Ultimately, diagrams are displayed on the user screen
within
views that can occupy an entire window or part
of one.
Each view has its own zoom level and displays a part
of the diagram. The user can zoom and pan within a view to focus on
regions of interest. At any moment, multiple views can be used with
a single diagram as if the user had several cameras to give different
points of view, see the following figure.
The overview is a special use of the multiple-view concept:
it is a view that displays the entire diagram in miniature, overlaid
with a navigation rectangle that represents the visible part of the
diagram in the main view. By moving and resizing this rectangle, the
user can easily zoom and pan the main view.
The diagram’s graphical objects can be grouped
in
layers that control their display priority. You
may, for example, decide that the nodes and links are in a higher
layer than the background map: they are always displayed on top of
the map. You may also decide that labels are always displayed on top
of everything by grouping them in the highest layer. Layers can also
be set visible or invisible—for each view—so that you
can temporarily hide an entire group of symbols or a background map.
Finally, JViews Diagrammer offers three alternative
views of a diagram’s
data model: a table view, a tree view, and a
property sheet.
In the table view, the properties of the nodes and links
are displayed as a Swing JTable that can be edited in an application.
In the tree view, the data model is displayed as a Swing JTree, which
is useful for selecting objects—the Data Model panel in the
Designer uses this view. For both of these, see the following figure.
In a property sheet, a simple list of properties is displayed—the
optional Styling Properties panel in the Designer displays this view.