The TouchGraph Link Browser presents a graph which is best conceived as a map.

The map consists of nodes of different colors, which when clicked on bring up the associated web pages. If you hold the mouse over a node, you get a hint describing the contents of what you would find if you were to click on the node.

Nodes are connected by directed edges, which light up when you hold your mouse over the node at their origin. There is no special significance to the direction of the edges, but often they are used to indicate a hierarchical relationship.

Some nodes do not have links associated with them, and thus nothing happens when these nodes are clicked. Such nodes (which I shall call meta-nodes) are useful for displaying information about the nodes that surround them. Meta-nodes allow for the creation of an abstraction-example type of structure, where one finds clusters of related nodes centered around meta nodes. One could also use meta-nodes to create a hierarchy, where link-nodes can be seen as files, and meta-nodes as directories.

I have chosen the convention of coloring the Meta-nodes green, and link-nodes red or blue. Functionally there is no difference between red and blue nodes. The blue color is used to indicate links that are special and worth visiting. The red nodes are standard.

You will see that some nodes have two lines that appear above and below the node name. Such nodes are links to other TouchGraphs, rather then web pages. When you click on such a node, the current graph is replaced by a new graph. To go back to the original graph, click the back button to the right of the zoom bar.

You can browse the graph by using the scroll bars to see regions of the graph that are outside the current display. You can also use the zoom scroll bar if you want to see the whole graph.

While browsing one has the ability to drag nodes. To drag a node, click and drag on a non-selected node. Currently, there is not much use for this feature. It's utility should become more apparent as other features that dynamically change the shape of the graph are added.

If you want to just have some fun dragging nodes around, check out the TouchGraph Layout example, which also allows you to easily add nodes.

You can switch to Editor mode by checking the "edit" check box next to the zoom scroll bar. You can't open links in editor mode, so to switch back to browser mode, click the browse check box.

Editor mode allows you to change the graph by adding and deleting nodes and edges. This is done in the same way as in the TouchGraph Layout example, and you can practice there to get the hang of the interface.

To add a node, select a node, and click and drag from the selected node to an empty space.

To add an edge, select a node, and click and drag from the selected node to another node.

To delete a node, select the node and press the delete key, or right click for the popup menu.

To delete an edge, act as if you are creating a new edge over the existing edge, in the same direction.

You can bring up the popup menu by right clicking.

When you add a new node, or chose to edit a node from the popup menu, you are presented with a node editor dialog. Node name, hint, and color are self-explanatory. The URL can either be a remote URL, or a local URL. Remote URL's begin with "http://" and local URL's are given relative to the location of the applet's jar file. If you enter a local URL, be sure to check the "URL is local" checkbox.

For both remote and local URLs, checking the "URL is local" checkbox causes the page to be opened up in the target frame. Leaving this checkbox unchecked will cause the web page to load in a new window.

The "URL is XML" checkbox indicates that the specified URL is an XML file containing the specification of another TouchGraph Link Browser XML file. When the node is clicked, the specified TouchGraph will replace the current one in the bottom window.

You can bring up the XML viewer window by choosing File, Show XML, from the popup menu.

The XML viewer allows you to save and load graphs. Unfortunately, applets can not directly write files to a remote computer. Thus, to save a file, you have to copy and paste the contents of the XML viewer window into a text editor, and then save this file from the editor. To facilitate this process, a select all button on the XML viewer can get the text ready for copying.

To load a saved XML file, one needs to bring up that file in a text editor, and then copy and paste it into the XML viewer. One can then load this XML file by clicking the update graph with XML button.

Eventually, servlets on the server side will facilitate the saving and loading of the XML files, but for now this process needs to be preformed "manually".