FlowCanvas is an interactive Gtkmm/Gnomecanvasmm widget for graph-based
interfaces (patchers, modular synthesizers, finite state automata,
interactive graphs, etc).
FlowCanvas provides classes for "Modules" (boxes with "Ports"), Ellipses,
and Connections (lines that connect either Ports or Ellipses). The user
can rearrange items, or FlowCanvas can automatically arrange items using
GraphViz. Connections can be made by the user one at a time with the
mouse, or in groups using the mouse and keyboard.
For more information, see <http://drobilla.net/software/flowcanvas>.
-- David Robillard <email@example.com>