Tk4.2 C API Man Page -- GetPixels (n)
Table of Contents

NAME

Tk_GetPixels, Tk_GetScreenMM - translate between strings and screen units

SYNOPSIS

#include <tk.h>

int
Tk_GetPixels(interp, tkwin, string, intPtr)

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.

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.

DESCRIPTION

 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:

<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_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.

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.

KEYWORDS

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

Table of Contents