Characteristics of the Graphical User Interface
Sophisticated Visual Presentation
Visual presentation is the visual aspect of the interface. It is what people see on the screen. The sophistication of a graphical system permits displaying lines, including drawings and icons. It also permits the displaying of a variety of character fonts, including different sizes and styles.
The meaningful interface elements visually presented to the user in a graphical system include windows (primary, secondary, or dialog boxes), menus (menu bar, pulldown, pop-up, cascading), icons to represent objects such as programs or files, assorted screen-based controls (text boxes, list boxes, combination boxes, settings, scroll bars, and buttons), and a mouse pointer and cursor. The objective is to reflect visually on the screen the real world of the user as realistically, meaningfully, simply, and clearly as possible.
To identify a proposed action is commonly referred to as pick, the signal to perform an action as click.
The primary mechanism for performing this pick-and-click is most often the mouse and its buttons and the secondary mechanism for performing these selection actions is the keyboard.
Restricted Set of Interface Options
The array of alternatives available to the user is what is presented on the screen or what may be retrieved through what is presented on the screen, nothing less, and nothing more. This concept fostered the acronym WYSIWYG.
Visualization is a cognitive process that allows people to understand information that is difficult to perceive, because it is either too voluminous or too abstract.
The goal is not necessarily to reproduce a realistic graphical image, but to produce one that conveys the most relevant information. Effective visualizations can facilitate mental insights, increase productivity, and foster faster and more accurate use of data.
A graphical system consists of objects and actions. Objects are what people see on the screen as a single unit.
Objects can be composed of subobjects .For example, an object may be a document and its subobjects may be a paragraph, sentence, word, and letter.
Objects are divided into three meaningful classes as Data objects, which present information, container objects to hold other objects and Device objects, represent physical objects in the real world.
Objects can exist within the context of other objects, and one object may affect the way another object appears or behaves. These relationships are called collections, constraints, composites, and containers.
Properties or Attributes of Objects : Properties are the unique characteristics of an object. Properties help to describe an object and can be changed by users.
Actions : People take actions on objects. They manipulate objects in specific ways (commands) or modify the properties of objects (property or attribute specification).
The following is a typical property/attribute specification sequence: o The user selects an object—for example, several words of text.
The user then selects an action to apply to that object, such as the action BOLD.
The selected words are made bold and will remain bold until selected and changed again.
Application versus Object or Data Orientation An application-oriented approach takes an action: object approach, like this:
Action> 1. An application is opened (for example, word processing). Object> 2. A file or other object selected (for example, a memo).
An object-oriented object:action approach does this: Object> 1. An object is chosen (a memo).
Action> 2. An application is selected (word processing).
Views : Views are ways of looking at an object’s information. IBM’s SAA CUA describes four kinds of views: composed, contents, settings, and help.
Use of Recognition Memory
Continuous visibility of objects and actions encourages to eliminate “out of sight, out of mind” problem
Concurrent Performance of Functions
Graphic systems may do two or more things at one time. Multiple programs may run simultaneously.
It may process background tasks (cooperative multitasking) or preemptive multitasking.
Data may also be transferred between programs. It may be temporarily stored on a “clipboard” for later transfer or be automatically swapped between programs.
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