r10530: fix argument list

[cl-photo.git] / fov.lisp

diff --git a/fov.lisp b/fov.lisp
index 6fec649da285882846259180f3037c6fdaf74cd6..fba5ce9d91109b423173720ab17f099105406917 100644 (file)
--- a/fov.lisp
+++ b/fov.lisp
@@ -208,14 +208,28 @@ Returns: focal-length object-distance image-distance magnification bellows-facto
   "Returns the bellows factor, the ratio of effective aperature to actual aperture."
   (1+ (magnification :focal-length focal-length :object-distance object-distance)))
 
-(defun extension-tube (focal-length &key original-object-distance new-object-distance original-image-distance
-                                        new-object-distnace original-magnification new-magification
-                                        extension-length (units :feet))
+(defun extension-tube (focal-length &key original-object-distance original-image-distance original-magnification
+                      new-object-distance new-image-distance new-magnification extension-length (units :feet))
   "Computes the parameters for using extension tubes.
 Requires: 1. original-object-distance, original-image-distance, or original-magnification
           2. new-object-distance, new-image-distance, new-magnification, or extension-length
-Returns: original-object-distance, original-image-distance, original-magnification,
+Returns: original-object-distance, original-image-distance, original-magnification, original-bellows-factor
          new-object-distance, new-image-distance, new-magnification, extension-length."
-  )
+  
+  (multiple-value-bind (focal-length o-od o-id o-m o-bf)
+      (close-up :focal-length focal-length :object-distance original-object-distance
+               :image-distance original-image-distance :magnification original-magnification :units units)
+    
+    (cond
+     (extension-length
+      (multiple-value-bind (focal-length n-od n-id n-m n-bf)
+         (close-up :focal-length focal-length :image-distance (+ o-id extension-length) :units units)
+       (values o-od o-id o-m o-bf n-od n-id n-m n-bf extension-length)))
+     ((not extension-length)
+      (multiple-value-bind (focal-length n-od n-id n-m n-bf)
+         (close-up :focal-length focal-length :object-distance new-object-distance
+                   :image-distance new-image-distance :magnification new-magnification :units units)
+       (values o-od o-id o-m o-bf n-od n-id n-m n-bf (- n-id o-id)))))))
+