Several type of formal refactoring:

1. someMatrix.data -> someMatrix.prt()
2. someMatrix.data + someMatrix.step * lineIndex -> someMatrix.ptr( lineIndex )
3. (SomeType*) someMatrix.data -> someMatrix.ptr<SomeType>()
4. someMatrix.data -> !someMatrix.empty() ( or !someMatrix.data -> someMatrix.empty() ) in logical expressions

samples/cpp/tutorial_code/ImgTrans/HoughCircle_Demo.cpp

@@ -65,7 +65,7 @@ int main(int argc, char** argv)
     // Read the image
     src = imread( argv[1], 1 );
 
-    if( !src.data )
+    if( src.empty() )
     {
         std::cerr<<"Invalid input image\n";
         std::cout<<usage;