Three-dimensional image and raster surfaces. Types of computer graphics. Computer graphics is a branch of computer science that studies the means and methods of creating and processing graphic images using computer technology. Using multiprocessing

As mentioned above, computer graphics can be divided into three main categories based on how images are described: raster, vector and three-dimensional graphics. Among two-dimensional graphics, pixel and fractal graphics stand out in a special way. 3D, CGI and infographics also require special consideration.

Pixel graphics

The term "pixel graphics" (from the English. pixel ) refers to a form of digital image created on a computer using a raster graphics editor, where the image is edited at the pixel (dot) level and the image resolution is so low that individual pixels are clearly visible.

There is a common misconception that any drawing made using raster editors is pixel art. This is not true, pixel image differs from the usual raster technology - manual editing of the image pixel by pixel. Therefore, pixel art is characterized by its small size, limited color palette and (usually) lack of anti-aliasing.

Pixel graphics use only the simplest tools of raster graphics editors, such as Pencil, Straight (line) or Fill (fill with color). Pixel graphics are reminiscent of mosaics and cross-stitch or beadwork - since the design is made up of small colored elements, similar to the pixels of modern monitors.

Fractal graphics

A fractal is an object formed from irregular individual parts that are similar to the whole object. Since a more detailed description of smaller-scale elements occurs using a simple algorithm, such an object can be described with just a few mathematical equations.

Rice. 8.5.

Fractal graphics are indispensable when creating artificial mountains, clouds, and sea waves. Thanks to fractals, complex objects are easily depicted, the images of which are similar to natural ones. Fractals make it possible to describe entire classes of images, the detailed description of which requires relatively little memory (Fig. 8.5). On the other hand, fractals are poorly applicable to images outside of these classes.

3D graphics

Three-dimensional graphics (3D - from English 3 Dimensions – three dimensions) – three dimensions of an image) – a section of computer graphics, a set of techniques and tools (both software and hardware) designed to depict three-dimensional objects (Fig. 8.6).

Rice. 8.6.

3D image on a plane differs from a two-dimensional one in that it includes the construction of a geometric projection of a three-dimensional model of the scene onto a plane (for example, a computer screen) using specialized programs (however, with the creation and implementation 3D -displays and 3D -printers, three-dimensional graphics do not necessarily include projection onto a plane). In this case, the model can either correspond to objects from the real world (cars, buildings, hurricane, asteroid) or be completely abstract (projection of a four-dimensional fractal).

3D modeling is the process of creating a three-dimensional model of an object. Task 3D - modeling – to develop a three-dimensional image of the desired object. With the help of three-dimensional graphics, you can create an exact copy of a specific object, and develop a new, even unreal representation of an object that never existed.

Three-dimensional graphics operate with objects in three-dimensional space. Usually the results are a flat picture, a projection. Three-dimensional computer graphics are widely used in television, cinema, computer games and the design of printing products.

Three-dimensional graphics are actively used to create images on the plane of a screen or printed sheet in science and industry (for example, in design automation systems (CAD)); for creating solid elements: buildings, machine parts, mechanisms), architectural visualization (this includes the so-called “virtual archeology”), in modern medical visualization systems.

3D graphics typically deal with virtual, imaginary, three-dimensional space that is displayed on the flat, two-dimensional surface of a display or piece of paper. Any image on the monitor, due to the plane of the latter, becomes raster, since the monitor is a matrix, it consists of columns and rows. Three-dimensional graphics exist only in our imagination - what we see on the monitor is a projection of a three-dimensional figure, and we ourselves create the space. Thus, graphics visualization can only be raster and vector, and the visualization method is only a raster (a set of pixels); the method of defining the image depends on the number of these pixels.

Currently, several methods are known for displaying three-dimensional information in volumetric form, although most of them represent volumetric characteristics very conditionally, since they work with a stereo image. From this area we can note stereo glasses, virtual helmets, 3D -displays capable of showing three-dimensional images.

-graphic arts

The term "CGI graphics" computer generated imagery stands for computer-generated images) refers to still and moving images generated by three-dimensional computer graphics and used in the visual arts, printing, cinematic special effects, television, and simulation. Computer games typically use real-time computer graphics, but CGI-based in-game videos are also occasionally added.

The creation of moving images is done by computer animation, which is a narrower area of CGI graphics, also applicable in cinema, where it allows you to create effects that cannot be achieved using traditional makeup and animatronics. Computer animation can replace the work of stuntmen and extras, as well as scenery.

Infographics

The term "infographics" (from Lat. information awareness, explanation, presentation; and other Greek graphike - written, from grapho – I write) denote a graphical way of presenting information, data and knowledge.

The range of applications of infographics is huge - geography, journalism, education, statistics, technical texts. It helps not only to organize large amounts of information, but also to more clearly show the relationship of objects and facts in time and space, as well as demonstrate trends.

Infographics can be called any combination of text and graphics created with the intention of telling a story or conveying a fact. Infographics work where you need to show the structure and algorithm of something, the relationship of objects and facts in time and space, demonstrate a trend, show what something looks like, organize large amounts of information.

Infographics are a visual representation of information. Used where complex information needs to be presented quickly and clearly.

Animatronics – a technique used in cinematography, animation, and computer modeling to create special effects for moving artificial parts of the human body, animal body, or other objects.

Presentation of data on a computer monitor in graphical form was first implemented in the mid-50s for large computers used in scientific and military research. Since then, the graphical method of displaying data has become an integral part of the vast majority of computer systems, especially personal ones. Today, the graphical user interface is the de facto standard for software of various classes, starting with operating systems.

There is a special field of computer science that studies methods and means of creating and processing images using software and hardware computing systems - computer graphics. It covers all types and forms of representation of images that are accessible to human perception either on a monitor screen or as a copy on an external medium (paper, film, fabric, etc.). Without computer graphics it is impossible to imagine not only a computer, but also an ordinary, completely material world. Data visualization finds application in a variety of areas of human activity. For example, let's name medicine (computed tomography), scientific research (visualization of the structure of matter, vector fields and other data), modeling of fabrics and clothing, and development projects.

Depending on the method of image formation, computer graphics are usually divided into raster, vector and fractal.

Figure 1 Figure 2 Figure 3

A separate item is considered three-dimensional (3D) graphics, studying techniques and methods for constructing three-dimensional models of objects in virtual space. As a rule, it combines vector and raster methods of image generation.

Features of the color gamut are characterized by such concepts as black and white and color graphics. The titles of some sections indicate specialization in individual areas: engineering graphics, scientific graphics, Web graphics, computer printing and others.

At the intersection of computer, television and film technologies, a relatively new field has emerged and is rapidly developing. computer graphics and animation.

Entertainment plays a prominent role in computer graphics. There was even such a concept as a mechanism for graphical presentation of data ( Graphics Engine). The gaming software market has a turnover of tens of billions of dollars and often initiates the next stage of improvement in graphics and animation.

Although computer graphics serves only as a tool, its structure and methods are based on the advanced achievements of fundamental and applied sciences: mathematics, physics, chemistry, biology, statistics, programming and many others. This remark is true for both software and hardware for creating and processing images on a computer. Therefore, computer graphics is one of the most rapidly developing branches of computer science and in many cases acts as a “locomotive” pulling the entire computer industry along with it.

Fractal graphics

Fractal graphics are based on mathematical calculations. The basic element of fractal graphics is the mathematical formula itself, that is, no objects are stored in the computer’s memory and the image is constructed exclusively using equations. In this way, both the simplest regular structures and complex illustrations that imitate natural landscapes and three-dimensional objects are built.

3D graphics

Three-dimensional graphics have found wide application in such areas as scientific calculations, engineering design, and computer modeling of physical objects (Fig. 3). As an example, let's consider the most complex version of three-dimensional modeling - creating a moving image of a real physical body.

In a simplified form, spatial modeling of an object requires:

· design and create a virtual frame (“skeleton”) of an object that most closely matches its real form;

· design and create virtual materials that are similar in physical visualization properties to real ones;

· assign materials to different parts of the surface of an object (in professional jargon - “project textures onto an object”);

· configure the physical parameters of the space in which the object will operate - set lighting, gravity, atmospheric properties, properties of interacting objects and surfaces;

· set the trajectories of movement of objects;

· apply surface effects to the final animation video.

To create a realistic model of an object, geometric primitives (rectangle, cube, ball, cone, etc.) and smooth, so-called spline surfaces. In the latter case, the method most often used is bicubic rational B-splines on a non-uniform mesh (NURBS). The appearance of the surface is determined by a grid of reference points located in space. Each point is assigned a coefficient, the value of which determines the degree of its influence on the part of the surface passing near the point. The shape and “smoothness” of the surface as a whole depends on the relative position of the points and the magnitude of the coefficients.

After forming the “skeleton” of the object, it is necessary to cover its surface with materials. The whole variety of properties in computer modeling comes down to visualizing the surface, that is, calculating the coefficient of transparency of the surface and the angle of refraction of light rays at the boundary of the material and the surrounding space.

Surface painting is carried out using Gouraud methods (Gouraud) or Phong (Phong). In the first case, the color of the primitive is calculated only at its vertices, and then linearly interpolated along the surface. In the second case, a normal to the object as a whole is constructed, its vector is interpolated along the surface of the component primitives, and lighting is calculated for each point.

The light leaving a surface at a particular point toward the observer is the sum of its components multiplied by a factor associated with the material and color of the surface at that point. These components include:

· light coming from the back side of the surface, that is, refracted light (Refracted);

· light uniformly scattered by the surface (Diffuse);

specularly reflected light (Reflected);

glare, that is, reflected light from sources (Specular);

· own surface glow (Self Illumination).

The next stage is the application (“projecting”) of textures to certain areas of the object’s frame. In this case, it is necessary to take into account their mutual influence at the boundaries of primitives. Designing materials for an object is a difficult task to formalize; it is akin to the artistic process and requires at least minimal creative abilities from the performer.

After completing the design and visualization of the object, they begin to “revive” it, that is, set the movement parameters. Computer animation is based on key frames. In the first frame, the object is set to its original position. After a certain period (for example, in the eighth frame), a new position of the object is set, and so on until the final position. Intermediate values are calculated by the program using a special algorithm. In this case, not just a linear approximation occurs, but a smooth change in the position of the object’s reference points in accordance with the specified conditions.

These conditions are determined by the hierarchy of objects (that is, the laws of their interaction with each other), permitted planes of motion, maximum rotation angles, acceleration and speed values. This approach is called the method inverse kinematics of motion. It works well for modeling mechanical devices. In the case of imitation of living objects, the so-called skeletal models. That is, a certain frame is created, movable at points characteristic of the object being modeled. The movements of the points are calculated using the previous method. Then a shell consisting of modeled surfaces is superimposed on the frame, for which the frame is a set of control points, that is, it is created frame model. The wireframe model is rendered by overlaying surface textures based on lighting conditions. As the object moves, a very plausible imitation of the movements of living beings is obtained.

The most advanced animation method involves capturing the actual movements of a physical object. For example, bright light sources are attached to a person at control points and the specified movement is recorded on video or film. Then the frame coordinates of the points are transferred from the film to the computer and assigned to the corresponding reference points of the frame model. As a result, the movements of the simulated object are practically indistinguishable from the living prototype.

The process of calculating realistic images is called rendering(visualization). Most modern rendering programs are based on Backway Ray Tracing method. The use of complex mathematical models makes it possible to simulate physical effects such as explosions, rain, fire, smoke, fog. Once rendering is complete, 3D computer animation is used either as a standalone product or as individual parts or frames of the finished product.

A special area of 3D modeling in real time consists of simulators of technical equipment - cars, ships, aircraft and spacecraft. They need to very accurately implement the technical parameters of objects and the properties of the surrounding physical environment. In simpler versions, for example, when teaching driving land vehicles, simulators are implemented on personal computers.

The most advanced devices to date have been created for training to pilot spaceships and military aircraft. Several specialized graphic stations built on powerful RISC-processors and high-speed video adapters with hardware accelerators for 3D graphics. General control of the system and calculation of interaction scenarios are entrusted to a supercomputer consisting of tens and hundreds of processors. The cost of such complexes is expressed in nine figures, but their use pays off quite quickly, since training on real devices is tens of times more expensive.

Raster graphics

For raster images consisting of dots, the concept is of particular importance permissions, expressing the number of points per unit length. It is necessary to distinguish between:

· original resolution;

· screen image resolution;

· resolution of the printed image.

Original resolution. Original resolution is measured in dpi ( dots per inch – dpi ) and depends on the requirements for image quality and file size, the method of digitizing and creating the original illustration, the selected file format and other parameters. In general, the rule applies: the higher the quality requirement, the higher the resolution of the original should be.

Screen resolution. For screen copies of an image, the elementary raster point is usually called pixel. Pixel size varies depending on the selected screen resolution(from the range of standard values), original resolution and display scale.

Monitors for image processing with a diagonal of 20–21 inches (professional class), as a rule, provide standard screen resolutions of 640x480, 800x600, 1024x768, 1280x1024, 1600x1200, 1600x1280, 1920x1200, 1920x1600 pixels. The distance between adjacent phosphor points on a high-quality monitor is 0.22–0.25 mm.

A resolution of 72 dpi is sufficient for a screen copy, 150–200 dpi for printing on a color or laser printer, and 200–300 dpi for output on a photo exposure device. A rule of thumb has been established that when printing, the resolution of the original should be 1.5 times greater than raster lineature output devices. In case the hard copy will be enlarged compared to the original, these values should be multiplied by the scaling factor.

Printed image resolution and the concept of lineature. The dot size of a raster image both on a hard copy (paper, film, etc.) and on the screen depends on the method and parameters used rasterization original. When rasterizing, a grid of lines is superimposed on the original, the cells of which form raster element. The raster grid frequency is measured by the number lines per inch (Ipi) and is called lineature.

The raster dot size is calculated for each element and depends on the tone intensity in a given cell. The higher the intensity, the denser the raster element is filled. That is, if the cell contains absolutely black color, the size of the raster point will coincide with the size of the raster element. In this case, they talk about 100% occupancy. For a completely white color, the fill value will be 0%. In practice, element occupancy on a print usually ranges from 3 to 98%. In this case, all raster points have the same optical density, ideally approaching absolute black. The illusion of a darker tone is created by increasing the size of the dots and, as a result, reducing the white space between them with the same distance between the centers of the raster elements. This method is called rasterization amplitude modulation (AM).

Tone intensity(so-called lightness) It is customary to divide it into 256 levels. A larger number of gradations is not perceived by human vision and is redundant. A smaller number worsens the perception of the image (the minimum acceptable value for a high-quality halftone illustration is 150 levels). It is easy to calculate that to reproduce 256 tone levels it is enough to have a raster cell size of 256 = 16 x 16 pixels.

When outputting a copy of an image on a printer or printing equipment, the screen lineature is chosen based on a compromise between the required quality, the capabilities of the equipment and the parameters of the printed materials. For laser printers, the recommended lineature is 65-100 Ipi, for newspaper production - 65-85 lpi, for book and magazine printing - 85-133 lpi, for artistic and advertising work - 133-300 lpi.

When printing images with overlapping rasters, such as multicolor images, each subsequent raster is rotated by a certain angle. Traditional rotation angles for color printing are 105 degrees for cyan, 75 degrees for magenta, 90 degrees for yellow, and 45 degrees for black. In this case, the raster cell becomes oblique, and a resolution of 16x150=2400 dpi is no longer sufficient to reproduce 256 tone gradations with a lineature of 150 lpi. Therefore, for professional-class photographic exposure devices, a minimum standard resolution of 2540 dpi is adopted, which ensures high-quality rasterization at different raster rotation angles. Thus, the coefficient taking into account the correction for the raster rotation angle for color images is 1.06.

Dynamic range. The quality of tone image reproduction is usually assessed dynamic range (D). This optical density, numerically equal to the decimal logarithm of the reciprocal transmittance (for originals held up to the light, such as slides) or reflection coefficient(for other originals, such as printed prints).

For optical media that transmit light, the dynamic range ranges from 0 to 4. For surfaces that reflect light, the dynamic range value ranges from 0 to 2. The higher the dynamic range, the more halftones are present in the image and the better the quality of its perception. .

The relationship between image parameters and file size. It is customary to use raster graphics to illustrate works that require high precision in the reproduction of colors and halftones. However, raster illustration file sizes grow rapidly as resolution increases. A photograph intended for home promotion (standard size 10x15 cm, digitized with a resolution of 200-300 dpi, color resolution 24 bits), occupies the format TIFF with compression mode enabled, about 4 MB. A slide digitized with high resolution occupies 45-50 MB. A separated color image in A4 format occupies 120-150 MB.

Scaling raster images. One of the disadvantages of raster graphics is the so-called pixelation images when enlarged (unless special measures are taken). Since the original contains a certain number of dots, then with a larger scale their size increases, raster elements become noticeable, which distorts the illustration itself (Fig. 4). To counteract pixelation, it is customary to digitize the original in advance with a resolution sufficient for high-quality visualization when scaling. Another technique is to use a stochastic raster to reduce the pixelation effect within certain limits. Finally, when scaling, the interpolation method is used, when the size of the illustration increases not by scaling the points, but by adding the required number of intermediate points.

Figure 4 Pixelation effect when scaling a raster image

Vector graphics

If in raster graphics the basic element of the image is a point, then in vector graphics it is line. A line is described mathematically as a single object, and therefore the amount of data to display an object using vector graphics is significantly less than in raster graphics.

Line – elementary an object vector graphics. Like any object, a line has properties: shape (straight, curve), thickness, color, style (solid, dotted). Closed lines acquire the property filling. The space they cover can be filled with other objects (textures, maps) or the chosen color. The simplest open line is bounded by two points called nodes. Nodes also have properties whose parameters affect the shape of the end of the line and the nature of its connection to other objects. All other vector graphics objects are made up of lines. For example, a cube can be composed of six connected rectangles, each of which, in turn, is formed by four connected lines. It is possible to imagine the cube as twelve connected lines forming edges.

Mathematical foundations of vector graphics

Let's take a closer look at ways to represent various objects in vector graphics.

Dot. This object on the plane is represented by two numbers (x, y), indicating its position relative to the origin.

Figure 5 Vector graphics objects

Straight line. It corresponds to the equation y = kx + b . Specifying the parameters k And b, You can always display an infinite straight line in a known coordinate system, that is, two parameters are enough to specify a straight line.

Straight segment. It differs in that it requires two more parameters to describe it - for example, coordinates x 1 and X 2 beginnings and ends of the segment.

Second order curve. This class of curves includes parabolas, hyperbolas, ellipses, circles, that is, all lines whose equations contain degrees no higher than two. A second order curve has no inflection points. Straight lines are just a special case of second-order curves. The general formula for a second-order curve may look like this:

x 2 +a 1 y 2 +a 2 xy+a 3 x+a 4 y+a 5 =0.

Thus, to describe an infinite second-order curve, five parameters are sufficient. If you want to plot a curve segment, you will need two more parameters.

Third order curve. The difference between these curves and second-order curves is the possible presence of an inflection point. For example, the graph of a function at = x 3 has an inflection point at the origin (Fig. 15.5). It is this feature that makes it possible to make third-order curves the basis for displaying natural objects in vector graphics. For example, the bending lines of the human body are very close to third-order curves. All second-order curves, like straight lines, are special cases of third-order curves.

In general, the equation of a third-order curve can be written as follows:

x 3 +a 1 y 3 +a 2 x 2 y+a 3 xy 2 +a 4 x 2 +a 5 y 2 +a 6 xy+a 7 x+a 8 y+a 9 =0.

Thus, a third-order curve is described by nine parameters. The description of its segment will require two more parameters.

Figure 6 Third order curve (left) and Bezier curve (right)

Bezier curves. This is a special, simplified form of third-order curves (see Fig. 6). Bezier curve method (Bezier) is based on the use of a pair of tangents drawn to a line segment at its ends. Bezier curve segments are described by eight parameters, so it is more convenient to work with them. The shape of the line is affected by the angle of the tangent and the length of its segment. Thus, the tangents play the role of virtual “levers” with the help of which the curve is controlled.

Raster and vector graphics

Thus, choice raster or vector format depends on the goals and objectives of working with the image. If photographic color accuracy is needed, then a raster is preferable. It is more convenient to present logos, diagrams, and design elements in vector format. It is clear that in both raster and vector representation, graphics (as well as text) are displayed on a monitor screen or printing device in the form of a collection of points. On the Internet, graphics are presented in one of the raster formats that browsers can understand without installing additional modules - GIF, JPG, PNG.

Without additional plugins (add-ons), the most common browsers only understand raster formats - .gif, .jpg and .png (the latter is not yet widely used). At first glance, the use of vector editors becomes irrelevant. However, most of these editors provide export to .gif or .jpg at the resolution you choose. And it is easier for novice artists to draw in vector media - if the hand trembles and the line goes in the wrong direction, the resulting element is easily edited. When drawing in raster mode, you risk irreparably damaging the background.

Due to the features of image representation described above, for each type you have to use a separate graphic editor - raster or vector. Of course they have common features– the ability to open and save files in different formats, use tools with the same names (pencil, pen, etc.) or functions (select, move, zoom, etc.), choose the desired color or shade... However, the principles implementation of drawing and editing processes different and are determined by the nature of the corresponding format. So, if in raster editors they talk about selecting an object, they mean a collection of points in the form of an area of complex shape. The extraction process is very often labor-intensive and painstaking work. When you move such a selection, a “hole” appears. In a vector editor, an object represents a set of graphic primitives, and to select it, you just need to select each of them with the mouse. And if these primitives were grouped by the appropriate command, then it is enough to “click” once on any of the points of the grouped object. Moving a selected object exposes underlying elements.

However, there is a tendency towards rapprochement. Most modern vector editors are able to use raster images as backgrounds, or even convert parts of the image into vector format using built-in tools (tracing). Moreover, there are usually tools for editing the loaded background image, at least at the level of various built-in or installed filters. Version 8 of Illustrator is capable of loading Photoshop .psd files and using each of the resulting layers. In addition, to use the same filters, the generated vector image can be directly converted into a raster format and further used as an uneditable raster element. Moreover, all this is in addition to the usually available converters from vector to raster format with obtaining the corresponding file.

In computer graphics, at least three dozen file formats are used to store images. But only a part of them has become a “de facto” standard and is used in the vast majority of programs. As a rule, raster, vector, and three-dimensional image files have incompatible formats, although there are formats that allow you to store data of different classes. Many applications are focused on their own “specific” formats; transferring their files to other programs forces you to use special filters or export images to a “standard” format.

TIFF(Tagged Image File Format). The format is designed for storing high-quality raster images (file name extension.TIF). It is widely used and is portable across platforms. (IBM PC and Apple Macintosh), is supported by most graphics, layout and design programs. Provides a wide range of color gamuts - from monochrome black and white to 32-bit color separation model CMYK. Starting from version 6.0 in the format TIFF You can store information about masks (clipping paths) of images. Built-in compression algorithm is used to reduce file size LZW.

PSD(PhotoShop Document). Adobe Photoshop's own format (file name extension.PSD), one of the most powerful in terms of storage capabilities for raster graphic information. Allows you to remember the parameters of layers, channels, degrees of transparency, and many masks. 48-bit color encoding, color separation, and various color models are supported. The main disadvantage is that the lack of an effective information compression algorithm leads to a large volume of files.

PCX. The format appeared as a format for storing raster data in the PC PaintBrush program from Z-Soft and is one of the most common (file name extension.PCX). The inability to store color-separated images, insufficient color models and other limitations led to the loss of popularity of the format. Currently considered obsolete.

JPEG (Joint Photographic Experts Group). The format is intended for storing raster images (file name extension.JPG). Allows you to adjust the relationship between file compression rate and image quality. The compression methods used are based on removing “redundant” information, so the format is recommended to be used only for electronic publications.

GIF (Graphics Interchange Format). Standardized in 1987 as a means of storing compressed images with a fixed (256) number of colors (file name extension .GIF). Gained popularity on the Internet due to its high compression ratio. Latest format version GIF89a allows you to load images interlaced and create images with a transparent background. Limited possibilities for the number of colors determine its use exclusively in electronic publications.

PNG (Portable Network Graphics). A relatively new (1995) format for storing images for publishing on the Internet (file name extension .PNG). Three types of images are supported - color with a depth of 8 or 24 bits and black and white with a gradation of 256 shades of gray. Information compression occurs with virtually no loss, 254 alpha channel levels and interlaced scanning are provided.

WMF (Windows MetaFile). Windows operating system vector image storage format (file name extension.WMF). By definition, it is supported by all applications of this system. However, the lack of tools for working with standardized color palettes accepted in printing and other shortcomings limit its use.

EPS (Encapsulated PostScript). A format for describing both vector and raster images in Adobe's PostScript language, the de facto standard in the field of prepress processes and printing (file name extension.EPS). Since the PostScript language is universal, the file can simultaneously store vector and raster graphics, fonts, clipping paths (masks), equipment calibration parameters, and color profiles. The format used to display vector content on the screen is W.M.F. and raster - TIFF. But the screen copy only roughly reflects the real image, which is a significant drawback EPS. The actual image can only be seen at the output of the output device, using special viewing programs or after converting the file to PDF format in the Acrobat Reader, Acrobat Exchange applications.

PDF (Portable Document Format). Document description format developed by Adobe (file name extension.PDF). Although this format is primarily intended for storing entire documents, its impressive capabilities allow for efficient presentation of images. The format is hardware-independent, so images can be displayed on any device – from a monitor screen to a photographic exposure device. A powerful compression algorithm with controls for the final image resolution ensures compact files with high quality illustrations.

In computer graphics the concept is used color resolution(other name - color depth). It defines a method for encoding color information for display on a monitor screen. To display a black and white image, two bits are enough (white and black). Eight-bit encoding allows you to display 256 gradations of color tone. Two bytes (16 bits) define 65,536 shades (this mode is called High Color). With a 24-bit encoding method, it is possible to define more than 16.5 million colors (the mode is called

From a practical point of view, the color resolution of the monitor is close to the concept color gamut. It refers to the range of colors that can be reproduced using one or another output device (monitor, printer, printing press, etc.). In accordance with the principles of image formation using additive or subtractive methods, methods have been developed for dividing a color shade into its constituent components, called color models. In computer graphics, models are mainly used RGB And H.S.B.(for creating and processing additive images) and CMYK(to print a copy of the image on printing equipment). Color models are located in a three-dimensional coordinate system forming color space, since from Grossman's laws It follows that color can be expressed as a point in three-dimensional space.

Grassmann's first law (law of three-dimensionality). Any color can be uniquely expressed by three components if they are linearly independent. Linear independence is the impossibility of obtaining any of these three colors by adding the other two.

Grassmann's second law (law of continuity). With a continuous change in radiation, the color of the mixture also changes continuously. There is no color that cannot be matched infinitely close.

Grassmann's third law (law of additivity). The color of a mixture of radiation depends only on its color, but not on its spectral composition. That is, the color ( WITH) mixture is expressed by the sum of color equations of radiation:

C 1 =R 1 R+G 1 G+B 1 B ;
C 2 =R 2 R+G 2 G+B 2 B;
C n =R n R+G n G+B n B;
C sums =(R 1 +R 2 +…+R n)R+(G 1 +G 2 +…+G n)G+ (B 1 +B 2 +…+B n)B.

CIE Lab color model

In 1920, the color spatial model was developed CIE Lab (Communication Internationale de I"Eclairage - international commission for the meeting. L, a, b– designations of coordinate axes in this system). The system is hardware independent and therefore is often used to transfer data between devices. In the model CIE Lab any color is determined by lightness (L) and chromatic components: parameter a, varying in the range from green to red, and parameter b, varying from blue to yellow. Model color gamut CIE Lab significantly exceeds the capabilities of monitors and printing devices, so before displaying the image presented in this model, it must be converted. This model was developed to harmonize color photochemical processes with printing processes. Today it is the default standard for Adobe Photoshop.

RGB color model

Color model RGB is additive, that is, any color is a combination in varying proportions of three primary colors - red (Red), green (Green) blue (Blue). It serves as the basis for the creation and processing of computer graphics intended for electronic reproduction (on a monitor, TV). When one component of the primary color is superimposed on another, the brightness of the total radiation increases. The combination of the three components gives an achromatic gray color, which, with increasing brightness, approaches white. At 256 gradation levels, black corresponds to zero values RGB and for white – maximum, with coordinates (255,255,255).

HSB color model

Color model H.S.B. designed with maximum consideration for the characteristics of human color perception. It is based on the Munsell color wheel. Color is described by three components: hue (Hue) saturation (Saturation) and brightness (Brigfitness). The color value is chosen as a vector emanating from the center of the circle. The dot in the center corresponds to the color white, and the dots along the perimeter of the circle correspond to pure spectral colors. The direction of the vector is specified in degrees and determines the color shade. The length of the vector determines the color saturation. On a separate axis called achromatic, brightness is set, with the zero point corresponding to black. Model color gamut H.S.B. covers all known meanings of real colors.

Model H.S.B. It is customary to use it when creating images on a computer, simulating the working techniques and tools of artists. There are special programs that imitate brushes, pens, and pencils. Provides an imitation of working with paints and various canvases. After creating an image, it is recommended to convert it to a different color model, depending on how you intend to publish it.

CMYK color model, color separation

Color model CMYK refers to subtractive, and is used when preparing publications for printing. Color components CMY are the colors obtained by subtracting the primary ones from white:

cyan (cyan) = white - red = green + blue;

magenta = white - green = red + blue;

yellow = white - blue = red + green.

This method corresponds to the physical essence of the perception of rays reflected from printed originals. The colors cyan, magenta and yellow are called additional, because they complement the primary colors to white. This leads to the main problem of the color model. CMY – superimposing complementary colors on top of each other does not in practice produce pure black. Therefore, a pure black component was included in the color model. This is how the fourth letter appeared in the abbreviation of the color model CMYK (Cyan, Magenta, Yellow, blacK). To print on printing equipment, a color computer image must be divided into components corresponding to the components of the color model CMYK. This process is called color separation. The result is four separate images containing the same color content of each component in the original. Then, in a printing house, from forms created on the basis of color-separated films, a multi-color image is printed, obtained by overlaying colors CMYK.

Among the programs designed for creating computer two-dimensional painting, the most popular are Painter from Fractal Design, FreeHand from Macromedia, and Fauve Matisse. The Painter package has a fairly wide range of drawing and color tools. In particular, it simulates various tools (brushes, pencil, pen, charcoal, airbrush, etc.), allows you to imitate materials (watercolor, oil, ink), and also achieve the effect of a natural environment. In turn, the latest versions of the FreeHand program have rich image and text editing tools, contain a library of special effects and a set of tools for working with color, including multi-color gradient fill tools.

Among the Macintosh-based image creation programs, PixelPaint Pro from Pixel Resources is a bitmap painting and image editing package.

Among computer painting programs for graphic stations Silicon Graphics(SGI) A special place is occupied by Alias Wavefront's StudioPaint 3D package, which allows you to paint with various tools (“brushes”) in real time directly on 3D models. The package works with an unlimited number of image layers and provides 30 levels of undoing the previous action (undo), includes color correction operations and “spline brushes”, the “stroke” of which can be edited point by point like a spline curve. StudioPaint 3D supports a tablet with a sensitive pen, allowing the artist to sketch traditionally by hand, then transfer the drawing into 3D modeling or animation packages and build a 3D model from the sketch.

Adobe Photoshop

Adobe's Photoshop package occupies a special place in the broad class of programs for processing raster graphics. In fact, today it is the standard in computer graphics, and all other programs are invariably compared to it.

The main controls of Adobe Photoshop are located in the menu bar and toolbar. A special group consists of dialog boxes - tool palettes:

· The Brushes palette controls settings for editing tools. A brush enters editing mode after double-clicking on its image in the palette. CTRL-clicking destroys the brush. Double-clicking on a free field of the palette opens a dialog box for creating a new brush, which is automatically added to the palette.

· The Options palette is used to edit the properties of the current tool. You can open it not only from the menu bar, but also by double-clicking on the tool icon in the toolbar. The composition of the palette controls depends on the selected tool.

· The Info palette provides information support for display tools. It presents: the current coordinates of the mouse pointer, the size of the current selected area, the color parameters of the image element and other data.

· The Navigator palette allows you to view different parts of the image and change the viewing scale. The palette window contains a thumbnail of the image with a selected viewing area.

· The Synthesis palette displays the color values of the current foreground and background colors. The sliders on the color bar of the corresponding color system allow you to edit these parameters.

· Palette Catalog contains a set of available colors. This set can be downloaded and edited by adding and removing colors. The color tone of the foreground and background is selected from the set. The standard package of the program includes several color sets, mainly from Pantone.

· The Layers palette is used to control the display of all image layers, starting from the top one. It is possible to determine the parameters of layers, change their order, and operate on layers using different methods.

· The Channels palette is used to select, create, duplicate and delete channels, determine their parameters, change the order, convert channels into independent objects and form combined images from several channels.

· The Paths palette contains a list of all created paths. When you convert a path to a selection, it is used to form a clipping path.

· The Operations palette allows you to create macro commands - a given sequence of operations with the image. Macros can be recorded, executed, edited, deleted, or saved as files.

Filters represent a special group of image processing software. These are modules plugged into the program, often from third parties, that allow you to process an image according to a given algorithm. Sometimes such algorithms can be very complex, and the filter window can have many customizable parameters. Among the filter groups, products from the Kai's Power Tools, Alien Skin, Andromeda and others series are popular.

Currently, many illustrative graphics packages have been created that contain easy-to-use, developed and powerful vector graphics tools designed both for preparing materials for printing and for creating pages on the Internet.

To create a graphic object, you will need an illustrative vector graphics program. The quality and usefulness of vector graphics tools is determined primarily by their scaling capabilities.

Vector or illustration graphics packages have always been based on an object-oriented approach, allowing you to draw the outlines of objects and then fill them in with colors or patterns. You can reproduce these outlines very accurately at any size because they are formed using a mathematical model of points and curves, rather than as raster images - a grid filled with rectangular pixels.

One of the new features we have discovered in this product category is multi-color gradient shading. Primitives such as polygons, stars, and spirals have become common features of such packages. Linked colors allow you to replace the rose's red with yellow, changing only the base color; all associated shades will change automatically. Multi-layered, interactive color "transparencies" provide previously unattainable depth, and you can convert vector images to raster images within a vector graphics file. While yesterday's vector graphics packages only allowed you to place a raster image into your file, today's programs allow you to embed raster images, resize them, and even apply special effects and masks. This facilitates the process of obtaining the final image using multilayer graphics - combining vector and raster files necessary to create logos, printed advertisements and images for the Web.

The principles behind the latest packages completely change the way we think about vector graphics. CorelXara 1.5 takes a completely new approach to visualization, with amazing tools for creating .GIF and JPEG output files and a phenomenally fast browser plug-in for working with vector graphics. Fractal Design's Expression 1.0 package allows you to build paths from other complex vector graphics, giving you an endless variety of visual possibilities that are unattainable with other programs.

Unlike beginner-oriented desktop publishing software or photo editing programs, which typically contain the most commonly used editing tools, graphics packages for beginners tend to focus on specific tasks, such as diagramming or technical drawing. Acquiring the skills to freely draw Bezier curves is difficult even for a professional; It is no less difficult to master the basic principles of machine drawing, for example, the depiction of cuts and sections. In addition, many novice users do not understand the differences between raster and vector graphics and may not know when to use which packages. For these reasons, beginners should balance their goals with the program's capabilities and only upgrade to a full-featured painting package when they are ready.

In most cases, to create simple illustrations, it is enough for beginners to be able to work with the software tools that they may already have. Microsoft, Corel, and Lotus software packages contain drawing tools in their word processor and presentation graphics modules, as well as clipart libraries. Plus, AutoShape lets you create a wide variety of standard shapes and even diagramming symbols (which can cast shadows or even be extruded to give you three-dimensionality), and the WordArt gallery provides interesting, colorful text styles that you can use to can be used for headings or labels.

For technical tasks, let's pay attention to such diagramming programs as FlowCharter 7 from Micrografx (http://www.micrografx.com) or Visio Professional 4.5 from Visio Corp. (http://www.visio.com). If you start working in the field of CAD, then there are several packages that are quite affordable in price and capabilities, including AutoCAD LT from Autodesk (http://www.autodesk.com) or Design CAD from ViaGrafx (http://www.viagrafx .com).

To prepare drawings for small construction projects, such as a home remodel or kitchen remodel, you can use Planix and Draftix packages from SoftDesk (http://www.softdesk.com), Visual Home from Books That Work (www.btw.com), or 3D Home Architect, Edition 2 by Broderbund Software (http://www.broderbund.com/3dhome).

Corel Draw 8-9

CorelDraw always makes a strong impression. Corel included many programs in the kit, including Corel Photo-Paint. The new package has undoubtedly the most powerful tools among all survey programs, and at the same time, compared to the previous version, the interface has become simpler, and the tools for drawing and editing nodes are more flexible (Fig. 9). However, when it comes to new features, in particular preparing publications for the Web, here CorelDraw is inferior to CorelXara. CorelDraw's work with CMYK colors leaves much to be desired. The colors in GIF and JPEG files were noticeably different from the Matchprint proof, while FreeHand produced the same colors on screen, in Web files, and in printers.

No problem. CorelDraw's artistic text design capabilities are impeccable, and the default settings for letter spacing when placing text along a curve do not require settings to prevent letter overlap - unlike Canvas and FreeHand. The Magnifier tool is second to none - it allows you to get a variety of special effects, including the ability to zoom in on just a portion of an image and automatically adjust text colors based on the background color.

You can crop images, apply color filters, and give raster images the appearance of a curved page using 2D and 3D effects and PhotoShop plug-ins. When you needed to edit pixels, CorelDraw automatically switched you to Corel Photo-Paint, where you could edit the file and save it directly in CorelDraw. However, beyond basic scaling and dynamic sizing capabilities, CorelDraw does not include special tools for preparing technical illustrations, like Smart Mouse in Canvas or copying arrays in Designer.

Not everything is so smooth. The ability to implement CMYK models - an area CorelDraw has struggled with - is still a concern, although the program can now work with Kodak's CMS color management system. First, to maintain compatibility with previous versions of CorelDraw, you need to turn off Kodak color correction every time you open CorelDraw in the View menu. Second, unless your printers are on the limited list of approved peripherals, there is no guarantee that a matching generic driver will always be available. CorelDraw exports colors the same way they appear when color correction is turned off, so to get a good image on a Web page, it is best to select the oversampling mode when exporting raster files. Corel viewer. CMX is painfully slow, and CMX files are larger than CDR files, which is a big deal when working on the Web. Barista, Corel's Java-based format for displaying documents on the Web, is a promising technology, but currently it's best used only for simple documents.

Despite its powerful tools, CorelDraw suffers from certain shortcomings. CorelDraw's wide range of tools makes it exceptionally useful for drawing, but the unnatural appearance of printed pages and Web pages limits its use. If you want to get the most out of CorelDraw, we recommend waiting for the next version, regularly checking the Corel Web site for new releases, and starting with a phone call to technical support to ensure your color correction settings are correct.

Micrografx Designer 7

Micrografx Designer 7, an easy-to-use, albeit small program that handled most tests with ease, also deserves special mention for its excellent technical illustration tools. Designer 7, along with FlowCharter 7 and Picture Publisher 7, forms the core of the Micrografx Graphics Suite and is one of the least expensive programs in this review. Designer's drawing tools are some of the easiest to learn and use. Like CorelXara, Designer doesn't have a text editing window, forcing you to constantly edit it in full WYSIWYG mode. Moving between layers is very awkward and although you can use multiple pages of different formats, moving objects between pages requires an editing buffer.

Powerful tools. The unique Reference Point tool allows you to set restrictions on x- and y-axis distances and rotation angles, or force all objects to be placed at a certain distance from a certain point. Designer 7 has many features—like iterative color mixing—not found in previous versions, but we still found a few major shortcomings. Snapping to guides only occurred when resizing an object, not when dragging it.

However, the Designer package comes with some interesting raster filters and effects, and it allowed us to edit pixels in Picture Publisher using OLE technology. Designer produced good GIFs with color blending, GIFs without color blending with images that resembled wicker baskets, and abnormal JPEGs with images that looked like bubbles. Designer also allows you to attach URLs to objects for use with the Micrografx QuickSilver 3 browser plug-in. What makes QuickSilver special is that you can assign specific properties to vector graphics objects. Designer 7's simple interface makes it easy to handle many typical office graphics jobs, but fundamental tool limitations and very limited capabilities for four-color CMYK printing may discourage professional graphic artists from purchasing it. But if you need a powerful technical drawing tool, or want to interactively add content to your Web pages without having to code, this might be the package for you.

Adobe Illustrator 7

Adobe Systems has finally presented the next version of its Adobe Illustrator 7.0 package. The new version is one of the most expensive of the standalone vector graphics programs reviewed in this review. Illustrator's functionality today is so inferior to CorelDraw, not to mention Macromedia FreeHand 7, that we wouldn't recommend it for professional graphic artists until Adobe releases a substantially modernized version. Figure 10 shows the documents window in this editor.

Glorious past. A veteran of vector graphics, Illustrator was once a towering achievement in the field and served as the model on which all the programs presented in this review are based. But since then, every new product has had some improvement. For example, Macromedia FreeHand does a better job of importing EPS and AI files while maintaining the high CMYK color accuracy that Illustrator has always had. CorelDraw has long raised the bar with gradient shading, true layers, Boolean operations, and special effects in its packages. Canvas 5 features pixel-level raster image editing and a workspace of nearly 140 m2, compared to Illustrator's 0.2 m2 workspace. Micrografx Designer provides superior drawing tools, integrates with Windows and Microsoft Office, and includes tools for preparing technical illustrations, while CorelXara provides true transparency for vector objects and the ability to embed raster images. In turn, Fractal Design Expression using the Skeletal Strokes tool allows you to obtain the most unusual effects and modify the image.

Unfortunately, Illustrator's relatively limited feature set doesn't mean it's easy to use. It's estimated that a gradient shading of a rainbow image that requires 5 clicks in CorelDraw would take 67 clicks in Illustrator because you'll have to create transitions for each pair primary colors.

Basic tools. Illustrator does not allow you to export .GIF and JPEG files for use on the Web. And while color print quality remains Illustrator's biggest strength, you'll love FreeHand's CMYK color processing capabilities just as much (and the same version of FreeHand can run on both Windows and Mac). There are also issues to be aware of when using Illustrator with S3-based graphics cards (Adobe warns users about this). Illustrator, which once paved the way for other graphics packages, has faded into the background today. Until Adobe seriously redesigns it, we recommend looking elsewhere. If you're still working in Illustrator and files created with it, consider FreeHand as an alternative.

Macromedia FreeHand 7

Macromedia FreeHand 7 impresses with impeccable quality of screen output and four-color CMYK printing and the availability of several formats for the Web. Because FreeHand always displays colors as they will appear when printed, it was the only program in our review that did not allow the creation or assignment of colors that would be very different when printed from the corresponding colors on the screen. The FreeHand color listing only includes colors that you have used or created. The program allows you to select colors from several libraries, including Pantone and Hexachrome for printing, and from the Web palette, optimized for both Mac and PC.

FreeHand's tools for drawing and working with text meet the necessary requirements, but are somewhat limited. The FreeHand interface favors editing nodes rather than editing the entire object. Each of the operations of scaling, rotating, mirroring and warping - performed in CorelDraw by manipulation in the object's working window - requires a separate tool from the FreeHand toolkit. When you select an object, its points (nodes) are always available for direct editing, but this means that you see the nodes and paths of the object, and not its “finished” view.

Corel Xara 1.5

Working with CorelXara is like sitting behind the wheel of an elegant red Ferrari convertible in a beautiful spring park. The simple and clear interface of CorelXara will first of all make you wonder: why is it considered that using illustrative graphics packages is so difficult?

CorelXara 1.5 is one of the new generation programs discussed in this review. It serves primarily to create a graphic image on a page at a time and form a block of text at a time. The program allows you to do things you could only dream of with drawings, gradient fills, images and transparencies. Although Corel advertises CorelXara 1.5 as a complement to CorelDraw 7 for creating Web graphics, CorelXara's inherent performance, Web capabilities, and specialized tools are superior to CorelDraw in many ways.

With the scaling capabilities of vector graphics and raster image textures, 2D objects begin to look more and more like 3D objects. Draw the object. Apply a texture (bitmap) or paint over it (material). Determine the level of transparency. Then move the image and edit it to your liking.

What is behind the external simplicity. CorelXara's interface is elegant and simple. Icons in the top row provide access to full-color visual sets of colors, fills, shading, bitmaps, fonts, and graphic inserts (cliparts).

CorelXara makes it easy to manage color by creating families of related shades. Change the base color from blue to green and your subject changes the entire gamut of hues. Note that CorelXara does not include specific tools for technical illustration, and you must enter the text yourself because CorelXara does not provide import filters for word processing programs. However, this program was the only one reviewed that allowed you to place multiple lines of text along one curved guide, and its collection of fonts not only contains their names, but also shows the typefaces.

We offer a summary table of the main characteristics of the most popular programs for working with vector graphics:

Miracles for the Web. Today's most powerful Web graphics tool, the CorelXara plug-in for Netscape Navigator and Microsoft Internet Explorer, allows you to zoom in up to 25,000% directly from the browser. Thanks to file compactness and high performance, vector graphics have bright prospects in the field of Web page development.

CorelXara can't do it all, but in some ways it's unrivaled. If you prepare complex original designs, are just getting started with art packages, or enjoy working with transparent layers, CorelXara is a good addition to your toolbox.

We offer a summary table of the main characteristics of the most popular programs for working with vector graphics.

	Adobe Illustrator	Canvas 5	Corel Draw	Corel Xara 1.5	Fractal Design Expression	Macromedia FreeHand 7	Micrografx Designer 7
functionality
artistic illustration	acceptable	acceptable
technical illustration
color print					acceptable
preparing web pages					acceptable
ease of use
artistic illustration		acceptable
technical illustration
color print
preparing web pages
working with color
color models			CIE lab CMY CMYK HSB HSL RGB YIQ

Category artistic illustration characterizes the diversity and versatility of drawing tools. In addition, software products must be able to accurately import and export a variety of file types.

Category color print reflects the software's color matching capabilities and the quality of the resulting prints. Illustrative graphics programs must identify areas where color pairs meet, perform spot color conversions to process colors, and precise color separations.

On personal computers, three packages occupy the main market share of 3D graphics processing software. They work most efficiently on the most powerful machines (two- or four-processor Pentium II/III, Xeon configurations) running the Windows NT operating system.

The Kinetix 3D Studio Max program for creating and processing three-dimensional graphics was originally created for the Windows platform. This package is considered “semi-professional”. However, its resources are quite sufficient for developing high-quality three-dimensional images of inanimate objects. Distinctive features of the package are support for a large number of 3D graphics hardware accelerators, powerful lighting effects, and a large number of add-ons created by third-party companies. The comparative undemanding nature of hardware resources allows it to work even on mid-level computers. At the same time, in terms of modeling and animation, the 3D Studio Max package is inferior to more developed software.

Microsoft's Softimage 3D was originally designed for workstations. SGI and only relatively recently was converted to the Windows NT operating system. The program is distinguished by rich modeling capabilities and the presence of a large number of adjustable physical and cinematic parameters. A high-quality and fairly fast Mental Ray module is used for rendering. There are many add-ons released by third parties that significantly expand the functionality of the package. This program is considered the “de facto” standard in the world of specialized graphics stations SGI, and on the platform IBM PC looks a little heavy and requires powerful hardware resources.

The most revolutionary in terms of interface and capabilities is the Maua program, developed by a consortium of well-known companies (Alias, Wavefront, TDI). The package exists in versions for different operating systems, including Windows NT. Maua's tools are divided into four groups: Animation (animation), Modeling (modeling), Dynamic (physical modeling), Rendering (visualization). A convenient, customizable interface is made in accordance with modern requirements. Today Maua is the most advanced package in the class of tools for creating and processing 3D graphics for personal computers.

All areas of application - be it engineering and science, business and art - are the scope of computer graphics. The growing potential of PCs and their sheer number of approximately 100 million PCs provides a tempting base for investment and growth. It is unknown how long the trend of capital investment doubling will last, especially driven by prices, but a steady 10% annual increase is expected over the next 5 years. Today, companies specializing in graphical user interfaces, object-oriented programs, virtual reality and parallel process software are especially attractive to investors.

According to the increase in the number of graphic terminals from 100 in 1964 to 50,000 in 1977, and already in 1994, 3 million workstations and 60 million PCs are used in the USA alone. Computer graphics today has an industrial base estimated at $36 billion, which provides jobs for about 300 thousand specialists. It continues to lead the way in how we interact with computers and access information. We are entering a new era of empowering graphics systems to navigate the information superhighway.

Computer Science: Basic Course/S.V. Simonovich and others - St. Petersburg: “Peter”, 2001.
Systems and means of informatics: Issue 4. – M.: “Nauka”, 1993.
Informatics: Workshop on computer technology / edited by I.V. Makarova. – 2nd edition. – M.: “Finance and Statistics”, 1998.
Lavel. Graphics. Raster and vector graphics: http://win-www.klax.tula.ru/~level/graphics/predgrph.html
Vector graphics: http://imped.vgts.ru/polygraph/vektor.html
About vector and raster graphics: http://flashmaker.8m.com/help/html/02basics2.html

There are methods for calculating procedural effects (Procedural Effects) and the interaction of particle systems (Particle System). However, their full use requires enormous computing resources, and therefore simplified versions are usually used in personal computers.

This review is based on software as of 1999; subsequent versions are not included in the review.

N/A - not applicable. This product does not provide this capability.

Object from the ClipArt collection

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Computer graphics: what is it?

The simplest thing is science. In addition, this is one of the branches of computer science. He studies how to process and format graphics using a computer.

Computer graphics lessons today exist in both schools and higher education institutions. And today it is difficult to find an area where it would not be in demand.

Also to the question: “What is computer graphics?” - we can answer that this is one of many areas of computer science and, in addition, it is one of the youngest: it has existed for about forty years. Like any other science, it has its own specific subject, goals, methods and objectives.

What problems does computer graphics solve?

If we consider this in a broad sense, we can see that computer graphics tools allow us to solve the following three types of problems:

1) Translation of a verbal description into a graphic image.

2) The task of image recognition, that is, translating a picture into a description.

3) Editing graphic images.

Directions of computer graphics

Despite the fact that the scope of application of this area of computer science is undoubtedly extremely wide, we can highlight the main areas of computer graphics, where it has become the most important means of solving emerging problems.

Firstly, the illustrative direction. It is the broadest of all, as it covers tasks ranging from simple data visualization to the creation of animated films.

Secondly, a self-developing direction: computer graphics, the topics and possibilities of which are truly limitless, allows you to expand and improve your skills.

Thirdly, the research direction. It includes the depiction of abstract concepts. That is, the use of computer graphics is aimed at creating an image of something that has no physical analogue. For what? As a rule, in order to show the model for clarity or to track changes in parameters and adjust them.

What types of computer graphics are there?

Once again: what is the computer branch of informatics, which studies methods and means of processing and creating graphic images using technology. There are four types of computer graphics, despite the fact that there are a huge number of different programs for processing images using a computer. These are raster, vector, fractal and 3-D graphics.

What are their distinctive features? First of all, types of computer graphics differ in the principles of illustration formation when displayed on paper or on a monitor screen.

Raster graphics

The basic element of a raster image or illustration is a dot. Provided that the picture is on the screen, the point is called a pixel. Each pixel in the image has its own parameters: color and location on the canvas. Of course, the smaller the pixels and the greater their number, the better the picture looks.

The main problem with a raster image is the large amount of data.

The second disadvantage of raster graphics is the need to enlarge the picture in order to see the details.

In addition, with strong magnification, the image becomes pixelated, that is, it is divided into pixels, which significantly distorts the illustration.

Vector graphics

The elementary component of vector graphics is a line. Naturally, raster graphics also contain lines, but they are considered as a collection of points. And in vector graphics, everything that is drawn is a collection of lines.

This type of computer graphics is ideal for storing high-fidelity images, such as drawings and diagrams.

The information in the file is stored not as a graphic image, but in the form of coordinates of points with the help of which the program recreates the drawing.

Accordingly, one of the memory cells is reserved for each point on the line. It should be noted that in vector graphics, the amount of memory occupied by one object remains unchanged and does not depend on its size and length. Why is this happening? Because a line in vector graphics is specified in the form of several parameters, or, more simply, by a formula. Whatever we do with it in the future, only the parameters of the object will change in the memory cell. The number of memory cells will remain the same.

Thus, we can come to the conclusion that vector files, compared to raster files, take up much less memory.

3D graphics

3D graphics, or three-dimensional graphics, studies methods and techniques for creating three-dimensional models of objects that closely resemble real ones. Such images can be viewed from all sides.

Smooth surfaces and various graphic shapes are used to create three-dimensional illustrations. With their help, the artist first creates the frame of the future object, and then the surface is covered with materials that are visually similar to the real thing. Next, they make gravity, lighting, atmospheric properties and other parameters of the space in which the depicted object is located. Then, provided that the object is moving, the trajectory and its speed are specified.

Fractal graphics

A fractal is a pattern consisting of identical elements. A large number of images are fractals. For example, the Koch snowflake, the Mandelbrot set, the Sierpinski triangle, as well as the Harter-Heitschey “dragon”.

A fractal pattern can be constructed either using some algorithm or by automatically creating an image, which is carried out by calculations using given formulas.

Image modification occurs when changes are made to the structure of the algorithm or coefficients in the formula are changed.

The main advantage of fractal graphics is that only formulas and algorithms are saved.

computer graphics

However, it should be noted that the identification of these areas is very conditional. In addition, it can be detailed and expanded.

So, let's list the main areas of computer graphics:

1) modeling;

2) design;

3) display of visual information;

4) creation of a user interface.

Where is computer graphics used?

Three-dimensional computer graphics are widely used in engineering programming. Computer science primarily came to the aid of engineers and mathematicians. Three-dimensional graphics are used to model physical objects and processes, for example, in animation, computer games and cinema.

Widely used in the development of printing and multimedia publications. Very rarely, illustrations made using raster graphics are created manually using computer programs. Often, scanned images that the artist has made on photographs or paper are used for this purpose.

In the modern world, digital photo and video cameras are widely used to input raster photographs into a computer. Accordingly, the vast majority of those intended for working with raster graphics are not focused on creating images, but on editing and processing.

Raster images are used on the Internet if there is a need to convey the entire color gamut.

But programs for working with vector graphics, on the contrary, are most often used for the purpose of creating illustrations rather than for processing. Such tools are often used in publishing houses, editorial offices, design bureaus and advertising agencies.

Using vector graphics, it is much easier to solve design issues that are based on the use of simple elements and fonts.

Undoubtedly, there are examples of highly artistic vector works, but they are the exception rather than the rule, for the simple reason that preparing illustrations using vector graphics is extremely difficult.

For automatic analysis using mathematical calculations, software tools have been created that work with factorial graphics. It is in programming, and not in design or drawing, that the creation of a factorial composition consists. Factorial graphics are rarely used to create an electronic or printed document, but they are often used for entertainment purposes.

Direction	Purpose	Software
Scientific	Visualization of scientific research objects, graphical processing of calculation results, conducting computational experiments with a visual presentation of their results.
Business	Creation of illustrations used in drawing up illustrations of statistical reports, etc. Used in the work of institutions.	Spreadsheets
Design	Creation of flat and three-dimensional images. Used in the work of design engineers.	Computer-aided design (CAD) systems
Illustrative	Creation of arbitrary drawings and drawings.	Graphic editor
	Create realistic images. Used to create commercials, cartoons, computer games, video tutorials, video presentations, etc.	Graphic editors (with complex mathematical apparatus)
Computer animation	Creating moving images on the monitor screen. The word "animation" means "animation."

Three-dimensional image and raster surfaces. Types of computer graphics. Computer graphics is a branch of computer science that studies the means and methods of creating and processing graphic images using computer technology. Using multiprocessing

Pixel graphics

Fractal graphics

3D graphics

-graphic arts

Infographics

Corel Draw 8-9

Micrografx Designer 7

Adobe Illustrator 7

Macromedia FreeHand 7

Corel Xara 1.5

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Similar documents

Computer graphics: what is it?

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Raster graphics

Vector graphics

3D graphics

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