Text B. Interface with menus

Improvements arrived with the addition of menus and the use of the arrow keys to move around the screen. This is much better than having to type in all the commands.

The example to the right is of a old bulletin board communications program. People would post messages and reply to other people's messages.

Notice the list of commands in the pop-up menu in the center. You would use the arrow keys to move up and down the list and then press the Enter key to execute the command. Various menus were usually available by using the ALT key in combination with a letter or number key.

Graphical Interface

A graphical user interface (GUI - sometimes pronounced GOO-ee) uses pictures to make it easier for the user. It is user friendly.

The use of drop-down menus, windows, buttons, and icons was first successfully marketed by Apple on the Macintosh computer. These ideas are now as standard for graphical interfaces as door knobs are for doors.

Computer graphics are pictures and drawings produced by computer. There are two main categories:

Raster graphics, or bitmaps, are stored as a collection of pixels. The sharpness of an image depends on the density of pixels, or resolution. For example, text or pictures that are scaled up – that is, made bigger – may show jagged edges, paint and photo – editing programs like Adobe Photoshop focus on the manipulation of bitmaps. Popular raster formats are JPEG, GIF and TIFF.

Vector graphics represent images through the use of geometric objects, such as lines, curves and polygons, based on mathematical equations. They can be changed or scaled without losing quality. Vector data can be handled by drawing programs like Adobe Illustrator, Corel Draw or Macromedia Freehand. EPS is the most popular file format for exchanging vector drawings.

Almost all computer users use some form of graphics. Home users and professional artists use image-editing programs to manipulate images. For example, you can add filters (special effects) to your favourite photos, or you can composite images. Compositing is combining parts of different images to create a single image. Graphic artists and designers use drawing programs to create freehand drawings and illustrations for books or for the Web. Businesspeople use presentation graphics to make information more interesting visually – graphs and diagrams can be more effective ways of communicating with clients than lists of figures. Electrical engineers use CAD (Computer Aided Design) software to develop, model and test car designs before the actual parts are made. This can save a lot of time and money. CAD is also used in the aerospace, architecture and industrial sector to design everything from airplanes and buildings to consumer products. Designers start a project by making a wireframe, a representation showing the outlines of all edges in a transparent drawing. They then specify and fill the surfaces to give the appearance of a 3-D solid object with volume. This is known as solid modeling. Next, they add paint, colour and filters to achieve the desired “look and feel”: this is called texturing the object. Finally, they render the object to make it look real. Rendering includes lighting and shading as well as effects that simulate shadows and reflections.

Computer art, or digital art, is used in adverts and TV programmes. Artists and scientists use special graphic applets to create amazing fractals. Fractals are geometrical patterns that are repeated at small scales to generate irregular shapes, some of which describe objects from nature. Government agencies use GIS (Geographic Information Systems) to understand geographical data and then plan the use of land or predict natural disasters. Cartographers use GIS to make detailed maps. Animators use computer animation software to create animated cartoons or add effects in movies and video games.