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Alan Cooper On Users. http://www.youtube.com/watch?v=sNWBnCazIcU. CSc 238 Human Computer Interface Design Part III - Designing Interaction Details. Chapter 16 Understanding Undo “Robust support for the terminally undecided.”. Users and Undo.
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Alan Cooper On Users http://www.youtube.com/watch?v=sNWBnCazIcU
CSc 238 Human Computer Interface DesignPart III - Designing Interaction Details Chapter 16 Understanding Undo “Robust support for the terminally undecided.”
Users and Undo • What are the different ways you think about uses of the Undo? Rescuer from “distress” … heroic recoveries. • Reality… we make mistakes all the time… as part of our everyday behavior. • Should we think of “mistakes” as errors (abnormal behavior)? If yes, we continue to do what we do “… abandon the idea that the user can make a mistake… “
Undo enables exploration • Undo allows user to reverse one or more previous actions if they change their mind. • A “better” mental model for the user. • The Undo reassures users… and they don’t need to think about it until its needed. • Stop those “are you sure” messages!
Designing an Undo Facility User’s mental models: • Unconditional panic button • Seen as a storage facility for deleted data • Stack of procedures that can be undone one at a time in reverse order (LIFO) Needed but not available: • Cannot reverse actions after they save the document (the Undo buffer is not saved with the file). • What else?
Types of Undo • Incremental – cutting, pasting, typing, deleting (actions that involve a data component) • Procedural – formatting, rotating or cropping a picture (actions are data free) • Blind Undo – no indication of what is being undone • Explanatory Undo – text or visual included indicating what will be undone
SingleandMultiple Undo • Single – the most basic, but why! • Multiple – reverses more than one previous operation, but in reverse order (stack – LIFO) • Each click, Undoes one action (modeling code and not user goals) • Why not a queue, and allow me to select what I want to undo from the set of prior actions?
Redo • Allows user to recover from too many clicks on the Undo button • Multiple Undoing • Choose the 5th item in a list and all four item before it are selected & Undone • User mental model: they thought only the item selected would be Undone!
Other Models Allow for Comparison: • Toggling between Undo and Redo – to decide. TV remote and the “Jump” or “Back” button Comparing images, each with different settings • Categorizing specific types of actions with Undo buttons for each category Format-Undo Typing-Undo
Other • Data buffer of deleted text. • Versioning & Reversioning (remembering the before case – the entire before document). “Many tools exist...” Did they overlook CVS, Subversion? User, understanding the differences between versions, chooses to revert (fall back) to a specific earlier version. • Freezing … fixing.
Are there Undo-proof Operations? • Save document for the first time… you choose the name. • What programs allow you to change/rename a document already saved? • What programs allow for an Undo when you save a document with the same name as an existing document, replacing the existing document with the newly saved document?