1. 1 CSC111H User Interface Design Dennis Burford dburford@cs.uct.ac.za

2. 2 Why and What? Why bother with the design of user interfaces? What makes a “good” user interface?

3. 3 Designing for Users Software is useless if users can’t use it Design for users! Basis of user interface design should be to allow user to achieve their goals. –look at tasks which user is trying to achieve –look at user’s capabilities

4. 4 Chat Program What are your user’s goals and tasks? How can you make it easier to achieve these?

5. 5 Examples of Bad Interfaces…. What is wrong with these interfaces? Why is it a problem? What are you supposed to do? What is the sequence of actions?

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8. 8 In general... Don’t force user to accept bad interface because it is easy to implement! Don’t just add stuff because you can KISS: Keep it simple stupid

9. 9 Some Design Principles Based on Human capabilities Physical and mental limitations of people using system

10. 10 Human Capabilities Memory (7 ± 2 things) Avoid clutter (Economy) Avoid Cognitive Overload Consistency Affordances User familiarity Past Experience Match interface to user group Intuitive display of status, info and controls Direct Manipulation No Surprises Mistakes Confirmation Recoverability Perception and Visual Recognition

11. 11 Affordances Visual representation of world of action Devices “afford’ usage… –e.g. door handles, knife-fork-spoon, pen, scissors GUIs: scrollbars, sliders, buttons, dials

12. 12 Direct Manipulation Show objects of interest Actions –Rapidly executed –Performable incrementally –Reversible Show results of actions immediately (E.g. Colour Chooser)

13. 13 Direct Manipulation While task incomplete: 1. Observe 2. Take Action 3. Get Feedback 4. Adjust Mental Model Ensure each step (and whole process) is “natural” / intuitive

14. 14 Information Presentation Obvious and Intuitive –real world analogies –e.g. Dial, temperature gauge, progress bar Color and Layout Avoid Clutter

15. 15 Evaluation Part of testing Can the users perform their task –successfully –efficiently Learnability, speed of operation, robustness, recoverability, adaptability