Layout Menu

The Layout menu contains operations for controlling the layout of a graph visualization which is shown in a daVinci base window. There are operations to optimize a layout and to select the layout orientation.

Note: Menus can also be used mouseless with keyboard commands.

Layout Optimization

• Improve All
  This operation starts an algorithm to optimize the layout of the whole graph. 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 View/Graph Info... dialog. Crossing minimization is done by reordering the nodes at each level using a heuristic. Details about the layout algorithm can be found in the concept document. The layout algorithm will never be used after loading a graph, so the user has to do this manually with this menu operation.

• Improve Edges
  Same as Improve All (see above), but the order of the nodes is fixed, i.e. only the layout of the dummy nodes is calculated. For the user this function has the visible effect of a better edge routing, without changing the order of the regular nodes.

• Improve Spacing
  This operation moves all nodes closer together in the graph visualization to take advantage of unused space. The order of nodes is not affected. In daVinci V2.0.2 or higher, empty levels at the top or bottom of the graph (which may be a result of vertical fine-tuning) are also eliminated. Usually, one will use this operation after hiding subgraphs with menu operation Abstraction/Hide Subgraph to get a more compact layout.

• Improve Selected Nodes
  Same as Improve All (see above), but considers only the nodes that are currently selected in the base window and all dummy nodes like in Improve Edges (see above). 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 at 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 quality for the selected nodes.

• Orientation
  The operations in this cascade menu are used to set the orientation of a graph layout. By default, a hierarchical visualization of a graph is draw in top-down direction such that the first level (with the root nodes) is at the upper side of the graph layout and all edges point downwards. Use any of these menus to draw the graph in one of the four orientations. Details about the graph layout can be found in the concept document.
  • Top Down
    Drawing the graph in top-down layout whereby the first level is at the upper side and all edges point downwards. This is the default direction.
  • Bottom Up
    Drawing the graph in bottom-up layout whereby the first level is at the lower side and all edges point upwards.
  • Left to Right
    Drawing the graph in left-to-right layout whereby the first level is at the left side and all edges point to the right.
  • Right to Left
    Drawing the graph in right-to-left layout whereby the first level is at the right side and all edges point to the left.