The methods described below can be used to add more details to drawings created by the following visualization methods:

Polytope::VISUAL_GRAPH | Polytope::VISUAL_BOUNDED_GRAPH | TightSpan::VISUAL_BOUNDED_GRAPH

VERTEX_COLORS ([ LPobject ])
Illustrate the behavior of a linear objective function on the polytope. Color the nodes according to the value the objective function takes on the vertices (VERTEX_COLORS)
The spring embedder applies an additional force, which tries to arrange the nodes in the z-axis direction corresponding to the objective function values.
The optional parameter LPobject is introduced for the future use, when it will be possible to store several objective function in a Polytope object.
MIN_MAX_FACE ([ LPobject ])
Illustrate the behavior of a linear objective function on the polytope. The vertices belonging to MINIMAL_FACE and MAXIMAL_FACE are drawn in distinct colors (by default red and yellow).
The spring embedder applies an additional force, which tries to arrange the nodes in the z-axis direction corresponding to the objective function values.
The optional parameter LPobject is introduced for the future use, when it will be possible to store several objective function in a Polytope object.
DIRECTED_GRAPH ([ LPobject ])
Show the growth direction of a linear objective function via arrowed edges.
The optional parameter LPobject is introduced for the future use, when it will be possible to store several objective function in a Polytope object.

Each auxiliary method always returns the visual object it has called with ($this), which makes it easy to build longer method chains of the kind: VISUAL->DIRECTED_GRAPH->VERTEX_COLORS .