Tk::pTk::GetPixels, Tk::pTk::GetScreenMM - translate between strings and screen units
int Tk_GetPixels(interp, tkwin, string, intPtr)
int 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.
- char *string (in)
String that specifies a distance on the screen.
- 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.
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 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_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 double-precision floating-point result at *doublePtr.
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