
ff9acbea201f77af1e0ef01873a281a5.ppt
- Количество слайдов: 59
Animation n Animated GIF n Javascript n Java n Vector animation: Flash, SVG n Shockwave n 3 D
Raster vs Vector n Vector: items drawn with lines n Smooth n Scaled very well n Cannot be filled with multiple colors n Raster: pixel based n 3 D shading
Raster vs. Vector Raster
Raster vs. Vector
Informing the User n Provide information to user n Inform of potential load/play times n Required plugins
Multimedia Information
3 D for the Web n Use of 3 D very limited (still) n Commonly used for product views n Very computational intensive n VRML n Shockwave
Web 3 D Formats
Controls
3 D and Performance 3 D files require: n Large amounts of memory n Large amounts of bandwidth
Level of Detail
Successive Refinement
Mpeg-4 n Future standard: Combines: n Audio n Video n Vector Graphics n 3 D Graphics
MPEG-4
Human Representation n Means to represent virtual humans n Called avatars n Used to interact with user Typically used in online games representing: n Other users n Non-player charactures
HANIM
Poser
Accessibility n Web should be usable by everyone This includes users with: n Vision impairments n Hearing impairments n Mobility impairments
Statistics n 8 million people with visual impairments n 20 million deaf or hard-of hearing n 250, 000 with spinal cord injuries n 500, 000 with cerebral palsy n 330, 000 with MS n More that half US population over 65 has some type of impairment
Issues involving Vision n Web very visually oriented n Significant challenges n Severity ranges from total blindness to low vision n Color blindness n Visual Stimuli
Information Delivery n Information display on traditional monitor not available to users with visual impairments Two assistive technologies: n Screen Readers n Refreshable Braille displays
Screen readers Reads text component of web screen Includes: n Links n Menus n Dialog Boxes n Error Messages
Screen Readers n Several vendors offer screen readers n Prices range from $300 to $1000 n Page must be reformatted to support screen readers n HTML “lang” attribute controls language page will be read in
Refreshable Braille Display n For people who are deaf as well as blind screen readers do not work. n Translates text of page into Braille n Single line of Braille text n Prices range from $4500 to $14, 500
Grade II Braille
Refreshable Braille Display
Reformatting Text n For screen readers to work text of page must be formatted to support linear delivery n Tabular data n Label for Elements n Skip navigation n Alt Tags for images
Tabular Data
Course Course
Markup Strategy for Tables
Course Time Day Prerequisiste Instructor 211 11: 30 pm -1: 00 pm MW None Mc. Donald 211 10: 30 am - 12: 00 pm TR None Luecking 212 5: 45 pm - 9: 00 pm M 211 Carter 212 11: 30 pm - 1: 00 pm TR 211 Chan
Skip Navigation
Normal Page
Alt Tags (None)
Alt Tags (Descriptive)
Other Vision Issues n Screen Magnifiers n Color Blindness: – 8% male population – 0. 5% Female population – Most common red/green n Photo Sensitive Epilepsy
Color Blindness This is an Ishihara plate commonly used to check for red/green color blindness
Color Blindness This is what a red/green color-blind person might see. Note that the digit (3) is practically invisible.
Mobility Impairments n Conditions with affect use of keyboard and mouse n Might be difficult, Might be impossible n Predictive typing n Speech recognition n Alternative input technology
Hearing Impairments Few more issues: n Captioned media n Open or Closed captioning n American Sign Language
Web Accessibility Initiative n Promote usability for people with disabilities n Goal of Universal Access n Set of guidelines which address 2 themes: – Graceful Translation – Make content understandable and navigable
Web Accessibility Initiative Guidelines
Globalization n Web is growing all over world n Number of Non English speaking users rapidly increasing n Usability issues involve use of language and culture n This processes is called globalization
Global User Population
Internationalization n Internationalization single design used world wide n Simpler text n Unambiguous display of number, currency, dates, and times n Isolate and remove culturally specific language
Localization n Added cultural context n Translation of web page into local language n Relevant content
Text and Translation n Translation: human or automatic? n Attention to writing style n Expression of dates, times n Express currency in local terms n Label units of measurements
Languages Can Expand Labels
Page Layout n Unicode for character support n Color issues n Icon issues (including flags) n Text Alignment (left vs. right)
International User Testing n International and local sites need user testing n More involved than traditional n Test success of translation n International Inspection as alternative n Difficulties dues to language gap
Personalization n Strategy for gaining competitive advantage n Added service for a user n Speeds task completion (I-Click) n Can require login n Cookies n Dynamic
Privacy Concerns n No right to privacy in US n Privacy Contracts n Request of personal information cause users to leave site n Highly related to trust
Trust Many factors affect trust: n Context n Perceived Similarity n Standing in organization n Behavior n Certification n References
Fostering Trust n Help establish credibility n Security Statement n Safe display of personal information n Use of secure servers n Confirmation of all costs n Confirmation of shipping address
Controlling Privacy n No standard for enforcing privacy in place n P 3 P standard developed n Enforces and exposes site’s privacy policy n Tools to inform users of compliance with their selected privacy policy
Trust (P 3 P)
Trust (P 3 P)
Privacy Bird
Privacy Bird Shows Embedded Content
Privacy Bird