15.3. tools for working with raster graphics
Software tools for creating raster images
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 its turn, latest versions FreeHand programs 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 Silicon Graphics (SGI) graphics stations, 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 three-dimensional 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.
Raster image hardware
The hardware used to obtain digital raster originals mainly includes scanners and digital cameras. Other devices, such as digital video cameras and television frame capture adapters, often play a supporting role in computer graphics. To create images “by hand”, graphics tablets are used, on which you draw with a special electronic pen.
Based on the method of image perception, scanners are divided into two groups: devices with electron photomultiplier tubes (PMTs) and devices using charge-coupled devices (CCDs, abbreviated as CCD). Scanners with photomultipliers are called drum scanners - a transparent drum is placed inside the device, on which the original (reflective or translucent) is attached. Then the drum begins to rotate at high speed. The scanning head has a powerful light source with a focused beam and photomultiplier tubes, which move along the longitudinal axis of the drum. The reflected or transmitted light flux enters the PMT (usually there is one PMT per channel) through a precision mirror scanning system. The accumulated charge of the photomultiplier is converted into a digital value by a high-bit analog-to-digital converter. Since the process up to this point is essentially analog, it is possible to achieve very high dynamic range values. That is, the original is correctly digitized in both light and dark areas. The output resolution of the original reaches 5000-6000 dpi. You have to pay for perfect quality - drum scanners are extremely expensive and demanding in terms of operating conditions.
Other scanners are CCD devices. Unlike photomultipliers, charge-coupled devices are a photodetector made of silicon elements combined into a line. Each photosensitive element has the ability to accumulate charges in proportion to the number of photons striking it. During the exposure, a matrix of charges appears, proportional to the brightness of the original image. Vertical scanning is carried out by moving either the entire CCD line using a stepper motor, or by moving the original. Resolution is determined by the number of optical elements per unit length. In household-class devices this is 300-600 elements per inch, professional - 1200-3000. Software interpolation of optical resolution does not provide any real improvement in the quality of digitization. The dynamic range of CCD devices is lower than that of PMTs because silicon elements have a worse signal-to-noise ratio.
High-precision CCD scanners additionally use: a mirror scanning system in both coordinates with compensation for distortions at the edges of the original, several CCD lines, color temperature-stable lighting lamps, multi-digit digital-to-analog converters, and elements made on CM05 plates. Such devices are close to drum scanners in terms of digitization quality, and are much more affordable in cost.
Structurally, drum scanners are made with a vertical or horizontal drum, removable or non-removable. CCD scanners can be sheet-fed, flatbed, projection, hand-held, and so-called slide (for scanning originals “through the light”).
For computer graphics purposes, it is not so much the scanner resolution (it may not exceed 300 dpi) that is important, but rather a good dynamic range. For scanning in reflected light, it is desirable to have a dynamic range of at least 2, and for transmission scanning - at least 3.5.
The basis of digital cameras is a CCD matrix, consisting of a two-dimensional array of elements. For the purposes of electronic publication and non-professional use, the sufficient number of elements on the matrix is about 1.5 million. Semi-professional cameras must have a matrix resolution of at least 2 million elements, professional cameras - 2.5-3 million. Images digitized with their help can be used to prepare printed publications. The optical system of professional-grade digital cameras must provide a resolution of at least 110-120 pairs of lines per inch.
Graphic tablets are a coordinate two-dimensional electronic grid, each element of which is capable of receiving and transmitting a number of signals from an electronic pen. These signals include: coordinates of the point of contact of the pen with the tablet, pressure force, tilt angle, speed of passage (that is, exposure time) and a number of others. Then, through software conversion, the resulting data is displayed on the screen in the form of lines, strokes and other artistic means of creating images. Having sufficient skill in working with a graphics tablet, it is possible to very accurately imitate various painting techniques - oil painting, charcoal drawing, airbrush, pencil, etc.
Raster graphics processing program 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 (Fig. 15.17).
The main controls of Adobe Photoshop are located in the menu bar and toolbar. A special group consists of dialog boxes - tool palettes. Next, we will look at the functions of the listed tools.
The initial receipt of the original occurs either through the File menu with the Open command, or with the Import command. Import refers to receiving an image from an external source - a scanner, a digital camera. Communication of the graphic editor with external devices provided through the TWAIN software interface, which sets a standard for data exchange parameters with image sources.
Before you begin operations with the original image, you should understand its parameters. To do this, use the Image > Image Size command to open the Image Size dialog box. The Dimension and Print Size groups show the width and height of the original in pixels and centimeters, respectively, as well as the resolution (in pixels per inch - ppg). The size and quality of the image depend on the set values. For the purposes of electronic publication, it is better to set the resolution to 72 ppi; for subsequent printing, choose the resolution based on the formula ppi = 1.5 × lpi, where lpi is the screen lineature set on the output device. For devices that support stochastic FM rasterization, instead of Ipi, you need to know their resolution in dpi. It is better to set the image size on a scale of 1:1 in relation to what will be used in the publication, or slightly larger.
Rice. 15.17. Working window of the Adobe Photoshop graphic editor
The toolbar (Fig. 15.18) is one of the main tools for working with images. Most of the tools presented on the panel have alternative options. Their icons are marked with a small triangle (expand button). If you hold down the mouse button on such an icon, a line of icons with tool options will open.
To work with objects, there is a group of icons that combines the Area, Lasso, Move, and Magic Wand tools. Using the Area and Lasso tools, select an area of the image bounded by a geometric shape. The Magic Wand tool samples an area based on color (or achromatic) matching within user-defined gamut boundaries. These tools are used to perform clipping operations - tracing the contours of objects in the image. Use the Move tool to move selected areas and copy them.
Full screen mode
Rice. 15.18. Adobe Photoshop 5.0 Toolbar
The next group of tools is for drawing and retouching. It includes Airbrush, Brush, Pencil, Eraser, Stamp, Finger and separate retouching tools - Dodge, Burn, Sponge, Blur, Sharpen. The first four tools simulate the work of their real counterparts. The Stamp tool allows you to perform stamping - copying selected areas of the image with each mouse click. The Finger tool simulates the shift of wet paint (washing) - a technique used by artists when writing in oil, gouache, and ink. Tools with alternate selection Sharpness/Blurry allow you to change these options to separate areas image, and the Dodge/Burn/Sponge tools are used to locally adjust brightness and color saturation.
The third group of tools (Pen, Text, Line, Fill, Gradient, Eyedropper) is designed for creating new objects. The pen (and alternative tools) allows you to draw smooth, curved paths. Use the Text tool to make inscriptions. The Line tool is used to draw straight segments. Using the Fill and Gradient tools, you fill selected areas of the image with one color, or with a smooth transition between colors. The Eyedropper tool is used to precisely determine the color at any point in the image and use it as a reference for the panel tools.
The last group includes tools for managing image viewing. The Hand tool moves the visible area across the image, and the Scale tool is intended to enlarge/reduce the image in the visible area.
At the bottom of the toolbar there are elements for working with color, masks, and the form of displaying program controls. The color control panel shows the primary background and foreground colors. In the lower left corner there is an icon, clicking on which sets the default colors. The Mask control allows you to work in Standard or Quick mask modes. Finally, the display mode control allows you to switch between Standard mode, Advanced (the title bar of the program window is hidden) and Full (the menu bar is collapsed and placed as a button at the top of the toolbar).
Tool palettes are special types of dialog boxes. They are used to configure the parameters of basic tools and perform some operations with the image. There are a total of ten tool palettes in Adobe Photoshop 5.0.
The display of palettes is controlled from the menu Window > Hide.../Show... Unused palettes can be removed from the screen by clicking on the close button. By clicking the collapse button, the palette is reduced to the size of a line with tab spines. To the right, below the title bar, the palette window has a menu button that, when clicked, provides access to a context menu for adjusting palette options. Some palettes have command buttons, drop-down lists, input fields, and other controls. The purpose of a specific control is explained by a tooltip that appears when the mouse pointer hovers over the element of interest.
Palettes can be moved around the screen by dragging and dropping. New palettes are created by “assembling” existing elements. To do this, pick up the spine of one of the palette tabs with the mouse pointer and drag it into the window of another palette. If a tab is placed on a free field of the screen, it is converted into an independent palette.
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.
The Catalog palette 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 chosen 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 layers of the image, starting with 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 specified sequence of operations with an 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, popular products are Kai's Power Tools, Alien Skin, Andromeda and others.
Rice. 15.19. KPT Texture Explorer component from Kai's Power package
Tools is designed to generate textures
Raster image files come in a variety of formats (several dozen). Each format has its own positive qualities that determine the advisability of its use when working with certain applications.
For the Windows 9x operating system, the most typical format is Windows Bitmap. Files of this format are named extension .BMP. This format is universal and is de facto standard for Windows applications. If a graphics program is designed to run on Windows 9x, it may not be able to export or import files in this format. A characteristic disadvantage of the Windows Bitmap format is the large file size due to the lack of image compression.
Recently, varieties of the BMP format have appeared that have the property of compressing information, but these formats are not supported by all Windows applications.
For Web documents circulating on the Internet, file size is very important, since the speed of access to information depends on it. Therefore, when preparing Web pages, two types of graphic formats are used that provide the most dense compression.
To store multicolor irregular images (photos), the JPEG format is used, the files of which have the extension .JPG. This format is different in that it provides data storage with a huge degree of compression, but at the expense of losing some information. If the file was recorded in the .JPG format, then after unpacking the resulting file may not match the original one, although this is hardly noticeable in illustrations such as color photographs. The amount of information loss can be controlled when saving the file. If we are talking about reproducing an illustration on the screen (but not on paper), the loss of up to 90% of the information has little effect on the quality of photographs.
In addition to the JPEG format, the GIF format is used on the Internet. This is the most “dense” of the graphic formats that do not have any loss of information. Files in this format have the extension .GIF. Low-color images, such as hand-drawn illustrations, are stored and transmitted in this format. (By the way, the fewer colors an image has, the worse the effect of using the JPEG format. The JPEG format shows the worst results on two-color black and white images.) The GIF format has very interesting features that allow you to create unusual effects: background transparency and image animation.
All advanced raster graphics editors are capable of loading and saving images in major graphics formats. Thus, they can be used to convert images from one format to another.
The basic requirements for image quality are imposed in printing. In this area, a special TIFF format is used. Files in this format have the extension .TIF. They provide not only a good compression ratio, but also the ability to store additional information in invisible auxiliary layers - channels - in one file. Thus, in the standard Imaging program included in Windows 98, the most interesting opportunities for adding annotations and notes to a drawing are implemented only when working with images in the TIFF format. In the other listed formats, you cannot create a layer to store information not directly related to the image.
Graphic editor– these are computer tools for obtaining and processing graphic images: drawings, pictures, drawings, diagrams, graphs, etc., which are obtained on the monitor screen and can be printed.We draw your attention to the fact that modern graphic editors, as a rule, have the ability to work with both raster and vector objects. For example, use Bezier curves and text symbols in raster editors. However, the primary focus on working with a certain type of graphics remains.
Editors for working with vector graphics:
Adobe Illustrator allows you to create vector images of any level of complexity using standard drawing tools and color management capabilities in this area. A clear interface and easy access to all application functions provide a professional level of control over the entire graphics creation process.
Corel Draw– one of the most powerful packages designed for creating vector graphics. Using CorelDraw tools, you can create illustrations of varying complexity, booklets, logos, etc. The program has tools for editing curves created with the mouse.
Macromedia FreeHand– a unique multi-page environment for creating complex illustrations and layouts for publication in print. Unlike Adobe Illustrator, the program supports working with multi-page documents, which allows it to be used for layout. Starting from the eleventh version of the editor, you can insert SWF videos into a document.
Inkscape is a freely distributed vector editor. It has flexible drawing tools, a powerful tool for working with text, and allows you to use Bezier and Cornu curves.
Editors for working with raster graphics
ADOBE PHOTOSHOP is the undisputed leader among professional graphic editors due to its wide range of capabilities, high efficiency and speed of work. This editor has all the necessary tools for creating, correcting, editing and preparing images for printing.
The main purpose of the program is to create photo realistic images, work with color images, retouching, color correction, collaging, etc. Adobe Photoshop has all the tools for working with bitmap images with the ability to work with multi-layered images.
PAINT- a simple raster graphics editor from Microsoft, part of the Windows operating system. Features an intuitive and innovative user interface. IN new version Paint.NET now provides layering capabilities, as well as infinite undo, special effects, and a wide variety of other useful tools.
COREL PHOTO-PAINT designed for processing raster photographic images. With its help, you can professionally prepare images for publication, both in print media and on the Internet, also in PDF format. It has tools for creating non-standard program interfaces, Web graphics, creating images based on montage, collage, drawing with brushes and ready-made objects.
It is not as popular as Adobe Photoshop, but is comparable to it in terms of technical capabilities. GIMP- a freely distributed graphic raster editor that supports more than thirty image formats, contains tools for working with layers, masks, filters and blending modes. The program's arsenal has a huge range of tools for color correction and processing of any photographs and images. The functionality of the graphics editor can be supplemented with numerous plugins and extensions written specifically for GIMP. Usually they are not created by famous companies, but by ordinary programmers, but despite this, some plugins have no analogues even in famous programs for drawing and photo processing.
GIMP supports working with filters, brushes, gradients and palettes. Brushes can be vector, raster and animated. There is support for Photoshop brushes.
Everyone uses image editors differently. Some edit photographs, others draw, and others make advertising materials. Each task requires a different interface.
GIMP supports graphics tablets and other input devices, allowing you to reconfigure the interface to suit the specific needs of any creator. For example, you can easily reassign any hotkeys without even going into the settings menu.
GIMP is a program created for millions. To process photos, it has created numerous tools, filters with a user-friendly interface and informative panels. Artists will enjoy working with brushes that can respond to pressure, direction and speed of movement across the canvas.
As you know, it’s the little things that create the overall picture; there are plenty of little “conveniences” here. For example, the first time you launch GIMP, it will detect the language of your operating system and will communicate with you in your native language.
It just so happens that GIMP is a free program. This means that it is being developed by a team of professionals; enthusiasts who work on a voluntary basis.
GIMP, unlike Photoshop, is a completely free graphics editor, and thanks to the GNU GPL license under which it is created, it can be copied and distributed without any restrictions. It can be used both in educational institutions and in any commercial organizations.
Key terms
Computer graphics is a field of computer science that deals with the creation, storage and processing of various images (drawings, drawings, animations) on a computer.
Raster graphics– a method of representing images as a collection of individual dots (pixels) of different colors or shades.
Vector graphics- a way of representing objects and images, based on a mathematical description of elementary geometric objects, usually called primitives, such as points, lines, splines, Bezier curves, circles and circles, polygons.
Pixel– the smallest element of the image, dot.
Image Resolution- the degree of detail of the image, the number of pixels (dots) allocated per unit area.
Physical Image Size– the height and width of the image in pixels (for display on the screen) or in length units (millimeters, centimeters, inches) – for printing on paper.
Color model- description of color shades by mixing several primary colors.
File format- the structure of the file, which determines the way it is stored and displayed on the screen or when printed. The file format is usually indicated in its name, as a part separated by a dot (usually this part is called the file name extension).
A list of key terms is provided at the end of each module. They are designed to allow the student to test their understanding and define each term.
Teachers use a list of terms during oral questioning.
All key terms are also defined in a glossary, at the end of the course where they are defined, and in an index that helps you find where they are described.
Brief summary
Computer graphics is a field of computer science that deals with the creation, storage and processing of various images (drawings, drawings, animations) on a computer.
Computer graphics are divided into vector and raster.
Raster is a method of representing an image as a collection of individual dots (pixels) of different colors or shades.
In vector graphics, all images are described in the form of mathematical objects - contours, i.e. the image is divided into a number of graphic primitives - points, straight lines, broken lines, arcs, polygons.
Both of these methods of encoding graphic information have their own characteristics and disadvantages.
The degree of detail in the image, the number of pixels (dots) allocated per unit area is called resolution.
The physical size of an image can be measured in both pixels and length units (millimeters, centimeters, inches). It is set when the image is created and is stored with the file.
Color models describe color shades by mixing several primary colors. Any color can be decomposed into shades of primary colors and designated by a set of numbers - color coordinates.
RGB color model (Red (red), Green (green), Blue (blue)).
To describe a specific shade, you need to describe in brackets the amount (intensity) of each of the primary colors: first red, then green, then blue. For example, (240, 160, 25) is orange.
CMYK color model (Cyan (cyan), Magenta (magenta), Yellow (yellow), Black (black)).
The model is used to obtain a printing impression. HSB color model
Model HSB (H - Hue (hue), S - Saturation (saturation), B - Brightness (brightness))
There are many programs designed to work with raster graphics.
The simplest raster editors include PaintBrush, Paint, Painter, which allow you to directly draw simple raster images.
The main class of raster graphics editors is designed for processing ready-made raster images in order to improve their quality and create your own from existing ones using some effects. Such editors include such powerful programs as Adobe Photoshop, Corel PhotoPaint, photostyler and others.
Rice. 18. Working window of the Adobe Photoshop raster editor
The basis of the future drawing can be created in a vector graphics editor, and then exported to raster format. Let's look at the main raster formats used by various programs:
§ BMP(Windows Device Independent Bitmap) - the simplest raster format is a native Windows format; it is supported by all graphics editors running under its control. In BMP, color data is stored only in the model RGB, both indexed colors (up to 256 colors) and full-color images are supported, and in the indexed color mode the simplest RLE (Run Length Encoding) compression is possible. Without compression, the file size is close to the maximum possible. Thanks to the most primitive image recording algorithm, very little system resources are consumed when processing BMP format files, so this format is very often used to store logos, screen savers, icons and other elements of graphic design of programs.
§ PCX(Soft Publisher's Paintbrush) - has approximately the same capabilities as BMP, developed at the dawn of the computer era by Z-Soft specifically for its graphic editor PC PaintBrush under operating system MS-DOS. But images in PCX format can be viewed by most DOS programs, including the internal Norton Commander viewer. Color capabilities: 1, 2, 4, 8 or 24-bit color, only RGB color scheme is supported, and there is no ability to save a monochrome image in grayscale. ROB compression is always applied. Like BMR, this format is largely outdated and is supported by modern graphics programs solely for compatibility with antique software.
§ GIF(Graphics Interchange Format) - is the most popular format on the Internet, proposed by CompuServe back in 1987. Its distinctive feature is the use of the indexed color mode (no more than 256), which limits the scope of the format to images with sharp color transitions. The GIF format is a favorite format of webmasters, who use it to save numerous design elements of their pages. The small size of image files is due to the use of the LZW lossless compression algorithm, making images in this format most convenient for sending over still narrow communication channels global network. In 1989, the format was updated and renamed GIF89A. What distinguishes it from the previous version is the presence of an additional alpha channel to implement the transparency effect (unfortunately, no more than one gradation) and the ability to store several pictures in one file, indicating the display time of each, which is used to create animated GIF files.
§ PNG(Portable Network Graphics) - the PNG format, which is the fruit of the labors of a community of independent programmers, was born as a response to the transition of the most popular GIF format into the category of commercial products. This format, which compresses graphic information without loss of quality using the Deflate algorithm, unlike GIF or TIFF, compresses raster images not only horizontally, but also vertically, which provides a higher compression ratio and supports color photographic images up to and including 48-bit . As a disadvantage of the format, it is often mentioned that it does not allow creating animated videos, although now, with the general transition of almost all animation to Flash technology, this is no longer relevant at all. But the PNG format allows you to create images with 256 levels of transparency due to the use of an additional alpha channel with 256 shades of gray, which certainly makes it stand out from all currently existing formats. Other distinctive features of this format include two-dimensional interlaced scanning (i.e., the image appears gradually not only in rows, but also in columns) and built-in gamma correction, which allows you to save images whose brightness will be unchanged not only on any PC machines , but also on alternative platforms such as Mac, Sun or Silicon Graphics. Since the format was created for the Internet, there is no space in its header for additional parameters such as resolution, so PNG is not well suited for storing images to be printed; PSD or TIFF are better suited for these purposes. But it is good for publishing high-quality raster graphics on the Internet.
§ JPEG(Joint Photographic Experts Group) - the most popular format for storing photographic images, is a generally recognized standard on the Internet. JPEG can only store 24-bit full color images. The format has the same name and is quite a complex compression algorithm based on the peculiarities of human vision (it uses the representation of a block of 8x8 pixels in one color while preserving information about brightness, plus the Huffman method and, depending on the degree of compression, some other tricks). Although JPEG perfectly compresses photographs, this compression is lossy and spoils the quality, however, it can be easily configured for minimal losses, almost imperceptible to the human eye. By the way, you can increase compression and minimize quality loss by first blurring the image (for example, using the blur filter). However, you should not use the JPEG format to store images that are subject to subsequent processing, since each time a document is saved in this format, the process of image quality deterioration is avalanche-like. It would be most advisable to correct the image in some other suitable format, such as TIFF, and only after all work is completed can the final version be saved in JPEG. Thus, you can maintain quite acceptable image quality with a minimum size of the final file. The JPEG format does not support animation or transparent color, and in the vast majority of cases is only suitable for publishing full-color images, such as photographic ones, on the Internet.
§ TIFF(Tag Image File Format) - developed by Aldus for its graphic editor PhotoStyler, which, however, is no longer developing, but the format itself was destined for a much longer life. As a universal format for storing raster images, TIFF is widely used, primarily in publishing systems that require the best quality images. By the way, the ability to record images in TIFF format is one of the hallmarks of the high class of modern digital cameras. The format supports a variety of compression algorithms (including the popular LZW, Deflate or JPEG), image types from bitmap (1-, 2-, 4-, 8-, 24- and 32-bit images) and indexed colors to LAB, CMYK and RGB (except duplex and multichannel documents). In addition, there are two varieties of the format, respectively for IBM PC and Macintosh, due to the different order of recording numbers implemented on these platforms. This format supports such purely professional features as clipping paths, alpha channels, the ability to save multiple copies of an image at different resolutions, and even include layers in the file. Due to its compatibility with most professional image processing software, the TIFF format is very convenient when transferring images between computers various types(for example, from PC to Mac and vice versa).
§ PSD(Adobe Photoshop) - is a standard format of the Adobe Photoshop package and differs from most conventional raster formats in the ability to store layers. It contains many additional variables (not inferior to TIFF in their number) and compresses images using the RLE Packbits lossless compression algorithm, sometimes even stronger than PNG (only in cases where file sizes are measured not in kilobytes, but in tens or even hundreds of megabytes). The format supports color depths up to 16 bits per channel (48-bit color and 16-bit black and white), as well as alpha channels, layers, outlines, transparency, vector lettering, etc. Perfect for transfer or storage images containing specific elements unique to Adobe Photoshop. PSD files are easily readable by most popular viewers, but do not forget that by opening these files in some third-party graphic editors, even those that declare support for the PSD format, you can lose a significant part of their specific capabilities.
1. Vector graphics
The main element in vector graphics is line. A line is an elementary vector graphics object. All objects in the image consist of lines. For example, a quadrilateral object can be thought of as four connected lines, and a cube object can be thought of as twelve connected lines or as six connected quadrilaterals. Because of this approach, vector graphics are often called object-oriented graphics.
Like all objects, lines have the following properties: form, thickness, color, type. Closed lines have the property filling color, texture, map. The simplest line, if it is not closed, has two vertices, which are called nodes. Nodes also have properties that affect how the vertex of a line looks and how two lines fit together.
Since all images are displayed on the screen in the form of points, before outputting vector images, the program calculates the coordinates of screen points in the object image, which is why vector graphics are sometimes called calculated.
Adobe's Photoshop package occupies a special place in the broad class of programs for processing raster graphics. 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:
− Palette Brushes 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.
− Palette Options serves 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.
− Palette Info 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.
− Palette Navigator 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.
− Palette Synthesis 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 chosen from the set. The standard package of the program includes several color sets, mainly from Pantone.
− Layers Palette serves to control the display of all layers of the image, starting from the top one. It is possible to determine the parameters of layers, change their order, and operate on layers using different methods.
− Channels Palette used to select, create, duplicate and delete channels, determine their parameters, change the order, convert channels into independent objects and generate combined images from several channels.
− Palette Contours contains a list of all created contours. When you convert a path to a selection, it is used to form a clipping path.
− Palette Operations allows you to create macro commands - a specified sequence of operations with an image. Macros can be recorded, executed, edited, deleted, or saved as files.
A special group of image processing software is represented by Filters. 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.