Merge remote-tracking branch 'upstream/3.4' into merge-3.4

modules/core/src/copy.cpp

@@ -414,6 +414,29 @@ void Mat::copyTo( OutputArray _dst, InputArray _mask ) const
         copymask(ptrs[0], 0, ptrs[2], 0, ptrs[1], 0, sz, &esz);
 }
 
+
+static bool can_apply_memset(const Mat &mat, const Scalar &s, int &fill_value)
+{
+    // check if depth is 1 byte.
+    switch (mat.depth())
+    {
+    case CV_8U: fill_value = saturate_cast<uchar>( s.val[0] ); break;
+    case CV_8S: fill_value = saturate_cast<schar>( s.val[0] ); break;
+    default: return false;
+    }
+
+    // check if all element is same.
+    const int64* is = (const int64*)&s.val[0];
+    switch (mat.channels())
+    {
+    case 1: return true;
+    case 2: return (is[0] == is[1]);
+    case 3: return (is[0] == is[1] && is[1] == is[2]);
+    case 4: return (is[0] == is[1] && is[1] == is[2] && is[2] == is[3]);
+    default: return false;
+    }
+}
+
 Mat& Mat::operator = (const Scalar& s)
 {
     CV_INSTRUMENT_REGION();
@@ -434,6 +457,14 @@ Mat& Mat::operator = (const Scalar& s)
     }
     else
     {
+        int fill_value = 0;
+        if ( can_apply_memset(*this, s, fill_value) )
+        {
+            for (size_t i = 0; i < it.nplanes; i++, ++it)
+                memset(dptr, fill_value, elsize);
+            return *this;
+        }
+
         if( it.nplanes > 0 )
         {
             double scalar[12];

modules/core/src/cuda/gpu_mat.cu

@@ -561,7 +561,7 @@ void cv::cuda::GpuMat::convertTo(OutputArray _dst, int rtype, Stream& stream) co
         {convertToNoScale<double, uchar>, convertToNoScale<double, schar>, convertToNoScale<double, ushort>, convertToNoScale<double, short>, convertToNoScale<double, int>, convertToNoScale<double, float>, 0}
     };
 
-    funcs[sdepth][ddepth](reshape(1), dst.reshape(1), stream);
+    funcs[sdepth][ddepth](src.reshape(1), dst.reshape(1), stream);
 }
 
 void cv::cuda::GpuMat::convertTo(OutputArray _dst, int rtype, double alpha, double beta, Stream& stream) const
@@ -591,7 +591,7 @@ void cv::cuda::GpuMat::convertTo(OutputArray _dst, int rtype, double alpha, doub
         {convertToScale<double, uchar>, convertToScale<double, schar>, convertToScale<double, ushort>, convertToScale<double, short>, convertToScale<double, int>, convertToScale<double, float>, convertToScale<double, double>}
     };
 
-    funcs[sdepth][ddepth](reshape(1), dst.reshape(1), alpha, beta, stream);
+    funcs[sdepth][ddepth](src.reshape(1), dst.reshape(1), alpha, beta, stream);
 }
 
 void cv::cuda::convertFp16(InputArray _src, OutputArray _dst, Stream& stream)

modules/core/src/ocl.cpp

@@ -6464,6 +6464,9 @@ struct Image2D::Impl
             CV_Error(Error::OpenCLApiCallError, "OpenCL runtime not found!");
 
         cl_context context = (cl_context)Context::getDefault().ptr();
+        if (!context)
+            return false;
+
         // Figure out how many formats are supported by this context.
         cl_uint numFormats = 0;
         cl_int err = clGetSupportedImageFormats(context, CL_MEM_READ_WRITE,