Icon (computing)

Standardized electrical device symbols

A series of recurring computer icons are taken from the broader field of standardized symbols used across a wide range of electrical equipment. Examples of these are the power symbol and the USB icon, which are found on a wide variety of electronic devices. The standardization of electronic icons is an important safety-feature on all types of electronics, enabling a user to more easily navigate an unfamiliar system. As a subset of electronic devices, computer systems and mobile devices use many of the same icons; they are corporated into the design of both the computer hardware and on the software. On the hardware, these icons identify the functionality of specific buttons and plugs.^[8] In the software, they provide a link into the customizable settings.^[9]

System warning icons also belong to the broader area of ISO standard warning signs. These warning icons, first designed to regulate automobile traffic in the early 1900s, have become standardized and widely understood by users without the necessity of further verbal explanations. In designing software operating systems, different companies have incorporated and defined these standard symbols as part of their graphical user interface. For example, the Microsoft MSDN^[10] defines the standard icon use of error, warning, information and question mark icons as part of their software development guidelines.^[11]

Different organizations are actively involved in standardizing these icons, as well as providing guidelines for their creation and use. The International Electrotechnical Commission (IEC) has defined "Graphical symbols for use on equipment", published as IEC 417, a document which displays IEC standardized icons. Another organization invested in the promotion of effective icon usage is the ICT (information and communications technologies), which has published guidelines for the creation and use of icons.^[2] Many of these icons are available on the Internet, either to purchase or as freeware to incorporate into new software.

Metaphorical icons

An icon is a signifier pointing to the signified. Easily comprehendible icons will make use of familiar visual metaphors directly connected to the signified: actions the icon initiate or the content that would be revealed. Metaphors, metonymy and synecdoche are used to encode the meaning in an icon system.

The signified can have multiple natures: virtual objects such as files and applications, actions within a system or an application (e.g. snap a picture, delete, rewind, connect/disconnect etc...), action in the physical world (e.g. print, eject DVD, change volume or brightness etc...) as well as physical objects (e.g. monitor, compact disk, mouse, printer etc...).

The Desktop metaphor

A subgroup of the more visually rich icons is based on objects lifted from a 1970 physical office space and desktop environment. It includes the basic icons used for a file, file folder, trashcan, inbox, together with the spatial real estate of the screen, i.e. the electronic desktop. This model originally enabled users, familiar with common office practices and functions, to intuitively navigate the computer desktop and system. (Desktop Metaphor, pg 2). The icons stand for objects or functions accessible on the system and enable the user to do tasks common to an office space. These desktop computer icons developed over several decades; data files in the 1950s, the hierarchical storage system (i.e. the file folder and filing cabinet) in the 1960s, and finally the desktop metaphor itself (including the trashcan) in the 1970s.^[12]

David Canfield Smith associated the term "icon" with computing in his 1975 PhD thesis "Pygmalion: A Creative Programming Environment".^[13][14] He envisioned a scenario in which "visual entities", called icons, could execute lines of programming code, and save the operation for later re-execution.^[15] Smith later served as one of the principal designers of the Xerox Star, which became the first commercially available personal computing system based on the desktop metaphor when it was released in 1981. "The icons on [the desktop] are visible concrete embodiments of the corresponding physical objects."^[16] The desktop and icons displayed in this first desktop model are easily recognizable by users several decades later, and display the main components of the desktop metaphor GUI.

This model of the desktop metaphor has been adopted by most personal computing systems in the last decades of the 20th century; it remains popular as a "simple intuitive navigation by single user on single system."^[12] It is only at the beginning of the 21st century that personal computing is evolving a new metaphor based on Internet connectivity and teams of users, cloud computing. In this new model, data and tools are no longer stored on the single system, instead they are stored someplace else, "in the cloud". The cloud metaphor is replacing the desktop model; it remains to be seen how many of the common desktop icons (file, file folder, trashcan, inbox, filing cabinet) find a place in this new metaphor.

Brand icons for commercial software

A further type of computer icon is more related to the brand identity of the software programs available on the computer system. These brand icons are bundled with their product and installed on a system with the software. They function in the same way as the hyperlink icons described above, representing functionality accessible on the system and providing links to either a software program or data file. Over and beyond this, they act as a company identifier and advertiser for the software or company.^[17]

Because these company and program logos represent the company and product itself, much attention is given to their design, done frequently by commercial artists. To regulate the use of these brand icons, they are trademark registered and are considered part of the company's intellectual property.

In closed systems such as iOS and Android, the use of icons is to a degree regulated or guided^[18] to create a sense of consistency in the UI.

Overlay icons

On some GUI systems (e.g. Windows), on an icon which represents an object (e.g. a file) a certain additional subsystem can add a smaller secondary icon, laid over the primary icon and usually positioned in one of its corners, to indicate the status of the object which is represented with the primary icon. For instance, the subsystem for locking files can add a "padlock" overlay icon on an icon which represents a file in order to indicate that the file is locked.

Tools

Icons underwent a change in appearance from the early 8-bit pixel art used pre-2000 to a more photorealistic appearance featuring effects such as softening, sharpening, edge enhancement, a glossy or glass-like appearance, or drop shadows which are rendered with an alpha channel.

Icon editors used on these early platforms usually contain a rudimentary raster image editor capable of modifying images of an icon pixel by pixel, by using simple drawing tools, or by applying simple image filters. Professional icon designers seldom modify icons inside an icon editor and use a more advanced drawing or 3D modeling application instead.

The main function performed by an icon editor is generation of icons from images. An icon editor resamples a source image to the resolution and color depth required for an icon. Other functions performed by icon editors are icon extraction from executable files (exe, dll), creation of icon libraries, or saving individual images of an icon.

All icon editors can make icons for system files (folders, text files, etc.), and for web pages. These have a file extension of .ICO for Windows and web pages or .ICNS for the Macintosh. If the editor can also make a cursor, the image can be saved with a file extension of .CUR or .ANI for both Windows and the Macintosh. Using a new icon is simply a matter of moving the image into the correct file folder and using the system tools to select the icon. In Windows XP you could go to My Computer, open Tools on the explorer window, choose Folder Options, then File Types, select a file type, click on Advanced and select an icon to be associated with that file type.

Developers also use icon editors to make icons for specific program files. Assignment of an icon to a newly created program is usually done within the Integrated Development Environment used to develop that program. However, if one is creating an application in the Windows API he or she can simply add a line to the program's resource script before compilation. Many icon editors can copy a unique icon from a program file for editing. Only a few can assign an icon to a program file, a much more difficult task. There are also resource editing tools that allow users to extract or replace icons embedded in Windows executable files, such as Resource Hacker or Resource Tuner.

Simple icon editors and image-to-icon converters are also available online as web applications.

List of tools

This is a list of notable computer icon software.

• Axialis IconWorkshop – Supports both Windows and Mac icons. (Commercial, Windows)
• IcoFX – Icon editor supporting Windows Vista and Macintosh icons with PNG compression (Commercial, Windows)
• IconBuilder – Plug-in for Photoshop; focused on Mac. (Commercial, Windows/Mac)
• Microangelo Toolset – a set of tools (Studio, Explorer, Librarian, Animator, On Display) for editing Windows icons and cursors. (Commercial, Windows)
• Microsoft Visual Studio - can author ICO/CUR files but cannot edit 32-bit icon frames with 8-bit transparency.^[20] (Commercial, Windows)

The following is a list of raster graphic applications capable of creating and editing icons:

• GIMP – Image Editor Supports reading and writing Windows ICO/CUR/ANI files and PNG files that can be converted to Mac .icns files. (Open Source, Free Software, Multi-Platform)
• ImageMagick and GraphicsMagick – Command Line image conversion & generation that can be used to create Windows ICO files and PNG files that can be converted to Mac .ICNS files. (Open Source, Free Software, Multi-Platform)
• IrfanView – Support converting graphic file formats into Windows ICO files. (Proprietary, free for non-commercial use, Windows)
• ResEdit – Supports creating classic Mac OS icon resources. (Proprietary, Discontinued, Classic Mac OS)