XP Practical PC, 3e Chapter 13 1 Working with Graphics

Practical PC, 3eChapter 13

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XP

Chapter 13

Working with Graphics


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XPWorking with Graphics

• In this Chapter, you will learn:– What kind of graphics I can work with on the PC

– When to use bitmap graphics

– How to prepare graphics for Web pages

– When to use vector graphics

– How to create 3-D graphics

– How to edit a digital photo

– About Digitizing devices


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XPWhat kind of graphics can I work with on my PC?

• Graphics or images are the pictures used in documents to add interest and visual explanations.

• Using graphics software, you can create, edit and store graphics on your computer.

• You can get graphics from many sources, including downloading from the internet, scanning paper sources, and buying clip art collections.

• There are two basic types of images you may use – bitmaps and vector graphics.


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XPWhat kind of graphics can I work with on my PC?

A Bitmap vs. a vector graphics image


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XPWhen to use bitmap graphics

• In a bitmap graphic, the image is represented by a grid of colored dots.

• Bitmap images can be used to represent photo type images.

• Bitmap image file types include BMP, TIFF, GIF and JPEG.

• Paint software such as Adobe Photoshop and Corel PhotoPaint will create and edit bitmaps.


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• Bitmap quality depends on resolution and color depth.

• Higher resolution images show detail clearly.• The number of color variations in an image is

called color depth.• True color , a 24-bit color depth produces 16.7

million colors but takes 3 times the storage space of a 256-color image.


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The Windows Paint program

You can change to color of an area with the fill tool

The toolbar offers many tools for drawing and editing images

A square on the grid is one dot in the image

This window shows the actual image


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XPPreparing graphics for Web Pages

• Web page graphics need to load as quickly as possible and still look good.

• Web graphics should be less than 20KB.• Graphic sizes can be reduced by:

– Resizing or scaling the graphic or using a thumbnail with a link to a bigger graphic

– using a compressed format such as GIF or JPEG

– reducing color depth to 256-color or dithered 16-color


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XPPreparing graphics for Web Pages

256 color, dithered 16-color, and non-dithered 16 color


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XPWhen to use Vector Graphics

• In a Vector graphic, the image is represented by points, lines, arcs and other geometric shapes.

• A shape consists of line segments (vectors) with different widths and fill colors.

• Vector graphics are used for diagrams, line drawings and computer-aided design (CAD).


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• The advantages of a vector graphic include:– They are usually small

– They can change size with no loss of quality

– Each shape is independent and can be modified individually

• Vector graphics file types include EPS and WMF.• Vector graphics can be created/edited by packages

such as Adobe Illustrator and Corel Draw.


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Using Micrografx software to add vectors to an image


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XPCreating 3-D graphics

• 3-D graphics appear to be three dimensional and also allow you to view the object from all angles.

• When creating a 3-D object, you produce a line drawing called wireframe of each surface of the object.

• Then you apply surface information to each surface (called rendering). This is similar to draping a covering over a frame.


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• You also will specify a light source and the software will create bright spots and shadows.

• This process is called ray tracing.• The rendering process can require extensive

computer power and time.• The finished image are very well defined with

unflawed surfaces.


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The rendering process in creating a 3-D image


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XPHardware – Digitizing devices

• An image that you can work with on your PC must be in digital format.

• A digitized image has been converted to a series of 0s and 1s.

• Images can be digitized by devices such as graphics tablets, scanners or digital cameras.


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• A graphics tablet is like a drawing pad.• Using a pen-shaped stylus you can draw on the

pad.• The images drawn on the tablet are then converted

to bitmap graphs.• The tablet is sensitive to where you touch the

stylus and how much pressure is applied.


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A graphics tablet


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• Scanners can digitize text, images, and bar codes.• Flatbed scanners resemble small copiers.• Scanning software allows you to adjust the size,

resolution and other characteristics of the scanned image.

• OCR software allows you to scan and interpret text so that it can be read into word processing software.


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Scanning with a flatbed scanner


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• Digital cameras take photos much like a regular camera, but store them as bitmap images instead of exposing the image on film.

• Digital cameras store images in a variety of ways, such as on a PCMCIA memory card, a floppy disk or in flash memory.

• Flash memory holds data without a constant supply of power and then transfers the pictures to the PC over a cable.


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A digital camera


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XPMaking your own CDs

Editing digital photos

Remove Ceiling light

Get rid of red eye

Fix five o’clock shadow

Sharpen edges


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XPWhat do you think?

Shoes, UFOs, and Forrest Gump

1. In your opinion, should photos and videotapes be allowed as evidence in civil and criminal trials?

2. Do you think that it would be possible for someone to use doctored photos and videotapes to convince people that a fake event actually took place?

3. Do you have a set of criteria for judging the authenticity of newspaper and TC images?


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XPChapter Summary

• You should now be able to:– Understand the differences between bitmaps and vector

graphics

– Know when to use each format

– What to do for Web page graphics

– How to create 3-D graphics

– How to edit a digital photo

– Understand the basic types and uses of Digitizing devices

Documents

XP Practical PC, 3e Chapter 13 1 Working with Graphics