Graphic• A digital representation of non-text

information– Drawing– Chart– Photograph

• Also called graphical image• There is no movement or animation in a

graphic

Graphic (cont’d)• Graphics are used to illustrate certain concepts more

clearly than text can (Saturn’s rings)• Graphics play an important role in teaching since

many people are visual learners – think about car icons or road signs

• Graphics serve as navigation aids in many software packages (think about buttons, even in Windows or on the Mac)

Graphic (cont’d)• Sources of graphics:– Clip art packages– Scanners or digitizers– Digital cameras– Stock photograph agencies– Draw/paint programs

Animation• A graphic which has the illusion of motion by

displaying a series of still graphics• Examples– Office Assistant– Demonstrations of how something works (engine)– Simulations (hospital ward)

• Used for better illustration that a graphic• Sources:– Web or CD-ROM for canned animations– Web development packages (animated GIFs)– Commercial animation or rendering software

Audio• Music, speech or any other sound.• Sources:– Microphone– CD-ROM, DVD-ROM– Sound card input– Radio card– MIDI– Can also purchase canned audio clips– Web– Music composition suites

Audio (cont’d)• Useful for concepts that cannot be conveyed

with sound – vibration of a bearing• Can supplement text and graphics and

enhance learning

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Graphics

• Desktop publishing• Image editors• Illustration programs• Image galleries • Graphic suites

4-9

Desktop Publishing

• Programs that allow you to create publications– Mix text and graphics– Professional quality

• Popular programs– Adobe Page Maker– Microsoft Publisher– QuarkXPress

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Image Editors

• Programs for creating and editing bitmap images – Bitmap images use dots or pixels to represent an

image– Bitmap images are also called raster images

• Popular programs– Microsoft Paint– Adobe Photoshop– Corel PhotoPaint

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Illustration Programs

• Programs used to create and edit vector images• Drawing programs• Vector images use geometric shapes or objects • Popular programs– Adobe Illustrator– CorelDraw– Macromedia FreeHand– Micrografx Designer

4-12

Image Galleries

• Libraries of electronic images• Used for a variety of applications • Two basic types– Stock photographs – Clip art

4-13

Image Galleries

Organization Site

Art Today www.arttoday.com

Broderbund www.broderbund.com

Design Gallery Live www.dgl.microsoft.com

GifArt www.gifart.com

Graphics Maps www.graphicsmap.com

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Graphic Suites

• Bundled graphic programs• Can buy a larger variety of graphics programs

at a lower cost• Popular suites– CorelDraw Graphics Suite– Corel's Graphic Pack– Micrografx's ABC Graphic Suite

Raster vs Vector

In the world of computer graphics, there are two types of images - raster and vector. Some programs that create raster images (also known as pixel or paint images) are Photoshop or Paintbrush. Some programs that create vector art (also known as object-oriented art) are Illustrator and FreeHand. Other programs, such as CorelDRAW, have tools to create both raster and vector images.

Raster Images

Raster images are made up of a whole lot of tiny dots, called pixels. To illustrate this concept, we will use a sheet of graph paper. Each square on the sheet represents one pixel. Let's start simple and create a black and white circle that is 20 pixels in diameter.The number of pixels determines the resolution of your file. The computer stores this file by recording the exact placement and colour of each pixel. The computer has no idea that it is a circle, only that it is a collection of little dots.

Each pixel has a coordinate, and the contents of that pixel are recorded and saved in a file.

In the previous example, we see each individual pixel, and the circle is very blocky. By adding more pixels, thereby increasing the resolution, we can make that same circle appear smoother because the pixels are much smaller. Of course, the higher your resolution is, the larger your file size will be because the computer has many more pixels to keep track of.Where the problem arises is when you try enlarging a raster image. Because the resolution is set, when you scale the art, in reality, you are just enlarging the pixels, which results in a jaggy (or pixelated) image.

Vector Images

Vector art is different in that instead of creating individual pixels, you create objects, such as rectangles and circles. By noting the mathematical coordinates of these shapes, a vector program can store files in a fraction of the space as raster images, and more importantly, be able to scale images to virtually any size without any loss in detail.

Unlike raster images, the vector circle appears smooth at 100% (left) and just as smooth when enlarged 800% (right).

These two graphics shows the differences between an enlarged vector graphic on the left (notice the smooth edges) and an enlarged bitmap graphic on the right (note the jagged edges). Many companies have their logos created as vectors to avoid problems with scaling: A vector graphic logo maintains its high quality appearance at any size.