hci user interface. why hci? what is an interface? the place at which independent and often...
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HCI
User Interface
Why HCI?
What is an interface?
the place at which independent and often unrelated systems meet and act on or communicate with each other.
— Meriam-Webster
Why do we remember only the bad?
A good interface should be transparent Bad interfaces cause user frustration
“What was this product designer thinking?”
GOOD BAD
The First Graphical User Interfaces
XEROX’s GUI (1981)
Microsoft’s Window (1985)
Apple Computer’s Lisa GUI (1983)
A Brief History of User Interfaces
Batch-processing No interactive capabilities All user input specified in advance (punch cards, ...) All system output collected at end of program run
(printouts,...) -> Applications have no user interface component
distinguishable from File I/O Job Control Languages (example: IBM3090–JCL,
anyone?): specify job and parameters
A Brief History of User Interfaces Time-sharing Systems
Command-line based interaction with simple terminal Shorter turnaround (per-line), but similar program
structure Example: still visible in Unix commands
Full-screen textual interfaces Shorter turnaround (per-character) Interaction starts to feel "real-time" -> Applications receive UI input and react immediately
in main "loop" (threading becomes important)
A Brief History of User Interfaces
Menu-based systems Discover "Read & Select" over "Memorize & Type"
advantage Still text-based! Example: UCSD Pascal Development Environment -> Applications have explicit UI component But: choices are limited to a particular menu item at
a time (hierarchical selection)
A Brief History of User Interfaces
Graphical User Interface SystemsFrom character generator to bitmap display Pointing devices in addition to keyboard
-> Event-based program structureMost dramatic paradigm shift for application
developmentUser is "in control"Application only reacts to user (or system)
eventsEvent handling
Conceptual model
Need to first think about how the system will appear to users (i.e. how they will understand it)
A conceptual model is a high level description of: “the proposed system in terms of a set of
integrated ideas and concepts about what it should do, behave and look like, that will be understandable by the users in the manner intended”
Physical, perceptual, and conceptual aspects of the user interface
Interface
User interfaces handle inputs and outputs that involve the system user directly
Interactions with the user and computer (HCI) can be modeled with dialog designs
User-interface design occurs in each iteration
Well, “…it could be better …”
“Better …”
Good Designs => Usable Systems
Work the way the user thinks they should Allows the user to focus on task at hand
and not worry about the underlying technology and interaction technology
Minimize user errorsPromote user satisfaction (users should
feel that they are accomplishing more with the system than without the system)
What Is “Design” in HCI? • It is a process:—a goal-directed problem solving activity informed by intended use, target domain, materials, cost, and feasibility
—a creative activity—a decision-making activity to balance trade-offs
• It is a representation:—a plan for development—a set of alternatives & successive elaborations
what is design?
achieving goals within constraints
goals - purpose who is it for, why do they want it
constraints materials, platforms
trade-offs
Graphical RepresentationFrom the design point of view
Screen two-dimensional Objects two-dimensional/three-dimensional Representation of 2D objects on a 2D screen
Straightforward graphics is enough Representation of 3D objects on a 2D screen
Required special techniquesHuman vision psychology is required to be
considered
Four basic activities There are four basic activities in Interaction Design:
1. Identifying needs and establishing requirements2. Developing alternative designs3. Building interactive versions of the designs4. Evaluating designs
Some practical issues
• Who are the users?
• What are ‘needs’?
• Where do alternatives come from?
• How do you choose among alternatives?
What are the users’ capabilities? Humans vary in many dimensions: — size of hands may affect the size and positioning of input buttons
— motor abilities may affect the suitability of certain input and output devices
—strength - a child’s toy requires little strength to operate, but greater strength to change batteries
— disabilities(e.g. sight, hearing, dexterity)
What are ‘needs’?• Users rarely know what is possible• Users can’t tell you what they ‘need’ to help them achieve
their goals • Instead, look at existing tasks:
– their context– what information do they require?– who collaborates to achieve the task?– why is the task achieved the way it is?
• Envisioned tasks:
– can be rooted in existing behaviour– can be described as future scenarios
What is interaction design?
Designing interactive products to support people in their everyday and working lives
Sharp, Rogers and Preece (2002)
The design of spaces for human communication and interaction
Winograd (1997)
Testing prototypes to choose among alternatives
Many kinds of interaction styles available…
Command line interface Speech Data-entry Form fill-in Query Graphical Web Pen Augmented reality three–dimensional interfaces
UI implementationConsole applications (CUI’s)
Command-line and natural language interfaces
Interaction devises (input & output devises)User interfaces for virtual environments
Graphical User Interfaces (GUI’s)Window systems, toolkits, frameworksGUI builders
Command line interfaceWay of expressing instructions to the
computer directly function keys, single characters, short
abbreviations, whole words, or a combinationExact spellingsuitable for repetitive tasksbetter for expert users than novicesoffers direct access to system functionalitycommand names/abbreviations should be
meaningful!Hard to rememberTypical example: the Unix system
Linux/UNIX:Shell Command Language
Windows XP “DOS” Shell Command Language
Natural languageFamiliar to userspeech recognition or typed natural
languageProblems
vague ambiguous hard to do well!
Solutions try to understand a subset pick on key words
Query interfacesQuestion/answer interfaces
user led through interaction via series of questions
suitable for novice users but restricted functionality
often used in information systemsQuery languages (e.g. SQL)
used to retrieve information from database requires understanding of database structure
and language syntax, hence requires some expertise
Form-fills
Primarily for data entry or data retrievalScreen like paper form.Data put in relevant placeRequires
good design obvious correction
facilities
Three dimensional interfacesvirtual reality ‘ordinary’ window systems
highlighting visual affordance indiscriminate use
just confusing!3D workspaces
use for extra virtual space light and occlusion give depth distance effects
flat buttons …
… or sculptured
click me!
Graphical User Interface (GUI)Standard elements in GUI based direct
manipulationBitmapped screenWIMP
Windows Icon Menus Pointers
Graphical User Interface (GUI)
Standard elements in GUI based direct manipulation
WIMP Windows
Multiple windows Tiled vs. overlapping Reduce and restore Move Resize Scroll contents
Icons
small picture or image represents some object in the interface
often a window or actionwindows can be closed down (iconised)
small representation if many accessible windows
icons can be many and various highly stylized realistic representations.
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Icons
Icons get used for lots of different things Representing objects
Files Tools
Representing commands Open Undo ..often shortcuts to menu commands that have no icon
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Icons
There are guidelines for these too Apple:
Design and composition should indicate purpose Perspective should agree with real-life interactions Differentiate them from other UI elements
Microsoft: Colors that complement the XP design Perspective is either at a certain angle, or straight-on Everyday objects should look modern
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Microsoft Icon Composition
Exceptions: Document icons Symbols such as warning Single objects Objects not recognizable at an angle
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Apple Icon Composition
Icon “genres” Application: media (paper) and tool (pen) Utility: straight perspective, subdued colors ..also document, plug-in, toolbar
Dialog Styles
Q & A Old style. Used with setup. Answer selected (menu).
Graphical User Interface (GUI)
Standard elements in GUI based direct manipulation
WIMP Pointers
Property sheets/dialogue boxes Check box Selection / radio buttons Fill-in blanks
Pallets Tool bars etc.
Pointers important component
WIMP style relies on pointing and selecting things uses mouse, trackpad, joystick, trackball, cursor
keys or keyboard shortcuts wide variety of graphical images
Graphical User Interface (GUI)
Standard elements in GUI based direct manipulation
WIMP Menus Pull-down (from bar or top) Pop-up/contextual (from item)
Menus Set of options displayed on the screen Options visible
less recall - easier to use rely on recognition so names should be meaningful
Selection by: numbers, letters, arrow keys, mouse combination (e.g. mouse plus accelerators)
Often options hierarchically grouped sensible grouping is needed
Restricted form of full WIMP system
Menu Selection
Menus Choice of operations or services offered on the screen Required option selected with pointer
problem – take a lot of screen space
solution – pop-up: menu appears when needed
File Edit Options
Typewriter Screen Times
Font
Kinds of Menus Menu Bar at top of screen (normally), menu
drags down pull-down menu - mouse hold and drag down menu drop-down menu - mouse click reveals menu fall-down menus - mouse just moves over bar!
Contextual menu appears where you are pop-up menus - actions for selected object pie menus - arranged in a circle
easier to select item (larger target area) quicker (same distance to any option)
… but not widely used!
Buttons
individual and isolated regions within a display that can be selected to invoke an action
Special kinds radio buttons
– set of mutually exclusive choices check boxes
– set of non-exclusive choices
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Push ButtonsYou click it, and something happensChoose the title text carefully
Apple: “Button names should be verbs that describe the
action performed”Microsoft:
“Aim for the shortest possible label; one word is best.”
“If possible, use label text that makes sense when read out of context — for example, when a user reads or hears only the label of the current control.”
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Layout
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Layout
Apple has a program called Interface Builder which automatically helps you use the correct spacing
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Layout
Toolbars
long lines of icons …… but what do they do?
fast access to common actions
often customizable: choose which toolbars to see choose what options are on it
Dialogue boxes
information windows that pop up to inform of an important event or request information.
e.g: when saving a file, a dialogue box is displayed to allow the user to specify the filename and location. Once the file is saved, the box disappears.
Screen design
use boxes to group logical items use fonts for emphasis, headings but not too many!!
ABCDEFGHIJKLMNOPQRSTUVWXYZ
physical controls
grouping of items defrost settings
type of food
time to cook11type of food
time to cook
defrost settings
physical controls
grouping of items
order of items
4
4) start2
2) temperature
3
3) time to cook
11) type of heating
physical controls
grouping of items
order of items
decoration
different colours for different functions
lines around related buttons (temp up/down)
physical controls
grouping of items
order of items
decoration
alignment
? easy to scan ?
centred text in buttons
physical controls
grouping of items
order of items
decoration
alignment
white space
gaps to aid grouping
alignment - text
you read from left to right (English and European)
align left hand side
Willy Wonka and the Chocolate FactoryWinston Churchill - A BiographyWizard of OzXena - Warrior Princess
Willy Wonka and the Chocolate FactoryWinston Churchill - A Biography
Wizard of OzXena - Warrior Princess
fine for special effects but hard to scan
boring butreadable!
multiple columns
scanning across gaps hard:(often hard to avoid with large data base fields)
sherbert 75toffee 120chocolate 35fruit gums 27coconut dreams 85
multiple columns - 2
use leaders
sherbert 75toffee 120chocolate 35fruit gums 27coconut dreams 85
multiple columns - 3
or greying (vertical too)
sherbert 75toffee 120chocolate 35fruit gums 27coconut dreams 85
colour and 3D both often used very badly! colour
older monitors limited palette colour over used because ‘it is there’ beware colour blind! use sparingly to reinforce other information
3D effects good for physical information and some graphs but if over used …
e.g. text in perspective!! 3D pie charts
bad use of colour
over use - without very good reason (e.g. kids’ site)
colour blindness poor use of contrast do adjust your set!
adjust your monitor to greys only can you still read your screen?
Example : Color Stereoscopy
Example : Text Stand Out
Example: One Color
Example: Two Colors
Example: Three Colors
Example: Four Colors
Text & ColorsWhat materials to present as spoken vs. text?
“less text is normally more effective”Text presentation
Number of fonts– one or two E.g., stick with Times New Roman, or stick with
New Century Schoolbook Don’t overuse bold, italics, underline etc. Spell check & proof read!
Colors Background– pale colors Foreground– brighter colors Use a small number of colors
Example: One Font
Example: Two Fonts
Example: Three Fonts
Example: Four Fonts
Attention with Structured Information Structure the information so that it is easy
to navigate through Presenting not so much information and not
too little on a screen Instead of arbitrarily presenting data on the
screen, it should be grouped and ordered into meaningful parts Blank space Color Font variations etc.
Attention with Structured Information
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Ten Good Deeds in Web Design
1. Place organization’s name and logo on every page and make the logo a link to he home page
2. Provide a search function if the site is more than 100 pages
3. Write straightforward headlines and page titles
4. Structure the page to facilitate reader scanning
5. Use hypertext to structure the content space
Ten Good Deeds in Web Design (continued)
6. Use product photos with thumbnails on the primary page
7. Use relevance-enhanced image reduction
8. Use link titles to provide users with a link preview
9. Ensure accessibility for users with disabilities
10. Do (Design) the same as everyone else
Example Visionary approaches for developing novel
conceptual paradigms
Questions
Name four factors which must be taken into account when designing a good user interface. Explain why each factor is important. (8)
Explain one way in which the needs of an expert user and a novice user can be accommodated when designing the HCI for a piece of software. (2)