qvge

qvge (Qt Visual Graph Editor) is an open-source, cross-platform desktop application for interactively drawing and editing two-dimensional graphs. It is developed by Ars Masiuk as a spare-time free-software project and released under the MIT license. Written in C++ (C++11) on top of the Qt 5 framework, it builds and runs on Windows, Linux, macOS, and Cygwin using GCC, Clang, MinGW, or Visual Studio. Its stated aim is deliberately narrow: to let users create and lay out modest graphs (on the order of a thousand-plus nodes and edges) in a simple, direct way, rather than to serve as a large-scale network-analysis or scientific-computing platform.

The data model is a property graph of nodes and edges that can be directed, undirected, or mixed. Every element carries visual attributes such as shape, size, color, and label, and users may attach arbitrary custom attributes as well. The editor adds features like node ports, polygonal edge routing, and search across elements and attributes. Layout is not computed natively; qvge shells out to Graphviz (Graphviz) engines dot, neato, fdp, sfdp, and circo, and, when built with the Open Graph Drawing Framework (OGDF), gains additional algorithms including FMMM, Sugiyama, planar, circular, balloon, and Davidson-Harel.

For interchange, qvge reads and writes several standard formats, which makes it useful as a lightweight visual bridge in a format-conversion workflow. It uses XGR as its native persistence format, and supports GraphML (GraphML), GEXF (GEXF, limited to a common subset that excludes clusters and dynamic properties), GML (GML), and Graphviz DOT (DOT). DOT and GML reading are delegated to Graphviz/Boost or OGDF, while writing is handled internally. Rendered output can be exported to PDF, SVG, and raster images (PNG, BMP, JPG, TIFF).

The project positions itself explicitly as complementary to, not a replacement for, heavier tools: the author names Gephi (Gephi), yEd (yEd), Inkscape, and Dia as software with different scope, and states qvge is neither a big-data analysis tool nor a mathematics application. Its strengths are a low barrier to entry, clean interactive editing of small annotated graphs, and interoperability with common XML-based graph formats; its limitations are the absence of built-in analytics, weak handling of very large or highly dynamic graphs, and dependence on external libraries for some import paths and layouts.