Added the toMat() routine for converting from a dlib style image to an

OpenCV cv::Mat image.

dlib/opencv.h

@@ -4,6 +4,7 @@
 #define DLIB_OPEnCV_HEADER
 
 #include "opencv/cv_image.h"
+#include "opencv/to_open_cv.h"
 
 #endif // DLIB_OPEnCV_HEADER
 

dlib/opencv/to_open_cv.h

+// Copyright (C) 2012  Davis E. King (davis@dlib.net)
+// License: Boost Software License   See LICENSE.txt for the full license.
+#ifndef DLIB_TO_OPEN_Cv_H__
+#define DLIB_TO_OPEN_Cv_H__
+
+#include "to_open_cv_abstract.h"
+#include "../pixel.h"
+
+namespace dlib
+{
+    template <
+        typename image_type
+        >
+    cv::Mat toMat (
+        image_type& img
+    )
+    {
+        if (img.size() == 0)
+            return cv::Mat();
+
+        typedef typename image_type::type type;
+        if (pixel_traits<type>::num == 1)
+        {
+            return cv::Mat(img.nr(), img.nc(), cv::DataType<type>::type, &img[0][0], img.width_step());
+        }
+        else
+        {
+            int depth = sizeof(typename pixel_traits<type>::basic_pixel_type)*8;
+            int channels = pixel_traits<type>::num;
+            int type CV_MAKETYPE(depth, channels);
+            return cv::Mat(img.nr(), img.nc(), type, &img[0][0], img.width_step());
+        }
+    }
+}
+
+#endif // DLIB_TO_OPEN_Cv_H__
+

dlib/opencv/to_open_cv_abstract.h

+// Copyright (C) 2012  Davis E. King (davis@dlib.net)
+// License: Boost Software License   See LICENSE.txt for the full license.
+#undef DLIB_TO_OPEN_Cv_ABSTRACT__
+#ifdef DLIB_TO_OPEN_Cv_ABSTRACT__
+
+#include "../pixel.h"
+
+namespace dlib
+{
+    template <
+        typename image_type
+        >
+    cv::Mat toMat (
+        image_type& img
+    );
+    /*!
+        requires
+            - image_type == an implementation of dlib/array2d/array2d_kernel_abstract.h
+            - pixel_traits<typename image_type::type> is defined
+        ensures
+            - returns an OpenCV Mat object which represents the same image as img.  This
+              is done by setting up the Mat object to point to the same memory as img.
+              Therefore, the returned Mat object is valid only as long as pointers
+              to the pixels in img remain valid.
+    !*/
+}
+
+#endif // DLIB_TO_OPEN_Cv_ABSTRACT__
+
+
+