Debugging

This section deals with special operators. Those operators haven't any effects on vertices coordinates but only effects on the visual output. Indeed they help user to localize graphical elements (points or segments) on the step in which they are applied. They are optimized to show as much as possible the name of elements. There are two main operators \debug_point and \debug_line. First draws on diagrams the name of vertices currently used. Second is focused on edge. A third operator (\debug) is equivalent to both former ones. It's a shortcut to give simply a maximum information about the current step.
Thoses operators are only used for debugging diagram during its elaboration.