Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Introduction to Computers CS1100 Dr. Zhizhang Shen Chapter 2: Between the Two: Exploring the Human-Computer Interface

1-2 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-2 What about it? Computer is by the people and for the people, and definitely of the people. There are too many things going on between computers and us We have to understand some of the basic stuff between the machine and us so that we can make a better use of the machine.

1-3 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-3 Learning about technology –We have to learn about technology to do our job well and enjoy our life better. –Our experience using devices such as TV, and software, Nintendo wii, tells us what to expect, i.e., the new stuff should not lead to a dramatic change. –Designers who create devices, including software, know about this experience and design products to match what we already know.

1-4 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-4 The Desktop is just like a desk top Image displayed on the monitor when a PC starts up, a bunch of items on our table –Colored or patterned background –Information displayed on top, bottom, or side –Three types of icons: Applications (programs): what to do Files (documents): what we have Folders (directories): organized files

1-5 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-5 "Desktop" is a metaphor It is analogous to working at a desk: –Works we did will be kept in files –Files are organized in folders, kept in file cabinets –Tools such as a calculator, pencils, scissors, … are readily accessible on the tables.

1-6 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-6 Playing Recorded Music Example of metaphoric user interface –Software that plays CDs on computer has Graphical User Interface (GUI) –This GUI resembles a familiar music player Buttons resemble an ordinary CD player User can apply knowledge of CD player to learn to use this GUI without special instruction because the metaphor is familiar

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1-8 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-8 Understanding the Designer's Intent Software designers try to pick easy-to- understand user interfaces so the learning curve will not be too high. We are all busy. We can expect good software to be well crafted so we can "brain out" how it works For users, interface is everything. We have a separate course, HCI, for the CS majors to study such issues.

1-9 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-9 Consistent Interfaces There are standard metaphors found in all GUIs, such as File and Edit, Tools and Help. All interfaces of Window programs look similar, if not exactly the same. When we see an icon or metaphor we have seen before, we know how it works Thus, once you learn one, you know all.

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1-11 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-11 Command buttons: What to do? May look like a 3D rectangle or circle, with an icon or text centered on the button We click mouse to "press" the button and the command is invoked –Tells the associated software to perform the operation We receive feedback to confirm the button has been clicked –Color change, shadow, highlight, or audible click

1-12 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-12 Slider Control Sets a value from a "continuous" range, like volume Move slider by placing mouse pointer on it and dragging in the direction of change –Scroll bars are a type of slider control

1-13 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-13 What is a menu? –All operations performed by the software are listed in the menu –Grouped by similarity of operations, e.g., all those on files will be collected under File. –Often organized in a hierarchy. –Consistency throughout the applications.

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1-16 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-16 Different kinds of menu Menus on the top bar are called pull-down or drop-down menus –Mouse click reveals list of operations –Sliding mouse down the list highlights items –Clicking or releasing button on highlighted item causes computer to perform that operation Same operation may be available by icon on a toolbar below the menu Menus that display on a (right) mouse click are called pop-up menus

1-17 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-17 What is in a menu? Menus provide information about: –List of operations that you can apply –Whether an operation is available –Where more user input is needed –Shortcuts

1-18 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-18 What could happen? Items that need more specification have an ellipsis at right end (…) –Example in the Edit menu: Find…(What do you want?) Selecting item pops up an additional menu requiring more input Software continues to ask for information by opening new windows until it has enough Then performs operation immediately and closes menu(s) and window(s)

1-19 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-19 A shortcut? Menu items may have keyboard shortcuts –Combination of keyboard characters that have the same effect as clicking menu item –Shortcut appears next to menu item (Ctrl-V for paste) –Shortcut consists of combination of special key (meta key) and a letter For Mac: special key is Command (clover) For Windows: special key is Control –Shortcuts are usually consistent across operating systems: Ctrl-V is always for paste

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1-21 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-21 A standard GUI package Operations that are available in any software because they are needed to process any type of information –Save –Open –Print Standard operations usually grouped as File and Edit

1-22 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-22 File Operations What we do with computer is to process data, always kept as files. Generally apply to whole instances of the type of information being processed –Word Processor:Instance is a document –MP3 Player:Instance is a song –Photo Editor:Instance is a picture

1-23 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-23 File Operations (cont'd) New: Creates a blank instance Open: Locates and reads file on disk Close: Stops processing current instance, closes window, but keeps program running Save: Writes current instance to disk, using previous name and location Save As: Writes current instance to disk, using new name and location

1-24 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-24 File Operations (cont'd) Page Setup: Specify how printed document should appear on paper Print: Prints copy of current information Print Preview: Shows how the information will appear when printed Exit or Quit: Ends application

1-25 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-25 Edit Operations Let you make changes within an instance, a file, a song, etc.. Often involve selection and cursor placement Edit operations are performed in standard sequence: –Select, Cut/Copy, Indicate Placement, Paste, Revise

1-26 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-26 Undo:Cancels the most recent editing change (may not be available for some operations) Repeat:Applies the most recent editing change again Copy:Stores a temporary copy of selected information, ready for pasting Edit Operations (cont'd)

1-27 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-27 Edit Operations (cont'd) Cut: Removes selected information and saves in temporary storage, ready for pasting Paste: Takes data held in temporary storage by Cut or Copy, and inserts it into current instance Clear: Deletes selected information Select All: Selects the entire instance

1-28 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-28 Did it do anything? Feedback is any indication that the computer is still working, or has completed task –For editing change, proof of completion is that the revision is visible –For button click, software provides an indication like highlighting, shading, graying, underlining, changing color, or audible click

1-29 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-29 Still going? Most common feedback: Indication that computer is working on time-consuming task –Cursor is replaced with icon like hourglass (Windows) or rainbow spinner (Mac) Other forms of feedback: busy spinner, running dog or horse, time-estimating meter "fills", completion count Be patient

1-30 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-30 Form follows function… Fundamental operations of a software system and the way they work are determined by the task being solved New versions of familiar software will share core functions, and many features reminds us of earlier versions (downward compatibility) When we must perform a familiar task with unfamiliar software, we are already experienced and familiar with its basic features

1-31 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-31 Same O, same O… Text processing applications all: –Use a cursor to mark your place –Have operations for typing, deleting, selecting, copying, searching, replacing, etc. –These operations work similarly to earlier versions… e.g., backspace key removes character to the left of the cursor So how do vendors compete? –Add non-fundamental features (Have you checked Chromes?) –Make systems more convenient, friendlier, faster, less error- prone, etc.

1-32 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-32 Take IT Personally W can expect intuitive interfaces To learn to use new software, we should ask ourselves: –What do I have to learn about this software to do my task? –What does the designer of this software expect me to know? –What does the designer expect me to do? –What metaphor is the software showing me? –What additional information does the software need to do its task? –Have I seen these operations in other software?

1-33 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Example: Google Chrome I need to learn little to work with it. The designer expects me to know how a browser works in general. She expects me to do essentially the same. Chrome carries the history file from other browser, and will remember what sites I visited the most. 2-33

1-34 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2-34 Homework: Multiple choice: odd numbered Short answer: even numbered Use Google to find Lincoln’s Gettysburg Address, download it, and then Exercises 7 and 8.