Glossary » Computer Graphics

indication

showing what item would be selected if the user were to click. Analogous to hiliting the current selection, indication highlights as the user mouses over items, helping the user to accurately make selections.

information visualization

the study of how to effectively present information visually. Much of the work in this field focuses on creating innovative graphical displays for complicated datasets, such as census results, scientific data, and databases. An example problem would be deciding how…

interlacing

displaying images by drawing only a partial image first, consisting of alternate lines, or every 3rd or 4th line, then filling in the remaining lines progressively. When images are displayed slowly, such as large gifs slowly downloading off the internet,…

inverse video

or reverse video; the use of inverted graphics (black for white and white for black) to indicated selected regions, usually used to refer to inverted text on alphanumeric terminals, but also inverted menu items and icons that are selected.

marquee

1. (computer graphics) the dotted-line that appears around drawings when they are selected in drawing programs. When animated, a marquee is often referred to as the “marching ants”.

2. (graphic design) a hilited area, usually the focal point of a…

panning

an alternative to scrolling for moving the viewed area within a window – the user drags the view (and usually the pointer changes to a flat hand) in 2 dimensions (instead of the 1-dimensional scrollbar).

In video, panning refers to…

perspective wall

a way of densely displaying large amounts of information by placing information on a flat plane which is tilted into the screen so that it shrinks back toward infinity. More important items (such as upcoming dates on a calendar) can…

raster display

the standard technology for computer monitors that display images on a grid of pixels, allowing the computer to light up any individual pixel easily, and enabling color displays by having individual red, green, and blue (RGB) phosphors at each pixel…

resize handle

a small box that appears at each of the corners of a selected object (and sometimes at the sides also) that can be dragged to alter the size of the object.

rollovers

actions that occur as a user moves a pointer over objects, such as the hiliting of buttons as a user moves over them, in order to indicate that they are clickable, and also sometimes used to provide additional information (such…

rubberbanding

when creating or resizing graphics, such as a rectangle or oval, the way it stretches, like a rubberband, to follow the pointer as you drag it.

scientific visualization

the graphical representation of complex physical phenomena in order to assist scientific investigation and to make inferences that aren’t apparent in numerical form. Typical examples include processing of satellite photographs and 3D representations of molecules and fluids to examine their…

screen font

a font designed for legibility when displayed on a computer screen (or, for example, on a television screen) as opposed to a “printer font”, which is optimized for printing. Screen fonts need to be designed for clarity on the relatively…

seizure disorder

in some types of epilepsy, a seizure can result from the presentation of a rapidly-varying stimulus, such as flashing lights and repetitive sounds. Thus, interfaces should avoid strobe effects, blinking effects, and repetitive noises. In most interfaces, these are likely…

simulator sickness

virtual environment sickness or cybersickness; an adverse reaction to immersion in a 3D virtual environment characterized by symptoms of nausea, motion sickness, disorientation, and loss of control over movement. This reaction is typically explained by sensory conflict theory, the idea…

slow in and slow out

in animation, the acceleration and deceleration of action, i.e. the way that an action begins slowly, moves quickly through the main action, and then slows down as it comes to a stop rather than moving linearly from one position to…

snapping / gravity

a graphics input technique – when people draw or drag objects near a gridline, guideline, or another object, the object they are drawing or moving automatically jumps into alignment (snaps) as soon as it gets close, as if the guideline…

sprite

an operating system capability that allows programmers to easily create independent graphical objects (“sprites”) that can move around the screen. A sprite automatically handles redrawing areas of the screen that it crosses over, saving the programmer from worrying about updating…

squash and stretch

in animation, elastic distortions of shapes during motion, especially of living creatures, to reflect the stretch of elastic body tissue, such as cheeks stretching and bulging during chewing. These distortions may be exaggerated to clarify an action, but the common…

staging

in animation, the choice of composition, viewpoint, and acting to communicate most effectively without confusion, distracting details, or tradeoffs that sacrifice clarity.

stereopsis

the perception of depth based on the differences in images that reach the 2 eyes.

storyboard

a series of illustrations that represent a process, such as the steps of interacting with a computer or frames from an animation or movie. Storyboards are useful for presentations, such as with focus groups, and for checking that the steps…

struts and springs

a graphical way of representing layout constraints, used in some UIMS to handle the layout specifications for widgets. Struts and springs allow a programmer to specify minimum and maximum widths, proportions of the screen, alignment, and so forth.

tele-embodiment

especially in virtual reality systems, taking on a specific form when communicating with someone. The form may be a representation of your own physical body, someone else, a fantasy creature, or an abstract entity.

tethered viewpoint

a virtual reality or immersive environment where people’s actions control a remote representation of themselves, an avatar, or a device, that they can watch and control within the environment, as opposed to thinking of themselves as directly inside the environment.…