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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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

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

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.

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.

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

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

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

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.

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.

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.

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

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.

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.

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

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.

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.

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.

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.