Types of Graphics

1. Types of Graphics • Bitmapped graphics • Simply known as bitmap, is an image formed by a pattern of dots. • Composed of tiny dots of different colors • Each single point in the image is a pixel, short for “picture element”. • The smaller the pixels in the image, the smoother it will look. • The more colors in the image, the brighter and sharper the image will look.

2. Common Bitmapped File Formats • Graphics Interchange Format (GIF) • Joint Photographic Experts Group (JPEG) • Portable Network Graphics (PNG) • Windows Bitmap (BMP) • Some formats are used for images on Web pages. • Others are used for icons and images in the operating system. • The abbreviations are used as the file extensions • Bitmaps are preferred for some types of images. • They often are used for photos or images that require backgrounds.

3. Vector Graphics • A vector graphic is an image that is created using paths or lines. • A vector image tells the computer where a line starts and where it ends. • It allows the computer to figure out how to connect the two points. • Encapsulated PostScript, or EPS, is one of several formats commonly used for vector art. • EPS files contain the information that a printer needs in order to print a graphic correctly. • The information is combined with a small sketch of what the graphic should look like. • The sketch inside an EPS file allows you to preview an image on-screen.

4. Size, Resolution, and Dots Per Inch • Two basic qualities affect how every bitmapped image will appear: • Size • Resolution • Measured in dots per inch, or dpi. • An image that is 1 inch square at 72 dpi will contain a total of 5,184 pixels (72X72). • Generally, the higher the resolution, the sharper the image will look.

5. Size, Resolution and Dots Per Inch continued • Vector graphics are created using lines or paths rather than pixels. • Number of dots per inch is not a concern when changing the size of vector graphics. • If a bitmapped image is enlarged to twice its normal size, it will look fuzzy and jagged. • A vector image can be enlarged to any size and keep its quality.

6. Color Modes for Graphics Programs • Bitmap Mode • refers to a 1-bit, or black-and-white image • Grayscale Mode • the computer can display 256 different shades of gray to represent the colors, shades, and textures in an image. • RGB Mode • Allows clusters of 3 colors (red, green, blue) to have 8 bits of information, resulting in 256 different shades each of the colors red (R), green (G), and blue (B). • CMYK Mode • a combination of four colors in different densities produces other colors. Variations of cyan, magenta, yellow, and black are combined to produce new colors.

7. Input Devices for Graphics • Scanners • device that copies and changes a printed image into a digital format the computer can process and store. • divides the image into boxes and assigns each box a value representing its darkness or color. • Digital cameras • store images digitally instead of on film. • a computer chip in the camera changes light patterns from the captured image into pixels which the camera can store.

8. Graphics Programs • Different programs allow you to create, edit, and view different graphic file types. • Choosing the right program depends on which type of graphic you are working with and what your needs are. • Paint programs • Allows you to create a new bitmapped image. • Provides tools with which you can “paint” each individual dot, or pixel, on the computer screen. • Paint programs also allow you to open a bitmapped image, view it on-screen, and make changes to it.

9. Graphics Programs cont. • Advantages of a paint program • Simple to use • Saves the image as a relatively small file • Disadvantage of a paint program • Inability to enlarge an image without sacrificing its resolution. • Popular paint program • Fractal Design Painter

10. Graphics Programs cont. • Draw Programs • A program that allows you to create and edit vector images. • Store the lines and shapes of an image as mathematical formulas instead of a collection of dots. • Changing the size does not adversely affect its resolution. • Images created with draw programs are called object-oriented graphics or vector graphics. • You can change the size of an image or add color to it.

11. Draw Programs cont. • They create files that are significantly larger than paint programs. • Usually more difficult to use. • Many professional illustrators prefer draw programs because the images are easier to edit than bitmapped images. • Popular Draw programs • Adobe Illustrator • Macromedia Freehand • CorelDRAW • Microsoft Word

12. Image Editors • An advanced paint program is called an image editor. • Designed for editing bitmapped images • Used for adding special effects to photographs • Popular image editors • Adobe Photoshop • Adobe Photodelux

13. Filters in Image Editors • Filter—a preset feature that alters images in a certain way, many are designed to improve photos. • Sharpening Filters • More clearly defines the edges of an image by finding a line of pixels that runs together as one color and is next to other pixels of other colors. • The filter increases the color differences between the line of pixels of one color and those of nearby colors, making the edges more distinct.

14. Filters cont. • Blur Filters—softens the look of an image by making hard edges look blurrier. • can be used to apply this effect to all or part of an image. • Noise Filters—designed to add or remove roughness from an image . • Two types are the despeckle and median filters. • They determine the edges of an image and leave them alone, then they smooth out other areas with less difference in color.

15. Exploring Graphics Programs • Workspace—the blank white area which contains the graphic; sometimes called the drawing area. • Toolbars—contains the icons that link to the program’s tools • Color palettes—display of color options in paint and draw programs

16. Paint Program Tools • Pencil—used for free hand drawing • Used to draw fine details • Only the color or thickness of line can be changed • Brush—works like the Pencil tool, but it makes a broader stroke of color. • Can change the shape of the brush to create different shapes of colors

17. Paint Program tools cont. • Line and shape—allows you to draw a line and use the toolbar to change its color and width. • Various shapes, such as rectangles or ovals, can also be drawn using tools on the toolbar. • Shape tools allow you to create shapes in three different forms: • Outline • Filled with Outline • Filled without Outline

18. Paint Program tools cont. • Eyedropper—allows you to work with a specific color from an image. • Eraser—removes color from an image. • Used by clicking the tool and dragging the eraser across the image.

19. Draw Program Tools • Line and shape tools in draw programs are similar to those in paint programs, but with one important difference. • In a draw program, you can change an image’s lines and shapes without changing nearby ones. • In paint programs, it is hard to change one part of an image without altering other parts that are close to it. • A selection tool allows you to select a portion of an image to be enlarged, moved, or edited.

20. Advanced Draw Program Tools • Align Tool—moves parts of an image and determines how the parts will be placed in relation to one another. • Can be helpful for lining up objects of different sizes • Distribute Tool—moves objects to distribute, or space, them from each other. • Two kinds are fixed amount and within bounds.

21. Adv. Draw Program Tools cont. • Order Tool—changes the position in which objects are stacked and rearranges them to avoid objects being blocked. • Grid Tool—works like a sheet of graph paper by showing squares on the computer screen so you can align objects

22. Interacting with the Program • A variety of different input tools allow you to work easily with a graphics program. • The mouse is used to select part of an image or to activate tools on the toolbar. • A graphics tablet is a piece of hardware used for drawing. • The user moves a stylus, or pointing device, over the drawing surface. • The tablet senses the movement of the stylus and moves the cursor on-screen. • As the cursor moves, it creates on the screen the image that is being drawn on the tablet.

23. Adding Effects to Graphics • Special effects can be used to modify an image. • Flipping an image turns it upside down. • Mirroring the image makes it flip from left to right, as if it were being viewed in a mirror. • Stretching makes the image appear longer in one direction than the other • Skewing tilts the image horizontally or vertically. • Inverting reverses the colors in the graphic.

24. Combining Images • Bringing information, such as a graphic, into a file from another file is called importing. • Once imported the image can then be modified or expanded. • Exporting is when data is formatted so it can be used in another application. • This means that the program you are working in must be able to translate its own language to the language another program understands. • Different processes are used to combine vector images or bitmapped images. • Grouping—for combining vector graphics • Layering—for combining bitmapped graphics

25. Grouping Images • In a vector graphic, different items can be placed together. • Grouping is the process of combining separate images into one image. • Once the images are grouped, they can be moved or resized as a single unit. • To group images, select all of the desired items and then select the Group command. • Ungrouping is the process of separating combined images into individual images. • To ungroup an image, select a grouped image and then select the Ungroup command.

26. Layering Images • Bitmapped graphics use layers, or stacks of information, to create a graphic. • Layering stacks each level of an image on top of another. • Default layer is the background. • You can add or delete layers as needed.

27. Working with Clip Art • Bitmapped Clip Art • Clip art in a bitmapped format can be imported into a paint document and then edited like any other bitmapped graphic. • Vector Clip Art • Can be imported in a draw program and modified. • If the image is complex, it can be ungrouped, then the individual parts can be edited or moved.

28. Converting Graphics • It may be necessary to convert a graphics file into a different type of file, such as from JPEG format to GIF format. • Vector-to-Bitmapped Graphics—based on lines and fills rather than pixels. The lines and fills must be changed to pixels before the image can be edited in a paint program. • Bitmapped-to-Vector-Graphics—based on pixels, not lines, and converting them to vectors requires a special process called tracing. • Tracing requires special software and can be complicated when an image has a lot of color and detail.