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### 2.12 The Callgraph View

The callgraph view plays a role similar the callgraph browser. They display the same information about entities, but in two different ways: the callgraph view displays the information in a tree, easily navigable and perhaps easier to manipulate when lots of entities are involved; the callgraph browser displays the information as graphical boxes that can be manipulated on the screen, and is best suited to generate a diagram that can be later exported to your own documents.

This callgraph view is used to display the information about what subprograms are called by a given entity, and, opposite, what entities are calling a given entity.

Some references might be reported with an additional " (dispatching)" text. In such a case, this indicates that the call to the entity is not explicit in the sources, but could occur through dynamic dispatching. This of course depends on what arguments are passed to the caller at run time, and it is possible that the subprogram is in fact never dispatched to.

This view is automatically displayed when you select one of the contextual menus `... calls` and `... is called by`. Every time you select one of these menus, a new view is opened to display that entity.

Whenever you expand a node from the tree by clicking on the small expander arrow on the left of the line, further callgraph information is computed for the selected entity, which makes it very easy to get information for a full callgraph tree.

Closing and expanding a node again will recompute the callgraph for the entity.

On the right side of the main tree, a list displays the locations of calls for the selected entity. Clicking on entries in this list opens editors showing the corresponding location.

The Callgraph View supports keyboard navigation: `Up` and `Down` keys navigate between listed locations, `Left` collapses the current level, `Right` expands the current level, and `Return` jumps to the currently selected location.

The callgraph view is automatically saved in the desktop, and restored the next time you restart GPS. However, the information displayed in these might no longer be accurate at this stage, since it shows the status of the callgraph during the last GPS session.

Left-clicking on a line in the Call Tree brings up a contextual menu with the following entries:

Collapse all
  Collapse all the entities in the Callgraph View.
Remove entity
  Remove the selected entity from the Callgraph View.
Clear Call Trees
  Remove all entries from the Callgraph View.