Enable parallel CvtColorLoop for all platforms

modules/imgproc/src/color.cpp

@@ -157,8 +157,7 @@ template<> struct ColorChannel<float>
 ///////////////////////////// Top-level template function ////////////////////////////////
 
 template <typename Cvt>
-class CvtColorLoop_Invoker : 
-    public ParallelLoopBody
+class CvtColorLoop_Invoker : public ParallelLoopBody
 {
     typedef typename Cvt::channel_type _Tp;
 public:
@@ -170,18 +169,17 @@ public:
 
     virtual void operator()(const Range& range) const
     {
-        int i = range.start;
-        const uchar* yS = src.data + src.step * i;
-        uchar* yD = dst.data + dst.step * i;
+        const uchar* yS = src.ptr<uchar>(range.start);
+        uchar* yD = dst.ptr<uchar>(range.start);
 
-        for ( ; i < range.end; ++i, yS += src.step, yD += dst.step )
+        for( int i = range.start; i < range.end; ++i, yS += src.step, yD += dst.step )
             cvt((const _Tp*)yS, (_Tp*)yD, src.cols);
     }
 
 private:
-    const Mat src;
-    Mat dst;
-    const Cvt cvt;
+    const Mat& src;
+    Mat& dst;
+    const Cvt& cvt;
 
     CvtColorLoop_Invoker(const CvtColorLoop_Invoker&);
     const CvtColorLoop_Invoker& operator= (const CvtColorLoop_Invoker&);
@@ -190,13 +188,7 @@ private:
 template <typename Cvt>
 void CvtColorLoop(const Mat& src, Mat& dst, const Cvt& cvt)
 {
-    Range range(0, src.rows);
-    CvtColorLoop_Invoker<Cvt> invoker(src, dst, cvt);
-#if defined(_MSC_VER) || defined(__APPLE__)
-    parallel_for_(range, invoker);
-#else
-    invoker(range);
-#endif
+    parallel_for_(Range(0, src.rows), CvtColorLoop_Invoker<Cvt>(src, dst, cvt));
 }
 
 ////////////////// Various 3/4-channel to 3/4-channel RGB transformations /////////////////