Add 90 degree rotation methods. This provides a quick simple way of doing 90 degree rotations.

Also fix warnings that show up on other compilers in test builds.

modules/core/include/opencv2/core.hpp

@@ -1022,6 +1022,24 @@ around both axes.
 */
 CV_EXPORTS_W void flip(InputArray src, OutputArray dst, int flipCode);
 
+enum RotateFlags {
+    ROTATE_90 = 0, //Rotate 90 degrees clockwise
+    ROTATE_180 = 1, //Rotate 180 degrees clockwise
+    ROTATE_270 = 2, //Rotate 270 degrees clockwise
+};
+/** @brief Rotates a 2D array in multiples of 90 degrees.
+The function rotate rotates the array in one of three different ways:
+*   Rotate by 90 degrees clockwise (rotateCode = ROTATE_90).
+*   Rotate by 180 degrees clockwise (rotateCode = ROTATE_180).
+*   Rotate by 270 degrees clockwise (rotateCode = ROTATE_270).
+@param src input array.
+@param dst output array of the same type as src.  The size is the same with ROTATE_180,
+and the rows and cols are switched for ROTATE_90 and ROTATE_270.
+@param rotateCode an enum to specify how to rotate the array; see the enum RotateFlags
+@sa transpose , repeat , completeSymm, flip, RotateFlags
+*/
+CV_EXPORTS_W void rotate(InputArray src, OutputArray dst, int rotateCode);
+
 /** @brief Fills the output array with repeated copies of the input array.
 
 The function cv::repeat duplicates the input array one or more times along each of the two axes:

modules/core/src/copy.cpp

@@ -826,6 +826,50 @@ void flip( InputArray _src, OutputArray _dst, int flip_mode )
         flipHoriz( dst.ptr(), dst.step, dst.ptr(), dst.step, dst.size(), esz );
 }
 
+#ifdef HAVE_OPENCL
+
+static bool ocl_rotate(InputArray _src, OutputArray _dst, int rotateMode)
+{
+    switch (rotateMode)
+    {
+    case ROTATE_90:
+        flip(_src.getUMat().t(), _dst, 1);
+        break;
+    case ROTATE_180:
+        flip(_src, _dst, -1);
+        break;
+    case ROTATE_270:
+        flip(_src.getUMat().t(), _dst, 0);
+        break;
+    default:
+        break;
+    }
+    return true;
+}
+#endif
+
+void rotate(InputArray _src, OutputArray _dst, int rotateMode)
+{
+    CV_Assert(_src.dims() <= 2);
+
+    CV_OCL_RUN(_dst.isUMat(), ocl_rotate(_src, _dst, rotateMode))
+
+    switch (rotateMode)
+    {
+    case ROTATE_90:
+        flip(_src.getMat().t(), _dst, 1);
+        break;
+    case ROTATE_180:
+        flip(_src, _dst, -1);
+        break;
+    case ROTATE_270:
+        flip(_src.getMat().t(), _dst, 0);
+        break;
+    default:
+        break;
+    }
+}
+
 #if defined HAVE_OPENCL && !defined __APPLE__
 
 static bool ocl_repeat(InputArray _src, int ny, int nx, OutputArray _dst)