Apps similar to Xdot include KGraphViewer, which is free and open source. Other options are ZGRViewer. Between them they cover Linux, Mac and Windows.
KGraphViewer is a Graphviz DOT graph file viewer, aimed to replace the other outdated Graphviz tools. Graphs are commonly used in scientific domains and particularly in computer science.
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ZGRViewer is a graph visualizer implemented in Java and based upon the Zoomable Visual Transformation Machine. It is specifically aimed at displaying graphs expressed using the DOT language from AT&T GraphViz and processed by programs dot, neato or others such as twopi.
