a screen distance as a floating-point number followed by one of the following characters that indicates units:
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
- The number specifies a distance in millimeters on the screen.
Tk_GetPixels converts string to the nearest even number of pixels and stores that value at *intPtr. Tk_GetScreenMM converts string to millimeters and stores the doubleprecision floating-point result at *doublePtr.
- The number specifies a distance in printer's points (1/72 inch) on the screen.
Both procedures return TCL_OK under normal circumstances. If an error occurs (e.g. string 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->result.
centimeters, convert, inches, millimeters, pixels, points, screen units
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