We present the Higres system - a visualization tool, an editor for clustered graphs and a platform for execution and animation of graph algorithms. Higres can handle any attributed graphs and perform animated semantic processing of them. The semantics of a graph can be defined by the user in the graph editor. The user can also create new external modules to process graphs with defined semantics. In addition we provide a possibility to extend system with new graph drawing algorithms by using special type of external modules for this purpose. We provide an easy to use C++ library for implementation of both types of extensions.