ASCII, abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of technical limitations of computer systems at the time it was invented, ASCII has just 128 code points, of which only 95 are printable characters, which severely limited its scope. Modern computer systems have evolved to use Unicode, which has millions of code points, but the first 128 of these are the same as the ASCII set.
In computer graphics and digital photography, a raster graphic represents a two-dimensional picture as a rectangular matrix or grid of square pixels, viewable via a computer display, paper, or other display medium. A raster is technically characterized by the width and height of the image in pixels and by the number of bits per pixel. Raster images are stored in image files with varying dissemination, production, generation, and acquisition formats.
In computer science, an escape sequence is a combination of characters that has a meaning other than the literal characters contained therein; it is marked by one or more preceding characters.
ANSI escape sequences are a standard for in-band signaling to control cursor location, color, font styling, and other options on video text terminals and terminal emulators. Certain sequences of bytes, most starting with an ASCII escape character and a bracket character, are embedded into text. The terminal interprets these sequences as commands, rather than text to display verbatim.
The BMP file format or bitmap, is a raster graphics image file format used to store bitmap digital images, independently of the display device, especially on Microsoft Windows and OS/2 operating systems.
The VT220 is a computer terminal introduced by Digital Equipment Corporation (DEC) in November 1983. The VT240 added monochrome ReGIS vector graphics support to the base model, while the VT241 did the same in color. The 200 series replaced the successful VT100 series, providing more functionality in a much smaller unit with a much smaller and lighter keyboard. Like the VT100, the VT200 series implemented a large subset of ANSI X.364. Among its major upgrades was a number of international character sets, as well as the ability to define new character sets.
The Color Graphics Adapter (CGA), originally also called the Color/Graphics Adapter or IBM Color/Graphics Monitor Adapter, introduced in 1981, was IBM's first color graphics card for the IBM PC and established a de facto computer display standard.
The Monochrome Display Adapter is IBM's standard video display card and computer display standard for the IBM PC introduced in 1981. The MDA does not have any pixel-addressable graphics modes, only a single monochrome text mode which can display 80 columns by 25 lines of high-resolution text characters or symbols useful for drawing forms.
Text mode is a computer display mode in which content is internally represented on a computer screen in terms of characters rather than individual pixels. Typically, the screen consists of a uniform rectangular grid of character cells, each of which contains one of the characters of a character set; at the same time, contrasted to graphics mode or other kinds of computer graphics modes.
The 8563 Video Display Controller (VDC) was an integrated circuit produced by MOS Technology. It was used in the Commodore 128 (C128) computer to generate an 80-column RGB video display, running alongside a VIC-II which supported Commodore 64-compatible graphics. The DCR models of the C128 used the later and more technically advanced 8568 [D]VDC controller.
The TMS9918 is a video display controller (VDC) manufactured by Texas Instruments, in manuals referenced as "Video Display Processor" (VDP) and introduced in 1979. The TMS9918 and its variants were used in the ColecoVision, CreatiVision, Memotech MTX, MSX, NABU Personal Computer, SG-1000/SC-3000, Spectravideo SV-318, SV-328, Sord M5, Tatung Einstein, TI-99/4, Casio PV-2000, Coleco Adam, Hanimex Pencil II, and Tomy Tutor.
The Tektronix 4010 series was a family of text-and-graphics computer terminals based on storage-tube technology created by Tektronix. Several members of the family were introduced during the 1970s, the best known being the 11-inch 4010 and 19-inch 4014, along with the less popular 25-inch 4016. They were widely used in the computer-aided design market in the 1970s and early 1980s.
Hold-And-Modify, usually abbreviated as HAM, is a display mode of the Commodore Amiga computer. It uses a highly unusual technique to express the color of pixels, allowing many more colors to appear on screen than would otherwise be possible. HAM mode was commonly used to display digitized photographs or video frames, bitmap art and occasionally animation. At the time of the Amiga's launch in 1985, this near-photorealistic display was unprecedented for a home computer and it was widely used to demonstrate the Amiga's graphical capability. However, HAM has significant technical limitations which prevent it from being used as a general purpose display mode.
Netpbm is an open-source package of graphics programs and a programming library. It is used mainly in the Unix world, where one can find it included in all major open-source operating system distributions, but also works on Microsoft Windows, macOS, and other operating systems.
The Glyph Bitmap Distribution Format (BDF) by Adobe is a file format for storing bitmap fonts. The content takes the form of a text file intended to be human- and computer-readable. BDF is typically used in Unix X Window environments. It has largely been replaced by the PCF font format which is somewhat more efficient, and by scalable fonts such as OpenType and TrueType fonts.
The VT420 is an ANSI standard computer terminal introduced in 1990 by Digital Equipment Corporation (DEC). The 420 is the only model in the 400 series, replacing the VT320. There are no color or graphics-capable 400 series terminals; the VT340 remained in production for those requiring ReGIS and Sixel graphics and color support. The entire lineup of VT300s and VT420 was eventually replaced by the relatively unknown VT500 series starting in 1993.
In computing, indexed color is a technique to manage digital images' colors in a limited fashion, in order to save computer memory and file storage, while speeding up display refresh and file transfers. It is a form of vector quantization compression.
ReGIS, short for Remote Graphic Instruction Set, is a vector graphics markup language developed by Digital Equipment Corporation (DEC) for later models of their famous VT series of computer terminals. ReGIS supports rudimentary vector graphics consisting of lines, circular arcs, and similar shapes. Terminals supporting ReGIS generally allow graphics and text to be mixed on-screen, which makes construction of graphs and charts relatively easy.
The VT320 is an ANSI standard computer terminal introduced by Digital Equipment Corporation (DEC) in 1987. The VT320 is the text-only version, while the VT330 adds monochrome ReGIS, Sixel and Tektronix 4010 graphics, and the VT340 adds color.
Waveform graphics is a simple vector graphics system introduced by Digital Equipment Corporation (DEC) on the VT55 and VT105 terminals in the mid-1970s. It was used to produce graphics output from mainframes and minicomputers. DEC used the term "waveform graphics" to refer specifically to the hardware, but it was used more generally to describe the whole system.
