Interesting events and state mapping are two approaches used to specify software visualization. They are applied in, respectively, event-driven and data-driven visualization systems. Yet another approach, data flow mapping, is presented in the paper. However similar to the state mapping, this new method of specification emphasizes dynamic rather then static aspect of the program execution. A comparison of these two approaches is provided in the paper. The basis for discussion is two algorithm animation systems: a data-driven Leonardo system and a data-flow-driven system called Daphnis.