Professional Graphics Dictionary
A B C D E F G H I J K L M O P R S T V Y Z
3D
Three-dimensional
3D-DDI
3D device driver interface, software interface (3D-API) from Microsoft, higher level 3D-APIs like OpenGL and 3DR may be implemented in Windows 95
3DR
3D software interface (3D-API) from Intel, supporting Microsoft's GDI DDI, DCI and 3D-DDI
AutoDesk Device Interface
Alpha blending
Creating transparent materials with the help of additional information for each pixel.
Analog
Continuously varying electronic signal to reproduce information. Compare digital.
Analog Display
Monitor that uses variable color control voltages to display a very large number of colors but requires very few inputs.
ANSI
American National Standards Institute.
Anti-aliasing
Interpolating the colors of neighboring pixels in order to avoid the 'pixel look' of an image.
Artifacts
Blurred or "blocky" portions of degraded image quality in a digital video.
ASCII
American Standards Committee on Information Interchange. A standard used by IBM and compatible computers to represent numbers and characters in binary form.
Required capacity for the data volume and transmission rate.
BIOS
Stands for Basic Input-Output System. Code in your computer's ROM (Read Only Memory) that provides the power-on self test and other operating functions.
Bits per pixel
Number of bits used to represent the color information of a pixel.
Blitter
Fast memory transfer in the graphics board without using the CPU, e.g. used for moving parts of the invisible screen.
BMP (Windows Bitmap)
This format enables Microsoft Windows to display images on devices with similar capabilities in a consistent way. Save pictures in this format if you wish to continue to process them later under Windows.
BNC connector
Standardized connector with a bayonet socket, used for connecting a graphics board to a monitor with separate R(ed), G(reen) and B(lue) inputs.
Booting/Booting Up
Starting the computer. There are two types. Warm booting is accomplished by simultaneously pressing the CTRL/ALT/DEL keys and can occur only when the computer is running. A cold boot requires activation of the ON/OFF switch.
Brightness
Brightness of an image is determined by the amount of light emitted by it. No light (black) therefore means 'no brightness', whereas pure white light means 'maximum brightness'.
Burst mode
Fastest data transfer mode in which a large burst of pure data is transferred in one block.
Bus master
PCI bus slots must have bus master capability. This means PCI extension boards may move data very fast via the PCI bus without using the CPU (similar to Direct Memory Access).
Bus system
System of parallel data lines to transfer information between individual system components, especially to expansion boards (e.g. PCI bus).
IBM Color Graphics Adapter, one of the first color graphics standards. Either 320x200 pixels with four colors or 640x200 pixels with two colors can be displayed.
Chrominance
Portion of a video signal which corresponds to color values and includes information about hue and saturation. This color component essentially complements the brightness or luminance component of a color video picture.
Clipping
Limiting the drawing area to any rectangular area by cutting its edges.
Color Display
Type of monitor capable of displaying information in color. It is often called an RGB (red, green, blue) monitor, referring to the signals needed to drive it.
Contrast
The contrast of an image is the difference between light and dark. A contrast-intensive image is one in which contains strong transitions from light to dark. A contrast-weak image contains transitions that are hardly noticeable.
CPU
Central Processing Unit, which is the main processor chip of a computer, e.g. Pentium.
converts digital input signal to analog output signal, e.g. image data in the display memory of the graphics board is converted to video signal for the monitor to display.
DDC (Display Data Channel)
The VESA Display Data Channel provides a serial data channnel
between the monitor and the graphics card - if both, monitor and
graphics card support DDC and the monitor data cable includes the
additional DDC wire. DDC support automatically transfers monitor
data (e.g. type, name, max. horizontal frequency, timing
definitions) to the graphics card. The graphics card may also
send instruction to the monitor via the DDC line.
There are different DDC standards: DDC1, DDC2B, and DDC2AB.
Default Mode
Capabilities, resolutions and display mode the system operates with when you start your computer.
Delta frame
Frame containing only the data that has actually changed since the last frame. Delta frames are an efficient means of compressing image data. Compare key frame.
Digital
(1) Method of representing sound or other waves as a series of binary numbers. (2) Tuning method for radios in which the desired freq. is set by digital calculation. (3) Numeric display of information. Compare analog.
Digital Display
Also called TTL. A type of monitor that switches signals ON or OFF to determine display color. Types of digital displays include the IBM Enhanced Color Display or Monochrome Display.
Digitize
Process of turning an analog signal into digital data.
Digitizer
Input device in the CAD area, used for scanning printed graphics or drawings, i.e. converting them to digital computer graphics.
Direct3D
3D software interface (3D-API) from Microsoft for Windows 95 and Windows NT. Uses DirectDraw.
DirectColor
Generic term for TrueColor, RealColor and HiColor. Color information is passed directly to the D/A converter instead of being translated by a look-up table. Therefore full color information must be saved for each pixel.
DirectX
Interactive media technologies for Windows 95 and Windows NT. Allows the development of high-performance interactive applications by extending to the developers the full performance of the underlying hardware. Includes the DirectDraw, Direct3D, DirectSound, DirectInput, and DirectPlay APIs.
Dither
Process of representing a color by mixing dots of closely related colors.
DMA
Direct memory access, a method of data transfer where information is transferred directly between system components without the help of the CPU.
Double buffering
Also called page flipping. The display buffer has double size. The next image can be drawn in the part of the display buffer which is invisible at first. When it is ready, this part will be displayed, and in the other part the next image will be prepared. With this technique animations and games look more realistic than with a simple single buffer.
DPMS
Display Power Management Signaling; VESA standard which allows energy saving operation of monitors.
DRAM
Dynamic Random Access Memory, memory for read and write operations which is non-permanent.
Driver
Part of a software program that interacts with a particular piece of equipment in your computer system (i.e. video boards, printers, and keyboards). Drivers are often loaded by your config.sys at system boot.
Dual screen
DOS screen and high-resolution graphics screen appearing on two separate monitors.
Electrically erasable programmable read only memory; used like a ROM permanent memory chip, but can be programmed and erased to replace DIP switches and jumpers on new graphics boards.
EGA
IBM Enhanced Graphics Adapter, which allows 640 x 350 pixels with 16 colors.
Enhanced Color Display (ECD)
IBM Enhanced Color Display capable of 640 x 350 resolution.
Expansion Board
Device used to expand a computer's capability.
Expansion Slot
Electrical connection within the computer used for the addition of Expansion Boards.
Also called VGA output connector. 26-pin connector for connecting expansion boards to a graphics board using a flat cable.
Filter
Special effect applied to a video clip or image to alter its appearance. Filters can also correct problems involving color balance or brightness and contrast.
Fixed Frequency Monitor
Analog monitor which can only sync to a very narrow range of scan frequencies at certain resolutions and refresh rates.
Fog
Fading effect that depends on an object's distance from the viewer.
fps
Frames per second. Measurement unit for the frame rate.
Frame
Single video image.
Frame Rate
Number of images shown per time unit. Software videos have a fixed frame rate. When playing back the actual frame rate achieved can differ to the rate defined in the video considerably.
Frame size
Width and height of a frame expressed in pixels.
Frequency
Number of samples per second in a sound or video file. The higher the frequency, the better the quality of the sound or video.
3D processor from 3Dlabs.
Graphics accelerator
Device the purpose of which is to increase speed in performance-demanding graphical environments.
Grayscales
Grayscale image consists of different shades of gray (like a black-and-white photograph). This normally means that 254 different grayscales plus black and white (= 256) are used.
length of the horizontal synchronization pulse for a monitor, given in microseconds
Heidi
AutoDesk's Heidi Development Kit helps developing graphics intensive software, especially the drawing and display portion of the programming, such as render, pan, zoom, etc.
Hercules Graphics Card (HGC)
Video adapter that provides bit mapped single color graphics.
Hexadecimal Notation
A base-16 numbering system that uses numbers and letters. The hexadecimal sequence begins: 1 2 3 4 5 6 7 8 9 A B C D E F, then 10, 11 etc.
HiColor
designates 15 bits per pixel or 16 bpp graphics mode, i.e. 32,768 or 65,536.
Hoops
3D software interface (3D-API) from Ihaca Software.
Horizontal Frequency
Rate at which a monitor displays each scan line, usually measured in kilohertz (kHz). The value must be set depending on the operating limits of the monitor in order not to damage it.
Hue
Synonym for color.
Input/Output port. An address used to access a hardware device.
Indexed 16 and 256 Color Images
Indexed color images contain a color table in the file. This
table lists all the colors that could be used in the file. An
indexed 16-colour image contains a table with 16 color entries (4
bits) whereas an indexed 256 color image 256 colors are listed (8
bits).
Other colors can be simulated in a way similar to using
grayscales in a black-and-white image, by simply positioning the
pixels in varying densities. The eye then sees color mixtures
that are not actually in the color table.
You can transform images into indexed color images in order to
load them into programs such as Windows Paintbrush, or just to
see them on monitors that can only display 256 or 16 colors.
Interlaced Display
Monitor that refreshes every other scan line (odd or even) every other pass of the screen. Thus higher graphics resolution is possible, but more flickering occurs than with non-interlaced monitors which refresh the entire screen (every scan line) every pass of the screen.
Interrupt Request (IRQ)
Signal used by a device, such as a mouse, to inform the CPU that it is present and functioning and to trigger certain procedures.
Small plastic plug that fits over a pair of pins. When the plug straddles two pins it makes an electrical connection. The computer makes decisions based on whether the connection is made or not. A group of jumper pins is called a jumper block.
Kilobits per second, a quantity for measuring transmission speeds.
This is a hardware function of the graphics processor chip. Only the starting and ending coordinates of a line are supplied by the CPU. The rest of the work drawing the line is then done by the graphics processor.
Luminance
Portion of a video signal corresponding to brightness value - essentially the black-and-white foundation of a color video picture.
IBM Monochrome Display Adapter.
Monochrome Display
Monitor that displays information in one color only; sometimes called a black & white display.
Morphing
Special effect in which one shape is gradually transformed into another.
Multi-frequency Monitor
Type of monitor that supports a wide range of horizontal scanning frequencies and vertical refresh frequencies. This type of monitor accepts inputs from many different video display adapters.
3D software interface (3D API) for Windows NT and Windows 95, licensed from Microsoft and based on Iris GL from Silicon Graphics.
Selection of colors from which to choose. Your board provides as many as 16.7 million simultaneous colors from a palette of 16.7 million. This capability is sometimes referred to as TrueColor. It is believed that the human eye can discern no more than 16.7 million colors.
PCI bus
Peripheral Component Interconnect bus; system of parallel data lines to transfer information between individual system components, especially to expansion boards.
Peripheral Equipment
Auxiliary equipment connected to a computer (e.g. monitor, printer, keyboard, etc.).
Pixel
Short for picture element; the smallest field displayed on the monitor; could be compared to the dots which form images in photos printed in newspapers. Also called pel.
Pixel clock
Also called pixel frequency. Number of pixels drawn per second in MHz (million pixels per second). The values are either fixed or freely programmable.
Pixel depth
Also called color depth. Number of bits of color information per pixel. A system using eight bits per pixel can display 256 colors. A system using 16 bits per pixel can display 65,536 colors. A system using 24 bits per pixel can display over 16.7 million colors. Twenty-fourbit color is often called true color because the human eye can distinguish among approximately six million different colors, or fewer than are available in a 24-bit color system. 24 bits means 8 bit for each RGB. With 32 bit pixel depth 8 bits are used in addition for an Alpha Channel.
Polygon Fill
Special hardware (chip) routine used to fill polygons with pixel information.
Primary Display
Monitor which is active when you power on your system.
PS/2 Display Adapter
IBM VGA board for Industry Standard Architecture (AT bus) computers.
Random Access Memory; memory that can be read from and written to.
RealColor
normally designates a 15 bits per pixel or 16 bpp graphics mode, i.e. 32,768 or 65,536 colors.
Refresh rate
Vertical refresh rate in Hz indicates how many full images per second are displayed on the monitor. The higher the refresh rate, the less the display will flicker.
Rendering
Process of displaying an object with shading effects to yield a more natural three-dimensional appearance.
Resolution
Number of pixels displayed in horizontal and vertical direction on the monitor. The higher the resolution, the crisper and sharper the images appear.
RGB 8Color
RGB8 color file types are 3 bit types in which each pixel can have one of 8 colors. The RGB8 color images are automatically transformed into indexed 16 color images whereby the 8 colors are retained but space for further 8 colors is created. It is not possible to transform an existing file into an RGB8 color file type.
RGB Color Model
Monitors use additive mixing of the three basic colors red, green and blue to create images on the screen with an infinite number of colors. Image data is therefore processed via data for RGB color combinations. The combinations of the three basic colors create a color model whose origin is the color black and the opposite value is the color white.
RGB True Color
RGB stands for red - green - blue. All the colors that are used in this file are created additively mixing parts of the three basic colors. The parts of the three basic colors can be varied in 256 steps. If you mix all these colors together a total of 16.7 million possible color combinations is attainable (3x8 bits = 24 bits, 2 to the power of 24 = 16.7 million). As the human eye can not tell the differences between color hues from about this level, such an image is termed 'True Color', i.e. 'as in real life'.
ROM
Read Only Memory; memory space in your computer for storing permanent operating instructions. It cannot be written to.
Amount of gray in a color determining the intensity and purity of a color. A color with a high saturation value is optically very intensive. A color with a low saturation value appears weak (i.e. with less color content).
Scaling
Transformation of image data to different sizes.
Shading (flat, Gouraud, Phong)
Shading or rendering is a way to define the colors on curved
surfaces in order to give an object a natural appearance. To
achieve this, the surfaces are subdivided into many small
triangles. The three most important 3-D shading methods differ in
the algorithm used to apply to these triangles:
- Flat shading: In this simplest method each triangle gets one
single color, resulting in a faceted appearance of the surface.
- Gouraud shading: The color shades on a triangle are calculated
by interpolating the vertex colors, resulting in a smooth
appearance of the surface.
- Phong shading: The color shades on a triangle are calculated by
interpolating the vertex colors, additionally regarding the
normal vector at each triangle (i.e. its orientation in space).
Single screen
DOS screen and high-resolution graphics screen appear on the same monitor.
Stencil
Special information for each pixel, whether and how it is drawn and redrawn.
Sync
Stable condition which exists when two repetitive events maintain a constant time relationship; your monitor is in sync with the signals from your board when the display is correct and stable.
Wrapping a bitmap around an object, including perspective correction, for example a wallpaper on a wall or a wood texture on furniture. A video can also be used as texture map.
TrueColor
Ability to display 16.7 million simultaneous colors (24 or 32 bits per pixel). Color information saved in display memory is not translated by look-up table, but passed directly to the D/A converter. Thus full color information must be saved for each pixel. It is believed that the human eye can discern no more than 16.7 million colors. See 'palette'.
Length of the vertical synchronization pulse for a monitor, given in microseconds.
Variable Frequency Display (VFD)
Monitor that is capable of displaying a wide range of resolutions through it's ability to sync to a wide range of horizontal and vertical scan frequencies.
Vertical Frequency
Rate at which the monitor screen is refreshed. Usually measured in hertz (Hz).
VESA
Video Electronics Standard Association; consortium for the standardization of computer graphics.
VGA
IBM Video Graphics Adapter with a standard resolution of 640 x 480 with 16 colors.
VRAM
Video Random Access Memory; memory chip for fast graphics boards.
The image information of individual frames is comprised of a brightness part and 2 color parts. The color part is calculated by evaluating the difference to the brightness value. This method was first utilized in television technology.
3-D depth information (position in the third dimension) for each pixel.
Zooming
Increased display of an image section.