Graphics and multimedia:Desktop publishing

Desktop publishing

Most word processors can be used for simple desktop publishing (DTP). You can design a form or a simple magazine using a WP package, and print it out as a master for offset litho or photocopying. The problem is that you cannot normally produce either the wide variety of fonts that are possible with conventional typesetting, or the pictures or other graphics. And WP packages do not give you such a complete control over the final appearance of the printed page.

The advent of low-cost laser printers in 1985 brought typesetting within the reach of the ordinary microcomputer user. These devices can print any kind of text or graphics effects, a capability that was not lost on Apple Computers. Together with a company called Adobe, they brought out the Postscript page description language, which is a piece of software that enables laser printers to produce typesetting fonts and other effects. Another company called Aldus brought out PageMaker, a software package that enabled Apple Macintosh users to 'make up' pages on the screen, i.e. insert text and graphics material and organize its layout ready for printing. With this, the DTP revolution was born.

There are, today, a variety of page make-up packages, running not only on the Macintosh but on other computers as well. The PC is well supported, with a good version of PageMaker as well as Ventura Publisher and other page make-up software.

DTP and typesetting compared

The production of books, magazines, and other published material by conventional typesetting involves the following steps:

1 Authoring the original material, often usmg a WP package.

2 Editing the author's work, and annotating it with instruc­tions to the typesetters on the fonts to be used and the layout of the material.

3 Typesetting the material, i.e. keying it into the typeset­ ting equipment or transferring it electronically from the author's disks, laying it out on the screen, inserting control codes for various fonts, leaving spaces for pic­tures and diagrams, and printing the masters.

4 Pasting onto the master the pictures and diagrams.

5 Printing the final copies using an offset-litho printer.

With desktop publishing, steps 1to 4 can all be done on the same system. The author's original material is imported into a page make-up package, where it can be laid out on the screen, merged electronically with any pictures and graph­ ics, and have suitable fonts inserted. Once the page is right, it can be printed on a laser printer, ready for the offset­ litho.

The advantages of using DTP rather than traditional typesetting are:

• The publication remains under your complete control.

• You can try out different designs and fonts, and see their effects immediately.

• You can produce the final result much more quickly.

• By eliminating the typesetter you can cut costs.

Furthermore, once word processors with full DTP facilities appear (or DTP packages with full word processing facilities appear), the authoring and the page make-up can be done on the same system, and, if required, at the same time. Microsoft's Word for Windows is an example of a WP package with good DTP facilities.

Hypermedia programs

Hypermedia programs are so-called because they span a variety of media, including pictures and music. They enable the user to store, retrieve, and manipulate information in all forms - data, text, image, and sound. Because of the large amount of computer storage space occupied by some of these forms of information - especially image - optical discs may be used in some hypermedia applications.

The term 'information base' could be used of material stored in a hypermedia application. Unlike the material in a database, which is stored in a highly structured form (remember the fields and records of Chapter 6), the material in a hypermedia application can take any form and will be stored in a quite unstructured way. What a hypermedia program does is to allow you to set up links between any item in the information base and any other item, and then to explore relationships by retrieving linked items.

You can visualize the items of information in an infor­mation base as places on a map, and the links between them as roads. As you extract one linked item after another, you are, in effect, taking one of many possible routes through the information. In a sizeable information base, there are a large number of links, resulting in a vast number of possible routes.

Here's one example. In an information base of pictures, a photograph of a building might be linked to a piece of text about a photographer, which might in turn be linked to other photos taken by the same person. It might also be linked to some text on architecture, and then to other photographs of buildings. As well as this, part of the building might be linked to a further close up photograph, or to other photographs of similar features.

To give another example, an information base might consist of a main piece of text - such as a report - and a number of subsidiary notes. Links might be set up between key words and phrases in the main document and material in the notes.

The existence of links attached to a word or phrase, or to a picture or part of a picture, can be indicated on the screen, so prompting you as to the possible routes that can be taken through the material from that point. In the case of the above example of a main document and subsidiary notes, words or phrases with links attached might be highlighted in some way. You select the word that you wish to explore further, usually by clicking on it with the mouse. The linked note then appears in a window on the screen. When you have finished with the note, you can click again to return to your place in the main document.

At the present time, the most well-known hypermedia

program is Hypercard, which runs on the Apple Mac. As its name implies, this program stored information in the form of an electronic card index, each screenful of information occupying a card. An item of information on one card is linked to items on other cards by setting up 'buttons', i.e. symbols on the screen which you click with mouse to move from one item to another linked item.