Multimedia Elements II Graphics, Digital Video

UIT - Multimedia Production2 Multimedia Elements Multimedia elements include: Text Graphics Animation Digital Video Digital Audio abvdefghij Klmnopqrst uvwxyz Multimedia

UIT - Multimedia Production3 Multimedia Elements Graphics Graphics is a digital representation of non-text information such as a drawing, chart, or photograph. It is also called a digital picture or image, and contains no 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 Graphics Pixel 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 Graphics Bitmap 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 Graphics Bitmap Graphics The more bits used to represent a dot, the more colors and shades of gray that can be represented: 1-bit image, 2 color: black or white 8-bit image, 256 colors (2 8 =256) 24-bit image, colors (true color)

UIT - Multimedia Production7 Multimedia Elements Graphics Vector 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 {(3, 2)  (10, 2)}

UIT - Multimedia Production8 Multimedia Elements Graphics Vector Graphics An example of vector graphic is the clipart in MS PowerPoint When you enlarge a clipart image, it will not distort

UIT - Multimedia Production9 Multimedia Elements Graphics Resolution 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

UIT - Multimedia Production10 Multimedia Elements Graphics Formats A format is a standard specifying how the data is arranged For bitmap graphics  BMP  GIF  JPEG For vector graphics  AI  FH  WMF

UIT - Multimedia Production11 Multimedia Elements Graphics Formats 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

UIT - Multimedia Production12 Multimedia Elements Graphics GIF versus JPEG When the number of color of an image is large, JPEG performs better JPEG format, 6k bytesGIF format, 13.5k bytes

UIT - Multimedia Production13 Multimedia Elements Graphics GIF versus JPEG When the number of color of an image is small, GIF performs better GIF, 1.5k bytes JPEG, 5.4 bytes

UIT - Multimedia Production14 Multimedia Elements Computer-based Animation Animated GIFs Animated GIFs are a special kind of GIF file known as GIF89a An animated GIF file stores multiple images as separate blocks within 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