FIG. 1 shows examples of hypertext and hypermedia documents and links associating data objects in the documents to other data objects.
解答例
Hypermedia document 10 includes hypertext 20, an image icon at 22, a sound icon at 24 and more hypertext 26.
FIG. 1 shows hypermedia document 10 substantially as it would appear on a user's display screen.
The user is able to select, or "click" on icons and text on a display screen by using an input device, such as a mouse, in a manner well-known in the art.
When the user clicks on the phrase "hypermedia," software running on the user's computer obtains the link associated with the phrase, symbolically shown by arrow 30, to access hypermedia document 14.
Hypermedia document 14 is retrieved and displayed on the user's display screen.
Thus, the user is presented with more information on the phrase "hypermedia."
The mechanism for specifying and locating a linked object such as hypermedia document 14 is an HTML "element" that includes an object address in the format of a Uniform Resource Locator (URL).
Similarly, additional hypertext 26 can be selected by the user to access hypertext document 12 via link 32 as shown in FIG. 1.
If the user selects additional hypertext 26, then the text for hypertext document 12 is displayed on the user screen.
Note that hypertext document 12, itself, has hypertext at 28.
Thus, the user can click on the phrase "hypermedia" while viewing document 12 to access hypermedia document 14 in a manner similar to that discussed above.
Documents, and other data objects, can be referenced by many links from many different source documents.
FIG. 1 shows document 14 serving as a target link for both documents 10 and 12.
A distributed hypertext or hypermedia document typically has many links within it that specify many different data objects located in computers at different geographical locations connected by a network.
Hypermedia document 10 includes image icon 22 with a link to image 16.
One method of viewing images is to include an icon, or other indicator, within the text.
Typically, the indicator is a very small image and may be a scaled down version of the full image.
The indicator may be shown embedded within the text when the text is displayed on the display screen.
The user may select the indicator to obtain the full image.
When the user clicks on image icon 22 browser software executing on the user's computer system retrieves the corresponding full image, e.g., a bit map, and displays it by using external software called a "viewer."
This results in the full image, represented by image 16, being displayed on the screen.
An example of a browser program is the National Center for Supercomputing Application's (NCSA) Mosaic software developed by the University of Illinois at Urbana/Champaign, Ill.
Another example is "Cello" available on the Internet at http://www.law.cornell.edu/.
Many viewers exist that handle various file formats such as ".TIF," ".GIF," formats.
When a browser program invokes a viewer program, the viewer is launched as a separate process.
The view displays the full image in a separate "window" (in a windowing environment) or on a separate screen.
This means that the browser program is no longer active while the viewer is active.
By using indicators to act as place holders for full images that are retrieved and displayed only when a user selects the indicator, data traffic over the network is reduced.
Also, since the retrieval and display of large images may require several seconds or more of transfer time the user does not have to wait to have images transferred that are of no interest to the user.
