added cvtColor on gpu (supports conversion between RGB, BGR and GRAY)

modules/gpu/CMakeLists.txt

 
 set(name "gpu")
-set(DEPS "opencv_core")
+set(DEPS "opencv_core" "opencv_imgproc")
 
 set(OPENCV_LINKER_LIBS ${OPENCV_LINKER_LIBS} opencv_gpu)
 

modules/gpu/include/opencv2/gpu/gpu.hpp

@@ -365,6 +365,9 @@ namespace cv
         // Acync version
         CV_EXPORTS void reprojectImageTo3D_GPU(const GpuMat& disp, GpuMat& xyzw, const Mat& Q, const Stream& stream);
 
+        CV_EXPORTS void cvtColor_GPU(const GpuMat& src, GpuMat& dst, int code, int dcn = 0);
+        CV_EXPORTS void cvtColor_GPU(const GpuMat& src, GpuMat& dst, int code, int dcn, const Stream& stream);
+
         //////////////////////////////// StereoBM_GPU ////////////////////////////////
 
         class CV_EXPORTS StereoBM_GPU

modules/gpu/src/precomp.hpp

@@ -55,6 +55,7 @@
 #include <vector>
 
 #include "opencv2/gpu/gpu.hpp"
+#include "opencv2/imgproc/types_c.h"
 
 #if defined(HAVE_CUDA)