---
name: "GetPixels"
section: "2"
platform: "linux"
package: "perl-tk"
version: "b11.02-5"
release: "Debian 1.3 (Bo)"
platforms: ["linux"]
url: "https://new.carta.tech/GetPixels"
---

# GetPixels(2)

translate between strings and screen units

## 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

Interpreter to use for error reporting. Window whose screen geometry determines the conversion between absolute units and pixels.  String that specifies a distance on the screen. Pointer to location in which to store converted distance in pixels. 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 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*.

## KEYWORDS

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