X-Git-Url: http://git.kpe.io/?a=blobdiff_plain;f=fov.lisp;h=6a43317c6131e828c373443bcea690510d79fac1;hb=4e83bf8dbe167504969d64842ccf8bfae859ca9b;hp=6cc5bb3a8a5095717bf4338faf4dc10dc229253e;hpb=2502270d59bbf71c29d82486997d38a3981b307c;p=cl-photo.git

diff --git a/fov.lisp b/fov.lisp
index 6cc5bb3..6a43317 100755
--- a/fov.lisp
+++ b/fov.lisp
@@ -9,8 +9,11 @@
 ;;;;
 ;;;; $Id$
 ;;;;
-;;;; This file, part of cl-photo, is Copyright (c) 2005 by Kevin Rosenberg.
-;;;; Rights of modification and redistribution are in the LICENSE file.
+;;;; This file, part of cl-photo, is Copyright (c) 2005 by Kevin M. Rosenberg
+;;;;
+;;;; cl-photo users are granted the rights to distribute and use this software
+;;;; as governed by the terms of the GNU General Public License v2
+;;;; (http://www.gnu.org/licenses/gpl.html)
 ;;;;
 ;;;; *************************************************************************
 
@@ -41,28 +44,19 @@
    (fov-one-dim focal-length (diagonal frame-width frame-height)
                 :projection projection)))
 
+(defun fov-distance (focal-length frame-width frame-height distance
+                                  &key (projection :rectilinear))
+  "Returns the field of view and image magnificaion ratio at a given distance.
+NOTE: magnification assumes that distance is in the same units as frame size: mm"
+  (multiple-value-bind (fov-width fov-height fov-diagonal)
+      (fov focal-length frame-width frame-height :projection projection)
+    (let* ((d-width (* distance (sin (degrees->radians fov-width))))
+           (d-height (* distance (sin (degrees->radians fov-height))))
+           (d-diagonal (* distance (sin (degrees->radians fov-diagonal))))
+           (mag (/ frame-width d-width))) 
+      (values d-width d-height d-diagonal mag))))
+
 (defun fov-format (focal-length format &key (projection :rectilinear))
   "Returns the angle of field of view for a focal length and frame size at infinity"
-  (ecase format
-    (:aps-c
-     (fov focal-length 22.7 15.1 :projection projection))
-    (:aps
-     (fov focal-length 24 18 :projection projection))
-    (:35mm
-     (fov focal-length 36 24 :projection projection))
-    (:4.5x6
-     (fov focal-length 45 60 :projection projection))
-    (:6x6
-     (fov focal-length 60 60 :projection projection))
-    (:6x7
-     (fov focal-length 60 70 :projection projection))
-    (:6x9
-     (fov focal-length 60 90 :projection projection))
-    (:4x5
-     (fov focal-length (* 4 +inches->mm+) (* 5 +inches->mm+)
-          :projection projection))
-    (:8x10
-     (fov focal-length (* 8 +inches->mm+) (* 10 +inches->mm+)
-          :projection projection))
-    ))
-
+  (let ((dim (format-dimensions format))) 
+    (fov focal-length (car dim) (cdr dim) :projection projection)))