Programming - Graphical User Interface - Essay Example

12 June 2007 Graphical User Interface: An Overview A Graphical User Interface (GUI) pronounced GOO-ee is a graphical (rather than purely textual) program interface that utilizes the computer’s graphics capabilities to make the program easier to use. It is the most visible part of a computer and is the link between the application software and the end-user. The user interface enables two-way communication by providing feedback to the user, as well as functions for entering data needed by the system (Internet Technology Terms, para. 74). The Graphical User Interface (GUI) is the most popular implementation of a Direct Manipulation Interfaces (DMIs) which presents users with a model of their information space and users can manipulate their information by direct action. Since GUI makes use of “visual objects to implement its model therefore the user can manipulate these objects via a mouse or another pointing device. The User Interface Management Systems (UIMS) are implemented mainly as GUIs so that the interface governs the entire system and not just a single application” (Daniel, Maurice & Thomas, para. 10). The “Graphical User Interface (GUI)” term came into existence because the first interactive user interfaces to computers were not graphical; they were text-and-keyboard oriented alpha-numeric characters and usually comprised of commands. With earlier interactive user interfaces, the computer had dull appearance and had very brief responses. We had to remember the computer commands too. The typical example of user-computer interface is the user interface of DOS operating system which is still used to from Windows operating system. The GUI utilizes the graphical objects to replace and/or supplement alpha-numeric user interfaces. In this way, graphical user interface enhances the end-users and/or application programmers productivity. Well- designed graphical user interface can free the user from learning complex command languages. On the other hand, many users find that they work more effectively with a command-driven interface, especially if they already know the command language (Hoffmann, para.6-8).   Todays major operating systems endow with a graphical user interface. Applications typically use the elements of the GUI that come with the operating system and add their own graphical user interface elements and ideas. The term application is a shorter form of application program. Examples of applications include word processors, database programs, Web browsers, development tools, drawing, paint, and image editing programs, and communication programs. An application program is a program designed to perform a specific function directly for the user or, in some cases, for another application program. The functionality of an application can be programmed perfectly, but if the GUI is hard to figure out or annoying to use, then the program ultimately will be a failure and the end user will likely choose something easier or more convenient. Since making a good GUI is vital to the success of a program, it can be the hardest part of creating a program. When creating an application, many object-oriented tools exist that facilitate writing a graphical user interface. Each GUI element is defined as a class from which you can create object instances for your application. We can code or modify prepackaged methods that an object will use to respond to user stimuli.   The next few sections highlight the different aspects of GUI including its introduction, its elements, practical features and an overview of creating a simple graphical user interface (GUI) that can run commands/operations or that can be used to obtain data from other programs/software such as MATLAB, Google Earth or FAA Integrated Noise Model. Introduction of Graphical User Interface Although the Command Line Interface (CLI) was the first interactive user interface which was derived from the teletypewriters (TTYs) and were used to communicate with mainframes yet the GUI familiar to most of us today in either the Mac or the Windows operating systems and their applications originated at the Xerox Palo Alto Research Laboratory in the late 1970s. Apple used it in their first Macintosh computers called LISA which did not survive. The Amiga by Commodore Business Machines followed Apples example and it introduced a GUI that was both user interface and operating system. Later, Microsoft used many of the same ideas in their first version of the Windows operating system for IBM-compatible PCs. Essential Elements of a Graphical User Interface Since the Graphical User Interface (GUI) is the implementation of a DMI that uses real world based metaphors like electronic spreadsheet to build the users conceptual model of the system, therefore GUI has metaphors for objects familiar in real life, such as the desktop, the view through a window, or the physical layout in a building. The essential elements of a GUI include windows, pull-down menus, buttons, scroll bars, iconic images, wizards, the mouse, pointers, alerts and warnings, dialog boxes, and many more things that havent been invented yet. With the increasing use of multimedia as part of the GUI, sound, voice, motion video, and virtual reality interfaces seem likely to become part of the GUI for many applications. Type of Information Provided by GUI The GUI provides users to the following two type of information. 1. Information about Object 2. Information about action The main focuses of the users’ concentration are different objects. For example, in a word processing application, the user’ focus is on the document which is the object they are manipulating. By focusing users’ attention on objects, GUI’s allow users to concentrate spotlight on their work rather than on how the application is performing the task. Actions modify the properties of an object or manipulate it in some way. Properties are unique characteristics of an object that describe that object. ‘Save’ and ‘Print’ are examples of actions that manipulate objects. An Overview of Creating a Simple Graphical User Interface (GUI) The creation or designing of an effective graphical user interface (GUI) is an important adjunct to application programming. Whether to develop the big software hit or simply to create a computer application for personal or office use, it is essential to have an effective user interface to fully utilize its capabilities. Since the designing of an effective GUI involves both usability testing and creating screen layouts that have informative, intuitive and visually pleasing features, hence it is partially a science and partially an art. Currently most Windows and Mac programmers utilize the more popular and multipurpose graphical user interfaces (GUI). The hallmark of GUI programming lies in its graphical control features, such as toolbar buttons or icons. Contrary to pure text interfaces which accept only keystroke commands, GUIs allow for a variety of input devices (such as a mouse or penlight) for the user to manipulate text and images as visually displayed. Web pages like this one employ a graphical interface, for example, by using image maps to help users navigate the site. Visual Basic, Delphi and C++ are tools commonly used for GUI application development; you can also use Help and HTML processors, numerous database scripting tools, ToolBook, Hypercard, and many other products (Cortes, para. 1-5). Designing Principles An effective and versatile GUI can be design by pursuing the following three basic principles (MATLAB: The Language of Technical Computing, pp. 17-20) ; Simplicity: The simplicity of a GUI design can be obtained by emphasizing on form not on number, minimizing the area of interaction and using group rather than numeric. Consistency : It creates alignment, integrity and harmony among number of demos which makes it easier to move from one demo to an other and hence generate a sense of familiarity among demos. Familiarity: Familiarity and friendliness greatly influence the adoptability of GUI. Familiarity is the value of basing the GUI on a good metaphor. Creating a Simple GUI GUIDE is MATLABs Graphical User Interface Development Environment and primarily a set of set of layout tools including Control Panel, the Property Editor, the Callback Editor, the Alignment Tool, and the Menu Editor. Each tool performs a distinct and can be opened by using their respective commands at the MATLAB prompt. GUIDE also can generates two types of files called FIG-Files and M-files (Creating GUIs with GUIDE, para. 1-7). FIG-files are binary files containing a complete description of all serialized figures (Saving the GUI, para. 1-3) while M-files contains the codes including a framework for the implementation of the callbacks - the functions that execute when users activate a component in the GUI to handle the initialization and launching of the GUI (Creating GUIs with GUIDE, para. 1-7). Creating a GUI using GUIDE can be split into two steps. These two steps are: Design Phase Implementation Phase Design Phase: Design phase comprises of three steps as shown in fig. 1.The best way to approach the task is to start with the ideal design and don’t make compromises too soon. The ideal design may be expensive in terms of development effort or computing yet it is the best practice to achieve the best final designs grow from an idealized initial vision. The first step involves in designing phase is to define the task, often the case in real world examples. The second and third steps are drawing and testing of an idealized GUI design on paper. Paper prototyping is a good exercise for keeping things in perspective. Since there’s no code involved, the idea is to build your entire interface out of paper and try to find out how GUI works. Implementation Phase: After having a complete set of diagrams of the GUI layouts and an exact picture of what functionalities or generally termed as the callbacks are related with each part of the GUI, next comes the codes writing stage. The objective of this stage is to build up the GUI with MATLAB “Handle Graphics”1 components like uicontrols uimenu and axes using the Property Editor as navigation tool to place every Fig.1 building blocks in the right place. GUIDE, MATLABs Graphical User Interface Development Environment, facilitates the creation and manipulation of Handle Graphics objects by simplifying access to the properties of Handle Graphics objects and by placing and arranging the GUI elements on a figure by clicking and dragging with the mouse. The last and final step towards implementing a GUI using GUIDE tools is to test the written codes. This may involves controlling and activating the figures or repositioning the axes and resizing the figures by using the control panel, modifying the callbacks of selected objects by using Callback Editor, aligning selected objects using a collection of vertical and horizontal alignment or distribution push buttons. When all the GUI elements are in place, the GUI is ready to work (MATLAB: The Language of Technical Computing, pp. 17-20). Processing Capabilities of Graphical User Interfaces Since GUI utilizes the graphical along with textual capabilities of computers, hence it gives the users the ability to perform a variety of operations, including, a. What You See Is What You Get (WYSIWYG) editing b. Image Scanning c. Processable Graphics d. Animation and Support for Multimedia e. Porting of documents or files across different applications. Advantages and Disadvantages of Graphical User Interfaces Overall, the advantages of GUIs are: a. Users feel in control of the computer and are not intimidated by it. b. Typical user learning time is short. c. Users get immediate feedback on their actions so mistakes can be detected and corrected very quickly. The disadvantages of GUIs are: a. These interfaces are very processor intensive and memory demanding which imposes a high overhead on the system. Very powerful and expensive processors are needed to adequately support these interfaces. b. Sometimes it longer sequence of steps is necessary to perform certain an operation in a GUI than it is for another type of interface. This can be annoying for experienced users of computers. Works Cited “Internet Technology Terms.” AT&T, National IP Resource Center. May 2007. 12 June, 2007. < http://dedicated.sbcis.sbc.com/NDWS/faq/terms.jsp> “Creating GUIs with GUIDE”. Socsci.umn.edu site. 12 June, 2007. Cortes, Leslie. “Designing a Graphical User Interface.” May 1997. Clinical Information Engines Austin, Texas. 12 June, 2007. Daniel, Marlon. Phillip, Maurice. & Marlon Thomas. “User Interface Design.” Tripod. June. 1999:. 12 June, 2007. “MATLAB: The Language of Technical Computing”. June, 1997. 17-78. Prime Park Way Natick, MA. 12 June, 2007. < http://www-ccs.ucsd.edu/matlab/pdf_doc/matlab/gui/buildgui.pdf> “Saving the GUI”. Socsci.umn.edu site. 12 June, 2007. Read More