From: Vitaly Mayatskikh <v.mayatskih@gmail.com>
Date: Mon, 7 Sep 2009 11:37:59 +0000 (+0200)
Subject: New function: get-control.
X-Git-Url: https://repo.or.cz/w/cl-v4l2.git/commitdiff_plain/12256ab5bf8c1f8a8679cdbf5f2188dd4291d30a

New function: get-control.

This is the opposite of set-control.
---

diff --git a/package.lisp b/package.lisp
index 94baa81..6478142 100644
--- a/package.lisp
+++ b/package.lisp
@@ -47,6 +47,7 @@
    #:get-frame
    #:put-frame
    #:set-control
+   #:get-control
 
    ;; structs
    #:capability
diff --git a/v4l2.lisp b/v4l2.lisp
index 6e0fcd1..767d38d 100644
--- a/v4l2.lisp
+++ b/v4l2.lisp
@@ -215,3 +215,15 @@
 	  (setf id ctrl-id
 		value (+ minimum (round (* level (- maximum minimum))))))
         (ioctl fd vidioc-s-ctrl control)))))
+
+(defun get-control (fd ctrl-id)
+  "Get control level (in range of 0.0-1.0)."
+  (with-foreign-object (query 'queryctrl)
+    (with-foreign-slots ((id minimum maximum) query queryctrl)
+      (setf id ctrl-id)
+      (ioctl fd vidioc-queryctrl query)
+      (with-foreign-object (control 'control)
+	(with-foreign-slots ((id value) control control)
+	  (setf id ctrl-id)
+	  (ioctl fd vidioc-g-ctrl control)
+	  (/ (- value minimum) (- maximum minimum)))))))