Mayhew's Book (chapt. 9)

Designing Direct Manipulation Interfaces

• Provide visual feedback for position, selection and movement, and clear feedback for modes.

• Provide an alternative interface for high-frequency, expert users.

• Choose a consistent icon design scheme.
  e.g., symbolic

• Design icons to be concrete and familiar, not abstract
  e.g., analog clock for time, not digital

• Avoid excessive detail in icon design.

• Design icons in a set to be visually and conceptually distinct.
  e.g., borders detract from the visual distinctiveness of icons

• Design icons to communicate object relations and attributes whenever possible.
  e.g., all types of documents have same icon shape
  e.g., indicate status of object in its icon (use shading or color)

• Accompany icons with names.

• Limit the number of icon types to 12 if possible, but at most to 20.

• Allow users to choose between iconic and text display of objects and actions [with care!].