Chapter 14 Working with Graphics

1. Chapter 14Working with Graphics

2. Getting Started • In this Chapter, you will learn: • About different graphics you can work with on your PC • When to use bitmap graphics • Which format to use • When to use vector graphics • How to create 3-D graphics • About Hardware: Digitizing devices Practical PC 5th Edition Chapter 14

3. What kinds of graphics can I work with on my PC? • Pictures that you can create, modify, download, and transmit using your PC are referred to as graphics or images • You can obtain ready-made images • Clip art and stock photo collections • Pictures scanned from books or magazines • You can use photos from your own collection or your digital camera • You will typically work with two types of graphics: vector and bitmap Practical PC 5th Edition Chapter 14

4. What kinds of graphics can I work with on my PC? Practical PC 5th Edition Chapter 14

5. When should I use bitmap graphics? • Bitmap graphics, sometimes called raster graphics, represent an image as a grid of colored dots • Photograph-like images used for photos and Web page images • Stored as BMP, TIFF, GIF, PNG and JPEG • Manipulate the image using paint software • Quality depends on resolution and color depth • Resolution is the width and height of the grid that holds the dots and each dot is assigned a color code • Color depth is the number of bits required to store the color number. The more colors, the more storage space needed • 1-bit color depth produces a black and white image • 8 bit color depth produces 256 colors • 24-bit color depth produces 16.7 million colors, sometimes referred to as true color Practical PC 5th Edition Chapter 14

6. How do I know what format to use? • File format depends on how you plan to use it • For printed publications, use a format that retains a high resolution and 24-bit color depth • For the Web or e-mail attachments, you can use more compact formats • To reduce file size • Shrink the physical dimensions of the image • Use compression techniques • Reduce the color depth • Rules of thumb • JPEG format offers the best quality in the smallest file size • For diagrams, logos, screenshots, and images containing text, use PNG format • GIF works best for logos and images that contain solid blocks of color or a limited range of colors Practical PC 5th Edition Chapter 14

7. When should I use vector graphics? • Vector graphics consist of a set of geometrical shapes • Each shape is defined as a series of line segments called vectors • Vector graphics are ideal for diagrams, line drawings, and computer-aided design (CAD) • Vector graphics resemble line drawings more than photographs • File size tends to be small since shapes can be stored efficiently • Graphics can shrink or expand with no loss of quality • You can modify each shape in a vector graphic independently • Vector graphics are often saved as EPS, WMF, or CAD formats • Drawing software provides tools to create and manipulate vector graphics Practical PC 5th Edition Chapter 14

8. How do I create 3-D graphics? • 3-D graphics contain objects that appear three-dimensional • 3-D objects have the data necessary to display, rotate, and view from any angle • 3-D objects are composed of vectors and are created using same drawing and CAD software that produces 2-D graphics • To create a 3-D object • Produce a wire frame or a line drawing outlining every surface of the object • Render the object by applying texture, transparency, and color to its surface • Your PC automatically determines where to put highlights and shadows using a process called ray tracing • Rendered 3-D graphics have a new-car-brochure look that is sometimes referred to as “super-realistic” Practical PC 5th Edition Chapter 14

9. How do I create 3-D graphics? Creating a 3-D graphic Practical PC 5th Edition Chapter 14

10. Hardware: Digitizing devices • Digitizing converts an image into a series of 1s and 0s that your PC can store and display • Digitizing devices allow you to convert real objects, such as a photo, into a digital format • Graphics tablet • Works like an electronic canvas • Use a pen-shaped stylus to “paint” • Some graphics software does not support the use of a graphics tablet • Connects to USB port • Cost from U.S. $70 to $500+ Practical PC 5th Edition Chapter 14

11. Hardware: Digitizing devices • Scanner • Reads text, images, and bar codes • Typically used for flat objects such as photos • Flatbed scanners are the most popular and resemble small photocopiers • Connects to USB port • Basic unit costs about U.S. $49 • Bundled with software • Scanning software allows you to preview a scan, select a resolution, and initiate a scan from your PC • OCR (optical character recognition) software allows you to convert an image into a text file Practical PC 5th Edition Chapter 14

12. Hardware: Digitizing devices • Digital camera • Takes photos and stores them as bitmap images • Connects to USB port • Can also insert memory card from camera into PC • Transferred images are stored on your PC • Camera prices depend on resolution measured in megapixels. A basic camera costs under U.S. $200 and mid-range cameras cost $200-$1000 • You can open files using paint or photo editing software Practical PC 5th Edition Chapter 14

13. Hardware: Digitizing devices Graphics Tablet Scanner Practical PC 5th Edition Chapter 14

14. Shoes, UFOs, and Forrest Gump? • What do you think? • In your opinion, should photos and videotapes be allowed as evidence in civil and criminal trials? • Do you think that it would be possible for someone to use doctored photos and videotapes to convince people that a fake event took place? • Do you have a set of criteria for judging the authenticity of newspaper and TV images? Practical PC 5th Edition Chapter 14

15. Chapter Summary • You should now know: • About the kinds of graphics you can work with on your PC • Know when to use bitmap graphics • Know what format to use • Know when to use vector graphics • How to create 3-D graphics • About digitizing devices Practical PC 5th Edition Chapter 14