|MainUser InterfaceLayout Menu
The Layout menu contains operations for controlling the layout
of a graph visualization which is shown in the graph area of a
There are operations to
optimize a layout
select the layout orientation.
menu operations can also be invoked without the mouse by using
This operation starts an algorithm to optimize the layout of the
The most important task of the layout algorithm is to reduce
the number of crossings between edges.
Reducing edge crossings is a technique to clarify a graph layout.
The current number of crossings is displayed in the
Edge Crossing reduction is done by reordering the nodes at each
level using a heuristical approach.
Details about the layout algorithm
can be found in the concepts document.
Because crossing reduction is an expensive operation, the layout
algorithm will not be used immediately after loading a graph.
So the user has to do this manually with this menu operation.
Same as "Improve All" (see above), but the order of the nodes
is fixed here, so only the position of the invisible dummy nodes
(used to fill long span edges) is calculated.
For the user, this function has the effect of better edge routing,
without changing the order of the regular nodes.
even if the order of regular nodes is fixed here, their
absolute position may change.
This layout operation moves all nodes closer together in the
graph visualization to take advantage of unused space.
The order of nodes is not affected.
Usually, one will use this operation after hiding subgraphs
with menu operation
to get a more compact layout.
Improve Selected Nodes
Same as "Improve All" (see above), but this operation optimizes
the position of the nodes that are currently selected in the base
window and all of their dummy nodes.
The advantage of a local layout optimization is that the resulting
visualization may be better for the selected nodes, because the
surrounding nodes which are not visible this time must not be
taken into account.
The disadvantage is that the layout of the other nodes may be
getting worse after using this operation.
So use this operation when you are not interested in a good
overall layout, but want to get the best result for the selected
Controlling the Layout Orientation
The operations in this cascade menu are used to set the general
orientation of a graph layout.
By default, a hierarchical visualization of a graph is drawn in
top-down direction so the first level (with the root nodes)
is at the upper side of the graph layout and all edges point
Use any of these menus to draw the graph in one of the four
Details about the graph layout
can be found in the concept chapter.
To draw the graph with a top-down layout where the first level
is at the upper side and all edges point downwards.
This is the default direction.
To draw the graph with a bottom-up layout where the first level
is at the lower side and all edges point upwards.
Left to Right
To draw the graph with a left-to-right layout where the first level
is at the left side and all edges point to the right.
Right to Left
To draw the graph with a right-to-left layout where the first level
is at the right side and all edges point to the left.