Computer graphics

The first computers of the 40s of the 20th century ("ABC", 1942, "ENIAC", 1946, "EDSAC", 1949, "MESM", 1950) were developed and used strictly for calculations and did not have separate funds for working with graphics. However, even then, some enthusiasts tried to use first-generation computers on electron tubes to obtain and process images. By programming the memory of computers and information output devices built on the basis of a matrix of electric lamps, it was possible to obtain simple patterns. Incandescent lamps turned on and off in a certain order, forming images of various figures.

In the late 40s and early 50s, many computers began to use cathode ray tubes (CRTs) in the form of oscilloscopes, or Williams tubes , which were used as RAM. Theoretically, writing 0 or 1 in a certain order to such a memory, a certain image could be displayed on the screen, but in practice this was not used. In 1952, British engineer Alexander Douglas ( Alexander Shafto "Sandy" Douglas ) wrote the comic program " OXO " (Tic-Tac-Toe) for the EDSAC programmable computer (1949), which became the first computer game in history. The image of the lattice and zeros with crosses was constructed by programming a Williams tube or traced on a neighboring CRT.

In the 50s, the computing capabilities of computers and the graphic capabilities of peripheral devices did not allow for high detail, but made it possible to perform character-by-character output of images to screens of monitors and standard printers. Images were built from alphanumeric characters ( symbolic graphics , later came the name ASCII-graphics and ASCII-Art ). The principle is simple: the difference in the density of alphanumeric characters and the inability of human vision to distinguish details from a distance made it possible to create drawings and pseudographic objects on a computer. Similar images on paper were created by typists in the late 19th century.

In 1950, enthusiast Ben Laposky , a mathematician, artist, and draftsman, began experimenting with the oscilloscope screen, creating complex, dynamic shapes - oscillations . The dance of light was created by the most complicated settings on this cathode-ray device. For capturing images, high-speed photography and special lenses were used, later pigmented filters were added to fill the pictures with color.

In 1950, the Whirlwind-I military computer (in Russian "Whirlwind", "Hurricane"), built into the US SAGE air defense system, first used a monitor as a means of displaying visual and graphic information.

In 1955, the Light Pen was invented in the laboratory of the Massachusetts Institute of Technology (MIT ) . This is a photosensitive computer input device, mainly a nautilus, which is used to select text, draw images, and interact with user interface elements on a computer screen or monitor. The pen only works well with CRT monitors, because they scan the screen pixel by pixel, which gives the computer a way to track the expected scan time with the electron beam and determine the position of the pen based on the last scan time stamp. At the tip of the pen is a photocell emitting electronic pulses and at the same time reacting to a peak glow corresponding to the moment of passage of the electron beam. It is enough to synchronize and correlate the pulse with the position of the electron gun to determine where exactly the pen points.

Light pens were widely used in computing terminals of the 1960s. With the advent of LCD (LCD) monitors in the 90s, they almost went out of use, since the work of the light pen became impossible with the screens of these devices.

In 1957, engineer Russell A. Kirsch of the US National Bureau of Standards invented the first scanner for the SEAC computer and received the first digital image on it - a scan photo of his son Walden.

In the 60s of the XX century , the real flowering of computer graphics began . With the advent of new high-performance computers by the standards, monitors with transistors (2nd generation of computers) and later chips (3rd generation of computers), computer graphics became not only a field of enthusiasts, but a serious scientific and practical direction in the development of computer technology. The first supercomputers appeared ( SVS 6600 and Cray-1 ), which made it possible to work not only with fast calculations, but also with computer graphics at a new level.

In 1960, design engineer William Fetter of the Boeing Aircraft Corporation first coined the term "computer graphics . " Drawing the design of the cockpit of the aircraft on a working computer, he decided in this way to describe the nature of his activity in the technical documentation. In 1964, Ulyam Fetter also created on the computer a wire graphic model of a person called "Boeing man", he is also the "first man" used later in television advertising.

In 1962, programmer Steve Russell of MIT on the DEC PDP-1 computer developed a separate program with graphics - the computer game “ Spacewar! ". Its creation took about 200 man-hours . The game used a joystick and had interesting physics with nice graphics. However, the first computer game, but without graphics, can be considered the program of Alexander Douglas "OXO" ("Tic Tac Toe", 1952)

In 1963, based on the TX-2 computer, an American MIT software engineer, computer graphics pioneer Ivan Edward Sutherland created the software and hardware complex, which made it possible to draw points, lines, and circles on a tube with a light pen . Basic actions with primitives were supported: moving, copying, etc. In fact, this was the first vector editor that became the prototype of modern CAD (computer-aided design systems) such as AutoCAD or Compass-3D. Also, this program can be considered the first graphical interface that came out 10 years before Xerox Alto (1973), before the term itself appeared. In 1968, Ivan Sutherland created the prototype of the first computer helmet of virtual reality, called the "Damocles Sword" by analogy with the ancient Greek legend.

In the mid-1960s Developments appeared in industrial applications of computer graphics. Thus, under the leadership of T. Mofett and N. Taylor , Itek developed a digital electronic drawing machine ( plotter ).

In 1963, Bell Labs programmer Edward E. Zajac developed the first computer animation - the movement of a satellite around the Earth . The animation was demonstrated by a theoretical satellite that used gyroscopes to support its orientation relative to the Earth. All computer processing was done on computers of the IBM 7090 or 7094 series using the ORBIT program.

In subsequent years, other more complex and meaningful animations come out: “Tesseract” (“Tesseract”, aka “Hypercube”, 1965) by Michael Knoll from “Bell Labs”, “Hummengbird” (“Hummingbird”, 1967.) Charles Tsuri and James Schafers, “Kitty” (1968) by Nikolai Konstantinov, “Metadata” (“Metadata”, 1971) by Peter Falders, etc.

The IBM 2250 , the first commercial graphics terminal for the IBM / 360 mainframe , was launched in 1964 .

In 1964, General Motors, together with IBM, introduced the DAC-1 computer-aided design system.

In 1967, Professor Douglas Engelbart designed the first computer mouse (XY coordinate pointer) and showed its capabilities at an exhibition in San Francisco in 1968.

In 1967, IBM employee Arthur Appel describes an algorithm for removing invisible edges (including partially hidden), later called ray casting , the starting point of modern 3D graphics and photorealism.

In 1968 ^[1] in the USSR, a group led by N. N. Konstantinov created a computer model for simulating cat movements . The BESM-4 machine, executing the written program for solving differential equations, painted the cartoon “ Kitty ” ^[2] - a breakthrough for its time. Similar motion dynamics algorithms were rediscovered in the west only in the 80s! For visualization, an alphanumeric printer was used .

In the same year computer graphics are making significant progress with the advent of the ability to memorize images and display them on a computer display — a cathode ray tube . The first raster monitors appear.

In the 70s , the first color monitors and color graphics appeared - a new leap in the development of computer graphics. Supercomputers with color displays began to be used to create special effects in films (the 1977 science fiction epic Star Wars directed by George Lucas, the fantastic horror movie Alien) of the 20th century Fox studio and director Ridley Scott , later underestimated scientifically -fantastic 1982 film "Tron" (Eng. Tron) by Walt Disney and directed by Stephen Lisberger ). During this period, computers became even faster, they were taught how to draw 3D images, three-dimensional graphics appeared and a new direction of visualization - fractal graphics. There were personal computers with graphical interfaces that use a computer mouse (Xerox Alto, 1973).

In 1971, mathematician Henri Gouraud, in 1972 Jim Blinn, and in 1973, Bui Tuong Fong developed shading models that allow the graphic to go beyond the plane and accurately display the depth of the scene. Jim Blinn became an innovator in the implementation of relief maps, techniques for modeling uneven surfaces, and Fong's algorithm subsequently became the main one in modern computer games.

In 1972, computer graphics pioneer Edwin Catmull created the first 3D image - a wire and textured model of his own left hand.

In 1975, the French mathematician Benoît B. Mandelbrot , programming an IBM model computer, builds on it an image of the calculation results of a complex mathematical formula (Mandelbrot set), and as a result of the analysis of the obtained repeating patterns gives the beautiful images the name " fractal " (with lat fractional, broken). Fractal geometry arises and a new promising direction in computer graphics is fractal graphics .

At the end of the 70s , with the advent of 4th generation personal computers - on microprocessors, graphics from industrial systems transferred to workplaces and to homes of ordinary users. The industry of video games and computer games is emerging. The first mass personal computer with color graphics was the Apple II PC (1977), later the Apple Macintosh (1984).

In the 80s , with the development of the video system for personal computers IBM PC (1981 ), the graphics became more detailed and color rendering (image resolution was increased and the color palette expanded). The first video standards MDA, CGA, EGA, VGA, SVGA. The first standards for file graphic formats were developed, for example GIF (1987), and graphic modeling emerges.

Key Applications

Scientific graphics - the first computers were used only to solve scientific and production problems. In order to better understand the results obtained, they were graphically processed, graphs, charts, and drawings of the calculated structures were built. The first graphics on the machine were obtained in symbol print mode. Then special devices appeared - plotters (plotters) for drawing drawings and graphs with an ink pen on paper. Modern scientific computer graphics make it possible to conduct computational experiments with a visual representation of their results.

Business Graphics is a field of computer graphics designed to provide a visual representation of various performance indicators of institutions. Planned indicators, reporting documentation, statistical summaries - these are the objects for which illustrative materials are created using business graphics. Business graphics software is included in the spreadsheet.

Design graphics are used in the work of design engineers, architects, inventors. This is an essential element of CAD (design automation systems). Using design graphics, you can get both flat images (projections, sections), and spatial three-dimensional images.

Illustrative graphics are arbitrary drawing and plotting on a monitor screen. Illustrative graphics packages are for general purpose application software. The simplest software tools for illustrative graphics are called graphic editors.

Art and advertising graphics have become popular thanks in large part to television. Using a computer, commercials, cartoons, computer games, video tutorials, video presentations are created. Graphics packages for these purposes require large computer resources for speed and memory. A distinctive feature of these graphics packages is the ability to create realistic images and moving pictures. Obtaining drawings of three-dimensional objects, their rotation, approximation, removal, deformation is associated with a large amount of computation. The transmission of the illumination of an object depending on the position of the light source, on the location of the shadows, on the surface texture, requires calculations that take into account the laws of optics.

Pixel art - pixel art, an important form of digital art, is created using raster graphics software, where images are edited at the pixel level. In the enlarged part of the image, individual pixels are displayed as squares and are easy to see. In digital images, a pixel (or image element) is a single point in a bitmap image. Pixels are placed on a regular two-dimensional grid and are often represented by dots or squares. The graphics in most older (or relatively limited) computer and video games, graphing calculator games, and many mobile phone games are mostly pixel graphics.

Computer animation is the acquisition of moving images on a display screen. The artist creates on-screen drawings of the initial and final position of moving objects; all intermediate states are calculated and displayed by the computer, performing calculations based on the mathematical description of this type of movement. This animation is called key frame animation . There are also other types of computer animation: procedural animation , shape animation , programmed animation and animation, where the artist himself draws all the frames manually. The resulting drawings, sequentially displayed on the screen with a certain frequency, create the illusion of movement.

Multimedia is a combination of high-quality images on a computer screen with sound. The most widely used multimedia systems are in the fields of training, advertising, and entertainment.

Scientific work

Computer graphics is also one of the areas of scientific activity. In the field of computer graphics, dissertations are defended, and various conferences are held:

• Siggraph conference held in the USA
• Eurographics conferences are held annually by Eurographics in Europe
• Schedule conference held in Russia
• CG event held in Russia
• CG Wave 2008 , CG Wave, held in Russia

By the methods of specifying images, graphics can be divided into categories:

2D Graphics

Двухмерная (2D — от англ. two dimensions — «два измерения») компьютерная графика классифицируется по типу представления графической информации, и следующими из него алгоритмами обработки изображений. Обычно компьютерную графику разделяют на векторную и растровую, хотя обособляют ещё и фрактальный тип представления изображений.

Векторная графика

Векторная графика представляет изображение как набор геометрических примитивов. Обычно в качестве них выбираются точки, прямые, окружности, прямоугольники, а также как общий случай, кривые некоторого порядка. Объектам присваиваются некоторые атрибуты, например, толщина линий, цвет заполнения. Рисунок хранится как набор координат, векторов и других чисел, характеризующих набор примитивов. При воспроизведении перекрывающихся объектов имеет значение их порядок.

Изображение в векторном формате даёт простор для редактирования. Изображение может без потерь масштабироваться, поворачиваться, деформироваться, также имитация трёхмерности в векторной графике проще, чем в растровой. Дело в том, что каждое такое преобразование фактически выполняется так: старое изображение (или фрагмент) стирается, и вместо него строится новое. Математическое описание векторного рисунка остаётся прежним, изменяются только значения некоторых переменных, например, коэффициентов.

При преобразовании растровой картинки исходными данными является только описание набора пикселей, поэтому возникает проблема замены меньшего числа пикселей на большее (при увеличении), или большего на меньшее (при уменьшении). Простейшим способом является замена одного пикселя несколькими того же цвета (метод копирования ближайшего пикселя: Nearest Neighbour). Более совершенные методы используют алгоритмы интерполяции, при которых новые пиксели получают некоторый цвет, код которого вычисляется на основе кодов цветов соседних пикселей. Подобным образом выполняется масштабирование в программе Adobe Photoshop ( билинейная и бикубическая интерполяция ).

Вместе с тем, не всякое изображение можно представить как набор из примитивов. Такой способ представления хорош для схем, используется для масштабируемых шрифтов, деловой графики, очень широко используется для создания мультфильмов и просто роликов разного содержания.

Растровая графика

Растровая графика всегда оперирует двумерным массивом (матрицей) пикселей. Каждому пикселю сопоставляется значение яркости, цвета, прозрачности — или комбинация этих значений. Растровый образ имеет некоторое число строк и столбцов.

Без особых потерь растровые изображения можно только лишь уменьшать, хотя некоторые детали изображения тогда исчезнут навсегда, что иначе в векторном представлении. Увеличение же растровых изображений оборачивается видом на увеличенные квадраты того или иного цвета, которые раньше были пикселями.

В растровом виде представимо любое изображение, однако этот способ хранения имеет свои недостатки: больший объём памяти, необходимый для работы с изображениями, потери при редактировании.

Raster graphics are used by designers, animators, artists working with individual graphic works and orders for individual sales. Raster images do not go into circulation and are not used in mass sales, because as the size increases, the image loses quality, but it is raster graphics that allow you to do almost picturesque work, more elaborate designs and faster designs, which are then edited and reproduced if necessary the desired format using vector programs.

Fractal Graphics

A fractal is an object whose individual elements inherit the properties of parent structures. Since a more detailed description of elements of a smaller scale occurs according to a simple algorithm, it is possible to describe such an object with just a few mathematical equations.

Fractals allow you to describe entire classes of images, the detailed description of which requires relatively little memory. Fractals, on the other hand, are poorly applicable to images outside these classes.

3D Graphics

Three-dimensional graphics (3D - from the English. Three dimensions - "three dimensions") operates with objects in three-dimensional space. Usually the results are a flat picture, a projection . Three-dimensional computer graphics are widely used in cinema, computer games.

Three-dimensional graphics are polygonal and voxel . Voxel graphics are similar to raster graphics. An object consists of a set of three-dimensional figures, most often cubes. And in polygonal computer graphics, all objects are usually represented as a set of surfaces, the minimum surface is called a polygon . Triangles are usually chosen as the polygon.

3D graphics 3D graphics compared to 2D graphics are graphics that use a three-dimensional representation of geometric data. For performance reasons, this is stored on the computer. This includes images that may be for later display or for viewing in real time.

All visual transformations in vector (polygonal) 3D graphics are controlled by matrices (see also: affine transformation in linear algebra ). In computer graphics, three types of matrices are used:

• rotation matrix
• shift matrix
• scaling matrix

Any polygon can be represented as a set of coordinates of its vertices . So, the triangle will have 3 vertices. The coordinates of each vertex are a vector (x, y, z). Multiplying the vector by the corresponding matrix, we get a new vector. Having made such a transformation with all the vertices of the polygon, we get a new polygon, and having converted all the polygons, we get a new object rotated / shifted / scaled relative to the original one.

Three-dimensional graphics competitions are held annually, such as Magick next-gen or Dominance War .

CGI Graphics

CGI ( English computer-generated imagery , letters. " Computer-generated images") - images obtained by the computer on the basis of calculation and used in the visual arts , printing , cinematic special effects , on television and in simulators . Moving images are handled by computer animation , which is a narrower area of ​​CGI graphics.

Presentation of colors on a computer

For the transmission and storage of color in computer graphics, various forms of its representation are used. In general, a color is a set of numbers, coordinates in a certain color system.

Standard methods for storing and processing color in a computer are determined by the properties of human vision. The most common RGB systems for displays and CMYK for work in printing.

Sometimes a system with more than three components is used. The spectrum of reflection or emission of the source is encoded, which allows a more accurate description of the physical properties of color. Such schemes are used in photorealistic three-dimensional rendering.

The Real Side of Graphics

Any image on the monitor, due to its plane, becomes raster, since the monitor is a matrix, it consists of columns and rows. Three-dimensional graphics exist only in our imagination, since what we see on the monitor is a projection of a three-dimensional figure, and we are already creating the space ourselves. Thus, the visualization of graphics is only raster and vector, and the method of visualization is only a raster (a set of pixels), and the way the image is set depends on the number of these pixels.

In the era of the very first graphic displays (monitors), there were CRT displays without a raster, with electron beam control like an oscilloscope . The figures displayed by such displays were purely vectorial. With the development of software and the complexity of the tasks to be solved, graphic displays of this type were found to be unpromising, since they did not allow the formation of sufficiently complex images. A similar principle of image formation is used in vector plotters . The difference is that on a vector display, the complexity of the picture is limited by the afterglow of the phosphor , and there is no such restriction on the vector plotter .

• Pseudographics
• Digital video
• Multimedia
• Segmentation (image processing)
• Graphical user interface

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