;;;; -*- Mode: LISP; Syntax: ANSI-Common-Lisp; Base: 10; Package: photo -*-
;;;; *************************************************************************
;;;; FILE IDENTIFICATION
;;;;
;;;; Name:          convert.lisp
;;;; Purpose:       Conversions functions for cl-photo
;;;; Programmer:    Kevin M. Rosenberg
;;;; Date Started:  April 2005
;;;;
;;;; $Id: package.lisp 8596 2004-02-03 18:32:50Z kevin $
;;;;
;;;; This file, part of cl-photo, is Copyright (c) 2005 by Kevin Rosenberg.
;;;; Rights of modification and redistribution are in the LICENSE file.
;;;;
;;;; *************************************************************************

(in-package #:photo)

(defconstant +radian->degrees+ (/ 360d0 pi 2))
(defconstant +inches->mm+ 25.4)

(defun diagonal (x y)
  (sqrt (+ (* x x) (* y y))))

(defun radians->degrees (r)
  (* +radian->degrees+ r))

(defun mm->feet (d)
  (/ d +inches->mm+ 12))

(defun feet->mm (d)
  (* d 12 +inches->mm+))