Computer Concepts 5th Edition Parsons/Oja Page 330 CHAPTER 7 Bitmap Graphics Section A PARSONS/OJA...

Computer Concepts 5th EditionParsons/Oja

Page 330

CHAPTER

7

Bitmap GraphicsSection A

PARSONS/OJA

Digital Media


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Section AChapter

7Digital Media

The Big Picture…

Bitmap graphics Converts image to “off and on” Pixels

• Number• Edit

Changing size of image. Become pixelated.• Large files

Compressing bitmap files JPEG, GIF, PNG Images can be viewed by web browser


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The Big Picture…

Vector graphic – consists of set of instructions for re-creating a picture Resize better Less storage space Easier to edit Not as realistic

3-D Graphic Design, cartoon Requires computing power


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7Digital Media

The Big Picture…

Digital camera Number of pixels Type of storage Method of transferring images to computer


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7Digital Media

The Big Picture…

Desktop video Series of images

• Compression Transfer to computer Editing

• Decent computing capabilities Conversion from analog


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7Digital Media

The Big Picture…

Digital sound MP3: method of compression MIDI: used to store music data Speech synthesis: used to produce “spoken

words” Voice recognition software: problems


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7Bitmap Graphics

Bitmap Basics: What is a bitmap graphic?

Bitmap graphic – “raster graphic”, consists of a grid of dots, and the color of each dot is stored as a binary number


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7Bitmap Graphics

Where can I find bitmap graphics?

Often used to create realistic images Cartoons in video games 3-D graphics software Digital cameras E-mail photos


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7Bitmap Graphics

How do I create bitmap images?

Paint software – graphics software for creating bitmap graphics Adobe Photoshop Jasc Paint Shop Pro Microsoft Paint


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Scanners and Cameras: How do I convert a printed image into a bitmap?

Scanner – converts printed pages and images into a bitmap graphic Divides image into fine grid of cells, and

assigns a digital value for the color of each cell Values are transferred to your computer’s disk

and stored as a bitmap


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When should I use a digital camera rather than a scanner?

Digital camera – digitizes real objects Takes photo in

digital format, which you can then transfer directly to your computer


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How does a digital camera store images?

The type of memory module used by a digital camera depends on the brand and model

Flash memory – popular technology for digital camera memory modules Holds data without consuming power


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How does a digital camera store images?


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How do I get the images out of the camera?

Direct cable transfer – Fire Wire ports are used to transfer data

Infrared port – cameras “beam” the data to computer’s infrared port

Memory card readers – small device connected to computer and designed to read flash cards

Floppy disk adapters – adapter shaped like a floppy with slot for a flash memory module


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How do I get the images out of the camera?


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Modifying Bitmap Graphics: What characteristics of a bitmap can I modify?

You can use graphics software to modify or edit bitmap graphics by changing individual pixels Retouch Repair Remove red eye or erase “rabbit ears”

Bitmap graphics require large amounts of storage, and take long time to load May not fit on a floppy disk


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Image Resolution: How does resolution pertain to bitmap graphics?

Resolution – dimensions of the grid that forms a bitmap graphic Number of horizontal and vertical pixels that it

contains 150 x 100 – 150 pixels across and 100 pixels

high


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How does resolution relate to image quality?

High-resolution graphics contain more data than low-resolution Better printouts

Megapixels – total number of pixels in a graphic


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How does resolution relate to the file size of a graphic?

Each pixel is stored as one or more bits More pixels means larger file size


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7Bitmap Graphics

How does resolution relate to the physical size of an image?

Bitmap has no fixed physical size Size depends on density Graphic retains same resolution no matter

how much you stretch or shrink the graphics physical size


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7Bitmap Graphics

How does resolution relate to the physical size of an image?


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7Bitmap Graphics

How do I specify the size of a printed image?

Most graphics software lets you specify the size at which image is printed without changing the resolution of the bitmap graphic Get better printout if an image meets or

exceeds the printers dpi (dots per inch)


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How does a bitmap’s resolution relate to what I see on the screen?

Typically, one pixel corresponds to one pixel on the screen

If image is larger than screen, you will have to scroll


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7Bitmap Graphics

Can I change a graphic’s file size?

Cropping – process of selecting part of an image Resolution dependent – quality of the image

depends on its resolution Can reduce image quality

If you attempt to enlarge a bitmap, computer must add pixels

Pixel interpolation – creates new pixels by averages the colors of nearby pixels

Pixelated – undesirable bitmappy appearance


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Can I change a graphic’s file size?


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Color Depth and Palettes: What is color depth?

Color depth – is the number of colors that are available for use in an image Larger number, better quality and larger file

size


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7Bitmap Graphics

How does color depth relate to file size?

True color bitmap (24-bit bitmap) – 16.7 million colors Each pixel requires 3 bytes of storage Color based on intensity levels or red, green,

blue 8-bits red, 8-bits green, 8-bits blue (24-bits)

32-bit bitmap – 16.7 million colors plus special effects


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How can I reduce color depth?

Reducing color depth can reduce size of file To reduce color depth, manipulate color palette Color palette – digital version of artist’s palette

that holds the selection of colors for use 256 colors – eight bits per pixel (1/3 size

required for true color bitmap)


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How does a color palette work?


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How do I select a color palette?

Use color palette or color picker tool Grayscale palette – displays an image using

shades of gray (usually 256 shades of gray) System palette – selection of colors used by the

operating system Windows has 20 permanent colors and 236

that can be changed Web palette – standard set of colors used by the

Internet Web browsers


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So what should I do about color depth?

Bitmap graphics that you wish to print should remain in True Color format

Those sent in e-mail or posted on Web site should be reduced to 256-color palette


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Bitmap Graphics Formats: Are there different kinds of bitmap graphics?

BMP – native bitmap graphic file format of Microsoft Windows OS

PCX – one of original personal computer bitmap graphics file formats (8-bit – 256 color)

TIFF (Tag Image File Format) – highly flexible and platform-independent graphics file format Supports True Color Used by scanners and digital cameras


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Are there different kinds of bitmap graphics?

JPEG – graphics format with built-in compression You control level of compression Uses True Color

GIF – limited to 256 colors PNG – 48-bit True Color, compresses without

losing data Public domain format


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How do I know which graphics format to use?

Selecting the best graphics file format to use depends on what you intend to do with the image Scanned and digital images – could be stored

as JPEG or TIFF format Images for web pages – GIF or JPEG format Designing Windows controls – BMP format


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7Vector and 3-D Graphics

Vector Graphics Basics: What is a vector graphic?

Vector graphic – consists of set of instructions for re-creating a picture

Instead of storing the color value for each pixel, a vector graphic file contains the instructions that the computer needs to create the shape, size, position, and color for each object in an image


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What is a vector graphic?


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How can I identify vector graphics?

Flat, cartoon-like quality Filename extension

.wmf .dxt .mgx .eps .pict .cgm


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What are the advantages and disadvantages of vector graphics?


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Vectors resize better than bitmaps Vector images usually require less storage space

than bitmaps It is easier to edit an object in a vector graphic

than an object in bitmap graphic Vector graphics tend not to produce images that

are as realistic as bitmap images


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What tools do I need to create vector graphics?

Drawing software – vector graphics software Helps you easily edit individual objects by

changing their sizes, shapes, positions or colors


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Gradient – smooth blending of shades from one color to another, or from light to dark

Metafiles – graphics that contain both bitmap and vector data Apply bitmap texture to vector graphic


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Vector-to-Bitmap Conversion: Is it possible to convert a vector graphic into a bitmap?

Rasterization – works by superimposing a grid over a vector image, and determining the color for each pixel

Once converted, the resulting graphic no longer has the qualities of a vector graphic


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How about converting a bitmap graphic into a vector?

Tracing software – locates the edges of objects in a bitmap image and converts the resulting shapes into vector graphics objects


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Vector Graphics on the Web: Do vector graphics work on the Web?

Browsers support a limited number of graphics formats – Gif and Jpeg

Support for vector graphics has been slow, but plug-ins and players are currently available


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Which vector graphics formats can be used on the Web?

SVG (Scalable Vector Graphics) – designed for the Web Automatically resized when displayed on

different screens Uses <EMBED> tag

Flash graphics – can be static or animated and require less space than SVG graphics, but require a browser plug-in to be viewed


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What are the advantages of using vector graphics on the Web?

Vector graphics appear with same consistent quality on all computer screens

Any text contained in a vector image is stored as actual text, not just a series of colored dots

Vector graphics on the Web have compact file sizes


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How do vector graphics relate to 3-D graphics?


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What do I need to work with 3-D graphics?

3-D graphics software AutoCad, Caligari truSpace

High-end workstations 500 MHz Pentium or Macintosh G3 or better High-resolution monitor Graphics card with lots of memory


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What do I need to work with 3-D graphics?

Click to start


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Is it possible to animate 3-D graphics?

3-D graphics can be animated to produce special effects for movies, or create interactive, animated characters and environments for 3-D computer games Pixar Animation Studios DreamWorks

Special effects can be created and incorporated into final footage

3-D computer game animation happens in “real-time”


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7Desktop Video

Desktop Video Basics: What is desktop video?

Desktop video – videos that are constructed and played using a personal computer Stored on hard disks, CDs, DVDs, videotapes,

or the Web Not quite like standard of DVD movies, but

suitable for variety of personal and professional uses


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7Desktop Video

How do computers store video data?

Video is composed of a series of frames Each frame is essentially a still picture (can be

stored as bitmap graphic) Frame rate – number of frames per second

Feature films – 24 fps (frames per second) Desktop video – 15 fps


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7Desktop Video

How do I equip my computer to play desktop videos?

Most computers equipped for viewing videos; however, video playback quality can vary

Depends on Microprocessor RAM capacity Capabilities of graphic card

For web, Internet connection speed is also issue


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7Desktop Video

How do I equip my computer to play desktop videos?

For Internet also need Player –

Quicktime, Windows MediaPlayer

Click to start


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7Desktop Video

What file formats are most popular for desktop videos?

Several file formats are popular for desktop videos AVI QuickTime MPEG RealMedia ASF


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7Desktop Video

Can I create my own desktop videos?

The basic process consists of following steps Shoot the video footage Transfer the footage to your computer’s hard

disk Edit the video and soundtrack Output the video in its final format by selecting

frame rate, window size, file format, and compression levels


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7Desktop Video

Video Cameras: Is it necessary to use a digital camera to capture footage for desktop video?

You can use analog or digital video camera to shoot footage

Digital video camera – stores footage as a series of bits

Analog video camera – normal video camera Video signal stored as continuous track of

magnetic patterns Must be digitized

Videoconferencing cameras – attach to computer


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7Desktop Video

Is it necessary to use a digital camera to capture footage for desktop video?


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7Desktop Video

What are the advantages of a digital video camera?

Captures video data in digital format which can then be directly transferred to a computer for editing

Produce higher quality video than analog or videoconferencing cameras

Images tend to be sharper and more colorful Higher quality of original video, the better the final

video will look


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7Desktop Video

What are the advantages of a digital video camera?


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7Desktop Video

Does desktop video require special filming techniques?

When processed and stored, some of image data is eliminated to reduce the video file to a manageable size

To produce good quality video Use a tripod to maintain a steady image Move the camera slowly Zoom in and out slowly Direct your subjects to move slowly Position your shot well Ask the subjects of your video to wear solid

colored clothing


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7Desktop Video

Video Transfer and Storage: Why is it necessary to transfer footage from my camera to my computer?

In order to digitally edit, process, and store a desktop video, you must transfer the video footage from your camera to your computer


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7Desktop Video

How do I transfer video footage to my computer?

Basic method for transferring video footage is to send the data over a cable that connects your camera to your computer

Equipment depends on your camera and your computer

Video capture device – converts analog camera signal into digital data


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Video capture software – allows you to start and stop the transfer, and select the display size, frame rate, filename, and file format for your video footage


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How does video footage become a desktop video?

After editing, video editing software combines data from all of the video and audio files that you selected into a single file as a desktop video Select file format, QuickTime or AVI

A full-screen True Color image at 1,024x768 resolution requires 2,359,296 bytes; with 24 fps, requires 56,623,104 bytes

10 minutes requires almost 34 GB of storage space

To shrink, decrease size of window, number of frames, and select a compression technique


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7Desktop Video

How does video footage become a desktop video?

To reduce size Decrease the size of the video window Reduce the frame rate Compress the video data

• Codec (compressor/decompressor) – software that compresses a file when a desktop video is created and decompresses the file when video is played

MPEG, Indeo, Cinepak, DivX, Video 1


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7Desktop Video

Which compression technique should I use?

The ultimate goal is to store a high-quality video image in a small file Difficult to predict the result of compression Codec used to compress must be used to

decompress the video when it is played Missing codecs account for high proportion of

desktop video glitches


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Which compression technique should I use?


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Web-based Video: How do Web-based videos work?

Streaming video – sends small segment of the video to your computer and begins to play it Web server sends next part of the file to your

computer, and so on, until the video ends


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7Desktop Video

How does Internet connection speed affect Web videos?

Dial-up connections are slow Typical 56 Kbps connection reach speeds of only

44 Kbps• Video to play At 15 fps, with 256 colors, 357 bytes

per frame; playing in a window of 15 by 11 pixels (1/6 of an inch wide)

High-speed Internet connections provide much more bandwidth for streaming video

Most Web sites provide one video file that’s optimized for dial-up and one optimized for high-speed (DSL, cable, and ISDN connections)


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7Digital Sound

Waveform Audio: What is waveform audio?

Waveform audio is a digital representation of sound. Music, voice,

and sound effects can all be recorded as waveforms


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7Digital Sound

Does sampling rate affect sound quality?

Sampling rate – refers to number of times per second that a sound is measured during the recording process Expressed in hertz (Hz)

Audio CDs have sampling rate of 44.1 KHz Stereo effects, requires 32 bits of storage space

for each sample Floppy, stores only eight seconds of music 45 minutes of music – 475 MB To conserve space, reduce sampling rate


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7Digital Sound

Does sampling rate affect sound quality?


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7Digital Sound

How does a computer produce waveform audio?

Sound card – contains a variety of input and output jacks, plus audio-processing circuitry Plugs into a PCI expansion slot inside the

system unit


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7Digital Sound

How does a computer produce waveform audio?

Digital signal processor – performs three important tasks Transforms digital bits into analog waves Transforms analog waves into digital bits Handles compression and decompression, if

necessary


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7Digital Sound

How can I recognize a waveform audio file?

Recognize a waveform audio file by its extension Wave (.wav) – created by Windows Audio Interchange Format (.aif) – created by

Apple RealAudio (.ra) – proprietary format created

by RealNetworks MP3 (.mp3) – MPEG format, popularized by

Napster


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7Digital Sound

How can I recognize a waveform audio file?


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What type of software is required to record and play waveform audio files?

Audio software comes in many flavors To play, you must use an audio player

Microsoft Media Player To record, you may need another software

component Microsoft Sound Recorder software

Software may be part of your operating system or purchased separately


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7Digital Sound

What’s the story with MP3?

MP3 is a compressed waveform audio format that stores digitized music, vocals, and narration in such a way that the sound quality is good, but file size remains relatively small

CD ripper – grabs tracks from audio CD MP3 encoder – converts Wave file into MP3

format MP3 files can be stored anywhere or relocated to

a portable MP3 player


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7Digital Sound

What’s the story with MP3?


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7Digital Sound

MIDI Music: What is MIDI music?

Synthesized sound – artificially created sound MIDI or synthesized speech

MIDI (Musical Instrument Digital Interface) – specifies standard way to store music data

MIDI sequence – encoded music stored as .mid, .cmf, or .rol

Most sound cards are equipped to capture data from a MIDI instrument

Wavetable – set of pre-recorded musical instrument sounds


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What is MIDI music?


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When would I use MIDI music?

MIDI is a good choice for adding background music to multimedia projects and Web pages <EMBED SRC = “sousa.mid”> Embed tags are placed within an HTML

document MIDI software can be used to compose your own

tunes or get permission to use MIDI file that you find on the Web


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Speech Recognition and Synthesis: What’s the difference between speech synthesis and speech recognition?

Speech synthesis – process by which machines produce sound that resembles spoken words

Speech recognition (or “voice recognition”) – ability of machine to “understand” spoken words


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7Digital Sound

How does speech synthesis work?

Phonemes – basic sound units strung together by speech synthesizers

Text-to-speech software – generates sounds that are played through your computer’s standard sound card

Speech synthesis is a key technology in wireless communication


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How does speech recognition work?

Speech recognition software – analyzes the sounds of your voice and converts them to phonemes

Next, the software analyzes the content of your speech; it compares the phonemes to the words in a digital dictionary

Speech recognition software can be integrated with word processing software so that you can enter text by speaking into a microphone

Computer Concepts 5th Edition Parsons/Oja Page 330 CHAPTER 7 Bitmap Graphics Section A PARSONS/OJA...

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Transcript of Computer Concepts 5th Edition Parsons/Oja Page 330 CHAPTER 7 Bitmap Graphics Section A PARSONS/OJA...