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Transcript of Multimedia Elements II Graphics, Digital Video. UIT - Multimedia Production2 Multimedia Elements...
Multimedia Elements II
Graphics, Digital Video
UIT - Multimedia Production2
Multimedia Elements Multimedia elements include:
Text
Graphics Animation
DigitalVideo
DigitalAudio
abvdefghijKlmnopqrstuvwxyz Multimedia
UIT - Multimedia Production3
Multimedia Elements
Graphics Graphics is a digital representation of non-text informatio
n such as a drawing, chart, or photograph. It is also called a digital picture or image, and contains n
o movement or animation 3 fundamental characteristics of color
Hue (色調 ) Related to the wavelength of light
Lightness (亮度 ) Related to the amplitude of light
Saturation (彩度 ) Related to the purity of light
UIT - Multimedia Production4
Multimedia Elements
GraphicsPixel A pixel is the smallest unit of programmable color on a
computer display or in a computer image Every computer graphic is made up of a grid of pixels There are two types of graphics
Bitmap graphics Vector graphics
UIT - Multimedia Production5
Multimedia Elements
GraphicsBitmap Graphics Bitmap is a representation of a graphics image Consists of rows and columns of dots The value of each dot (whether it is filled in or not) is
stored in one or more bits of data Simple monochrome images use one bit to represent
each dot
UIT - Multimedia Production6
Multimedia Elements
GraphicsBitmap Graphics The more bits used to represent a dot, the more colors a
nd shades of gray that can be represented:
1-bit image, 2 color: black or white
8-bit image, 256 colors (28=256)
24-bit image, 16777216 colors (true color)
UIT - Multimedia Production7
Multimedia Elements
GraphicsVector Graphics Vector graphics are based on mathematical formulas
that represent curves and lines Very smooth looking and can easily be resized without
loss of image quality
Bitmap Vector
00000000000000 {(3, 2) (10, 2)}
00111111111100
00000000000000
00000000000000
UIT - Multimedia Production8
Multimedia Elements
GraphicsVector Graphics An example of vector graphic is the clipart in MS PowerP
oint When you enlarge a clipart image, it will not distort
UIT - Multimedia Production9
Multimedia Elements
GraphicsResolution Determines how sharply the image is represented Expressed in dot per inch (dpi), or simply by the number
of rows and columns, such as 640 by 480 Bitmap graphics suffer distortion in image quality when
being scaled up, this does not happen in case of vector graphics
Bitmap graphic Vector graphic
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Multimedia Elements
GraphicsFormats A format is a standard
specifying how the data is arranged
For bitmap graphics BMP GIF JPEG
For vector graphics AI FH WMF
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Multimedia Elements
GraphicsFormats BMP (.bmp)
Microsoft's native graphic file format GIF (Graphic Image Format) (.gif)
Only supports 256 colors; It serves as compressed web graphics. GIF works best when the number of colors within an image is small
JPEG (Joint Photographic Experts Group) (.jpg) Supports millions and allows for graphic compression. Most people use
JPEG for Web graphics that contain a multitude of colors and gradations - like photographic images
AI (Adobe Illustrator) (.ai) For graphics produced by Adobe Illustrator
FH (FreeHand) (.fh) For graphics produced by FreeHand
WMF (Windows Metafile Format) (.wmf) For exchanging graphics between Microsoft applications such as clipart
in Microsoft Office
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Multimedia Elements
GraphicsGIF versus JPEG When the number of color of an image is large, JPEG
performs better
JPEG format, 6k bytes GIF format, 13.5k bytes
UIT - Multimedia Production13
Multimedia Elements
GraphicsGIF versus JPEG When the number of color of an image is small, GIF
performs better
GIF, 1.5k bytes
JPEG, 5.4 bytes
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Multimedia Elements
Computer-based AnimationAnimated GIFs Animated GIFs are a special kind of GIF file known as GIF89a An animated GIF file stores multiple images as separate blocks withi
n a single GIF file When being viewed on the Web, the multiple images are streamed
(played back one at a time) Streaming: the viewer does not have to wait for the entire GIF to be
downloaded before it begins running on a Web page