diff --git a/README.rdoc b/README.rdoc
index 16de2b1..6708c52 100644
--- a/README.rdoc
+++ b/README.rdoc
@@ -24,13 +24,6 @@ Ruby/OpenCV relies on the OpenCV library.
 See http://opencv.willowgarage.com/wiki/InstallGuide
 
 
-* ffcall (optional)
-ffcall is needed to use GUI trackbar component.
-Other GUI components work without ffcall.
-
-See http://www.haible.de/bruno/packages-ffcall.html
-
-
 == INSTALLATION:
 === Install Ruby/OpenCV manually
 ==== Unix/Linux/Mac
diff --git a/ext/opencv/opencv.h b/ext/opencv/opencv.h
index 8f51b7a..388a7a0 100644
--- a/ext/opencv/opencv.h
+++ b/ext/opencv/opencv.h
@@ -38,10 +38,6 @@ extern "C" {
 #include <st.h>
 #endif
 
-#ifdef HAVE_CALLBACK_H
-#include <callback.h> // callhack.h is ffcall header
-#endif
-
 #ifdef HAVE_STDARG_H
 #include <stdarg.h>
 #define va_init_list(a,b) va_start(a,b)
diff --git a/ext/opencv/window.cpp b/ext/opencv/window.cpp
index 8432dca..1e4533a 100644
--- a/ext/opencv/window.cpp
+++ b/ext/opencv/window.cpp
@@ -306,6 +306,12 @@ rb_show_image(int argc, VALUE *argv, VALUE self)
   return self;
 }
 
+void
+trackbar_callback(int value, void* block)
+{
+  rb_funcall((VALUE)block, rb_intern("call"), 1, INT2NUM(value));
+}
+
 /*
  * call-seq:
  *   set_trackbar(<i>trackbar</i>)
@@ -315,15 +321,6 @@ rb_show_image(int argc, VALUE *argv, VALUE self)
  * Create Trackbar on this window. Return new Trackbar.
  * see Trackbar.new
  */
-#ifdef HAVE_CALLBACK_H
-void
-trackbar_callback(VALUE block, va_alist ap)
-{
-  va_start_void(ap);
-  rb_funcall(block, rb_intern("call"), 1, INT2FIX(va_arg_int(ap)));
-  va_return_void(ap);
-}
-
 VALUE
 rb_set_trackbar(int argc, VALUE *argv, VALUE self)
 {
@@ -335,10 +332,9 @@ rb_set_trackbar(int argc, VALUE *argv, VALUE self)
     instance = cTrackbar::rb_initialize(argc, argv, cTrackbar::rb_allocate(cTrackbar::rb_class()));
   }
   Trackbar *trackbar = TRACKBAR(instance);
-  void *callback = (void *)alloc_callback(&trackbar_callback, trackbar->block);
   try {
-    cvCreateTrackbar(trackbar->name, GET_WINDOW_NAME(self), &(trackbar->val), trackbar->maxval,
-		     (CvTrackbarCallback)callback);
+    cv::createTrackbar(trackbar->name, GET_WINDOW_NAME(self), &(trackbar->val), trackbar->maxval,
+		       (cv::TrackbarCallback)trackbar_callback, (void*)(trackbar->block));
   }
   catch (cv::Exception& e) {
     raise_cverror(e);
@@ -349,17 +345,10 @@ rb_set_trackbar(int argc, VALUE *argv, VALUE self)
   }
   return instance;
 }
-#else
-VALUE
-rb_set_trackbar(int argc, VALUE *argv, VALUE self)
-{
-  rb_raise(rb_eFatal, "ffcall is required to use Window#set_trackbar");
-  return Qnil;
-}
-#endif // HAVE_CALLBACK_H
 
 void
-on_mouse(int event, int x, int y, int flags, void* param) {
+on_mouse(int event, int x, int y, int flags, void* param)
+{
   VALUE block = (VALUE)param;
   if (rb_obj_is_kind_of(block, rb_cProc))
     rb_funcall(block, rb_intern("call"), 1, cMouseEvent::new_object(event, x, y, flags));
diff --git a/extconf.rb b/extconf.rb
index 67c1f83..d77f5dd 100755
--- a/extconf.rb
+++ b/extconf.rb
@@ -16,11 +16,6 @@ require "mkmf"
 # extconf.rb --with-opencv-dir=/path/to/opencv
 
 dir_config("opencv", "/usr/local/include", "/usr/local/lib")
-if CONFIG["arch"].include?("darwin")
-  dir_config("ffcall", "/opt/local/include", "/opt/local/lib")
-else
-  dir_config("ffcall", "/usr/local/include", "/usr/local/lib")
-end
 dir_config("libxml2", "/usr/include", "/usr/lib")
 
 opencv_headers = ["opencv2/core/core_c.h", "opencv2/core/core.hpp", "opencv2/imgproc/imgproc_c.h",
@@ -63,17 +58,6 @@ have_header("stdarg.h")
 # check require functions.
 # todo
 
-# optional libraies check.
-puts ">> ----- optional -----"
-puts ">> check ffcall..."
-# check ffcall
-if have_library("callback") && have_header("callback.h")
-  puts ">> support OpenCV::GUI::Window#set_trackbar"
-else
-  puts ">> ! unsupport OpenCV::GUI::Window#set_trackbar (if need it. install ffcall)"
-  puts "http://www.haible.de/bruno/packages-ffcall.html"
-end
-
 # Quick fix for 1.8.7
 $CFLAGS << " -I#{File.dirname(__FILE__)}/ext/opencv"