meljun cortes multimedia lecture chapter4 graphics

8/10/2019 MELJUN CORTES Multimedia Lecture Chapter4 Graphics

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Chapter 4

Graphics

MELJUN CORTES


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Chapter Objectives

Explain why graphic images are vital to multimediaapplications

List the items that should be logged in reference tographic imagesDescribe the role and responsibilities of the graphicdesigner

Describe the different technologies that can be usedto capture and acquire digital imagesDefine the different types of images

Harcourt, Inc. items and derived items copyright 2002 by Harcourt, Inc .


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Chapter Objectives

Explain how color resolution and image resolutionaffect image quality

Define compression and compare lossy and losslesscompressionExplain the difference between bitmapped andvector-based graphics

Describe several features of paint, draw, 3D, andimage editing programsList and describe the different Web graphic fileformats



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Introduction

Society is very visual

Picture really can be worth a thousand words



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Introduction

Choosing an ImagePrepare list and descriptionTrack vital information in an image log

DescriptionSourceRights negotiatedAmount paid



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The Graphic Designer

Create and optimize images for theWebPart of multimedia teamFreelance

Portfolio



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Digitizing Images

Converting them to 0s and 1s



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Scanners

Page/FlatbedPage-fed

OCR SoftwareSlide



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Scanning Hints

Set resolution to 72 ppiWork from an originalDo not increase resolution after ithas been lowered



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Digital Cameras

Require no film

Store images in memory (flash RAM)Connect directly to the computerRange in price, quality and features



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Snapping Photographs

Take lots of photosShoot from a variety of anglesShoot people in indirect lightShoot in the morning/evening when

light is filteredTry shooting objects both indoorsand outdoors



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Digital Video Cameras

Capture both still and moving imagesRange in price, quality, and features



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Photo CD

Service bureauHigh qualityInexpensiveConvenient

Near-permanent storage



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Stock Photography

Commercial Image providers/Stockphotography housesTips

File should be Web readyGraphic should be size and resolutionappropriate to Web page



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Clip Art

Available with software, on CD andWeb Must be appropriate and high qualityCan look amateurish

Public domain v.copyright Read licensing agreements carefully



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Original Artwork

Draw, paint, image editing software learning curveDont have to worry about copyright orlicensing agreementsDigitizing or Graphics tablet stylusSpreadsheet software charts/graphsMapping software vector-based



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Types of Images

Line art flat colorsContinuous tone photographsGrayscale 256 levels of grayTwo-dimensional

Three-dimensionalHypergraphicsImage Maps



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Image Quality

Many factors impact image qualitySome are dependent on equipment

No control over differences in gammasettings, dot pitch, and display settingssuch as monitor resolution and color

Web designers constantly weigh imagequality v. file size/download time



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Color Resolution

Also calledBit or pixel resolutionColor, bit, or pixel depth

Measures the number of bits ofstored information per pixel or howmany colors each pixel may containColor resolution chart



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Color Resolution

Greater color resolutionHigher quality imageLarger file size Different color palette



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Web-safe color palette

Also calledBrowser-safe color palette and 6 x 6 x 6palette

216 safe colors Dithering and Banding



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Image Resolution

Amount of information stored foreach imageMeasured in pixels per inch (ppi)Computer monitors display 72 ppiSetting Web graphics higher than 72ppi makes them larger in file size andon screen



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Optimizing Images

Crop to smallest areaApply image size for final Web pageReduce resolution to 72 ppiReduce colors to minimum withoutsacrificing quality



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Image Compression

Compression algorithm used tocreate smaller file sizesTwo types

LosslessLossy



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Graphics Software

Include drawing, painting and imageediting programsTool palette



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Paint Programs

Bitmapped images pixel-basedEditable pixel by pixelEnlarging may result in jaggiesMicrosoft Paint

Create and edit geometric figuresAdd color and patternsCut and pasteRotate and stretch



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Draw Programs

Vector graphics mathematical modelsResize without losing image qualitySmooth, precise, versatileGenerally require less memory

May take longer to refresh



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Draw Programs

Adobe Illustrator , Macromedia Freehand,CorelDraw

Fully editable shapesBzier curvesGradient fillsBlending/morphing

GroupingRasterizingConverting a vector-based graphic to pixelsImproves refresh rate



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3D Modeling Programs

Also called rendering programsTextures applied to wire-frame modelRendering

Converting a three-dimensional image toa two-dimensional image



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3D Modeling Programs

Bryce, Canoma, Carrara,Poser, LightWave,

SoftImageModelingArranging and deformingShading

Setting lights and cameras Rendering



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Image Editing Programs

Manipulate digitized imagesAdobe PhotoShop

CroppingBrightness, Contrast, Color CorrectionFiltersLayersFile Format Conversion



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Enhancement Programs

Plug-insAdd-on features

Programs specifically designed forworking with Web graphics andanimation

Macromedia FireworksAdobe Image Ready



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Web Graphic File Formats

Graphics Interchange Format (GIF)Joint Photographic Experts Group(JPEG)Portable Network Graphics (PNG)



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GIF

Developed by CompuServeSupports 256 colors (8-bits)Uses lossless compressionSupports interlacing (GIF 87a)

Supports transparency (GIF 89a)AnimationBest for solid color images/diagrams



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JPEG

Supports millions of colorsUses lossy compressionProgressive jpegs support interlacingRectangular do not supporttransparencyBest for photographs/continuous toneimages



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PNG

Supports various color depths (8-bit to 32-bit)

Uses lossless compressionGenerally creates smaller files than GIFSupports variable transparency

Supports interlacing fasterCapacity for gamma correctionNot supported by all browsers w/o plug-in

Harcourt Inc items and derived items copyright 2002 by Harcourt Inc

meljun cortes multimedia lecture chapter4 graphics

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