Graphvis/Manual

Working with the system

GraphVis3D system is designed as an applet and is run from command line terminal by running the command

jar gv.jar

The system has a main window and a navigation menu that provides access to uasable operations. You must first create a graph using the Edit menu (or the corresponding keyboard shortcuts), or load an already created graph (menu File-> Open, Ctrl + O) (Fig. 1).

From the File menu you can perform the following operations:

• New - creating a new graph to edit (hotkeys Ctrl + N). The current one will then be lost, so it must first be saved.
• Open (Ctrl + O) - open an existing column for editing. The graphs are saved in a special GML format (extension *. gml), described in a later section. When you select this menu item, the user will be prompted to select from the file system a description file of the graph.
• Save (Ctrl + S) - preservation of the graph in the format of GML. The exact structure of the edited graph is saved.
• Save As - to save (export) of a graph in one of the proposed formats (png, svg, pdf, dot). Exporting to image formats saves the view that the user sees at the moment in the application.
• Print (Ctrl + P) - sending a graph to print. Print options can be changed by the user.
• Exit - Exit the system.

The graph in the system is created and edited in three dimensions. A special feature is that the user can change the point of perspective. While doing this the external view of the graph changes, but not its structure or even the physical coordinates of the vertices in space.

Fig. 2(a) and Fig. 2(b) contain images of the same graph with different points of observation. Navigation in space can be done with the mouse or keyboard using the "hot" keys. Graph preview has two modes: view and edit mode. In the first case, the user can edit the elements of the graph, add new ones, but can change the point of observation. In the second, the contrary.

View menu provides the following functionality:

• Zoom, "Zoom in", "Zoom out", "100%", "Page Width", "local magnification" - control the scale of the image.
• Mode - switching between browsing and editing the graph.
• Graph Analysis - see more possibilities.

Editing the graph

The GraphVis3D system allows you to visualize the following graph elements: vertices, edges between vertices, the labels on vertices and edges. For images of vertices several geometric shapes are used. Point (sphere of minimum radius), cube (or an arbitrary rectangular box), cylinder, cone.

For each node type you can set and edit the size, color fill. These parameters are set separately for each vertex. Thus it is possible to create several types of vertices, visually similar to each other, but different text labels.

Edges (arcs) of a graph can be represented by one of the following: lines joining the vertices of a graph, broken line, defined by control points, smooth curves passing through a set of control points (for the three-dimensional splines are used). Options for type of arc, its color, thickness, the presence of the arrow (directed graphs) are edited for each vertex separately.

It is also possible to mass-edit system objects.

For simplicity and ease of editing, any system objects are edited by mouse, using the familiar drag & drop technology. Thus, it is possible, for example, to "drag" elements of the graph in space, create or delete control points on the edges, change the position of labels relative to their tops.

Label - a text description of the item count. In the described application, tags can be created for the vertices and edges. The label has a number of editable attributes: label text (possibly a numeric value), color, size, font. You can change the label position relative to its parent. Labels on the edges can be used to build weighted graphs.

Editing the graph by using the mouse (drag & drop), keyboard (with hot keys) or the Edit menu. From this menu I have available two important functions:

• Re-do (Ctrl + Y) - repeat the last undone operation.
• Undo (Ctrl + Z) - undo the last performed operation.

The system keeps track of all transactions that change the internal structure of the graph. With the help of these commands any erroneously executed command can undo the action (such as accidentally deleting an element of the graph). By default, the recorded history is the last 25 commands. This number can be changed while editing the current style (see Styles).

Fig. 3 illustrates some features of the system for editing the elements of the graph.