The user creates new
objects by picking them from an infinite stack of objects, i.e. the pile that
is like a factory producing objects. To create a new object, the user either
drags it from the pile, or he selects the pile and clicks somewhere, where the
object can be created.
The pile where the objects
come from does not need to be static; the user may edit the properties of the
pile to create different kind of objects.
In most cases, the created
objects become independent of the pile, meaning that changes made on the pile
properties affect only the objects that are created in the future, not objects
that created in the past. However, if the changes in the pile also affect
objects created in the past, this connection is an example of the Master and Instances
problem.
Example 1: Tabulators in Microsoft Word
The user creates new tab
stops in Microsoft Word by clicking the tab area, which creates a new tab object
from the pile on the left. The tab pile is now in the state of creating left
alignment tab stops, which can be seen from the icon of the pile.
Example 2: Train editor [Nevalainen99]
The user creates a new
cargo car by dragging the car object from the pile to the train. The palette on
the left consists of four ‘infinite’ stacks of different car types.
Nevalainen99 |
Nevalainen
S., Ranta J., Design project of the User Interfaces course. Department of Computer Science, University of Helsinki, 1999. |
Updated 21.07.2003 / Sari A.
Laakso, email salaakso@cs.helsinki.fi