Chapter 21: Direct Manipulation and Pointing Devices

Rich visual interaction is the key to successful direct manipulation.

Direct manipulation is easy to use, fun and entertaining, it is difficult for user to do a good job with them.

Program manipulation vs. Content manipulation
Program manipulation involves scroll bars, button pushing, etc.
Content manipulation involves drawings, moving data, creating data.

Three phases of direct manipulation process:
Free Phase - before the use takes any action
Captive Phase - after the user has begun the drag
Termination Phase - after the user releases the mouse button

"Captive Cursor Hinting" = cursor changes when dragging (arrow and + when copying in Illustrator, dragging an outline of an object)

Pointing Devices:
Light pens and CRTs
mahlstick - a half-meter-long wooden dowel with a padded end. The artist rests the padded end on the wall and hold the other end in her free hand. Then she rests the heel of her drawing hand on the center of the stick. This enables her to change the relative incidence of the paiting surface from pure vertical to one that is better suited to keeping her drawing hand under control.

Mouse - indirect
Mouse is only better when surface is vertical

trackballs, digitizing tablets, touchpads, trackpoint (eraser button in center of keyboard)

fine versus gross movements

"If a control demands a click nearby followed by a click far away, the control is poorly designed."

"Pliant" controls are active controls.
Visually hint at pliancy:
Static visual hinting / dynamic visual hinting
Cursor hinting

Wait cursor hinting - hourglass, spinning color wheel

Meta-keys - Control, Alt, Shift