6.6 Preferences for graphs

A number of graph layout preferences can be set for any tool that uses graphs. You can control settings in the Preferences dialog. To do this:

1. Display the Preferences dialog either by choosing Graph > Preferences... from the graph layout context menu or by one of the methods described in 3.2 Setting preferences.
2. Select the relevant tool in the left side of the Preferences dialog, and select a graph layout tab on the right.

For example, the graph layout preferences for subclasses in the Class Browser are shown in Layout Preferences for the Subclass Graph.

This section describes the options available in the graph layout tabs of the Preference dialogs for any tool that uses graphs.

6.6.1 Altering the depth and breadth of graphs

For large graphs, you may find that you want to alter the maximum depth and breadth in order to simplify the information shown. Each graph pane has its own depth and breadth setting, which is used for all graphs drawn in it. These are available in the Max Expansion panel of the graph layout tabs in the Preferences dialog.

The depth and breadth of a graph are depicted in Depth and breadth of graphs.

Choose a number from the Depth list to change the maximum depth of graphs in a given tool. The depth of a graph is the number of generations of node which are displayed. Most graphs have a default initial depth of 2, which means that you must expand any nodes you want to investigate by expanding them yourself. The default value is 2.

Note that the maximum depth setting is ignored for nodes which you have expanded or collapsed. See 6.3 Expanding and collapsing graphs.

Choose a number from the Breadth list to change the maximum breadth of a given tool. The breadth of a graph is the number of child nodes which are displayed for each parent. If there are more children than can be displayed (the maximum breadth setting is less than the number of children for a given node) an extra node is visible. This node is labeled "…", followed by the number of nodes that are still not displayed. Nonetheless you can expand this node by the Expand Nodes command allowing you to display the additional children without having to alter the maximum breadth setting for the whole graph. By default, the maximum breadth is set to None, so that all the children for a node are displayed, no matter how many there are. An example of this feature is shown in Displaying children hidden by the maximum breadth setting below, where the maximum breadth has been set to 3.

To ensure that all available information is graphed in a given tool, set both the maximum depth and maximum breadth to None.

6.6.2 Displaying different graph layouts

As already mentioned, graphs are laid out from left to right by default, but they can be laid out in other orientations. This can be configured in the Layout panel of the graph layout tab in the Preferences dialog.

Click "Left to Right" to layout a graph from the left of the screen to the right, as shown in Left to right layout. This is the default orientation for every graph in the environment.

Click "Right to Left" to layout a graph from the right of the screen to the left, as shown in Right to left layout.

Click "Top Down" to layout a graph from the top of the screen to the bottom, as shown in Top down layout.

Click "Bottom Up" to layout a graph from the bottom of the screen to the top, as shown in Bottom up layout.