Direct and Indirect Manipulation Concept

Let's start with new topic, hmmp aabout manipulation concept.

The term used to describe graphical systems with this style of interaction was first
used by Shneiderman (1982). He called them “direct manipulation” systems, suggesting
that they possess the following characteristics:
The system is portrayed as an extension of the real world. It is assumed that a person
is already familiar with the objects and actions in his or her environment of
interest. The system simply replicates them and portrays them on a different
medium, the screen. A person has the power to access and modify these objects,
including windows. A person is allowed to work in a familiar environment and
in a familiar way, focusing on the data, not the application and tools. The physical
organization of the system, which most often is unfamiliar, is hidden from
view and is not a distraction.
Objects and actions are continuously visible. Like one’s desktop, objects are continuously
visible. Reminders of actions to be performed are also obvious, where
labeled buttons replace complex syntax and command names. Cursor action and
motion occurs in physically obvious and intuitively natural ways. Nelson (1980) described this concept as virtual reality, a representation of reality that can be
manipulated. Hatfield (1981) is credited with calling it WYSIWYG (what you see
is what you get). Rutkowski (1982) described it as transparency, where one’s intellect
is applied to the task, not the tool. Hutchins, Hollan, and Norman (1986) considered
it direct involvement with the world of objects rather than communicating
with an intermediary.
One problem in direct manipulation, however, is that there is no direct analogy
on the desk for all necessary windowing operations. A piece of paper on
one’s desk maintains a constant size, never shrinking or growing. Windows can
do both. Solving this problem required embedding a control panel, a familiar
concept to most people, in a window’s border. This control panel is manipulated,
not the window itself.
Actions are rapid and incremental with visible display of results. Because tactile
feedback is not yet possible (as would occur with one’s hand when one touches
something), the results of actions are immediately displayed visually on the
screen in their new and current form. Auditory feedback may also be provided.
The impact of a previous action is quickly seen, and the evolution of tasks is continuous
and effortless.
Incremental actions are easily reversible. Finally, actions, if discovered to be incorrect
or not desired, can be easily undone.

Indirect Manipulation
In practice, direct manipulation of all screen objects and actions may not be feasible
because of the following:
-The operation may be difficult to conceptualize in the graphical system.
-The amount of space available for placing manipulation controls in the window
border may be limited.
-It may be difficult for people to learn and remember all of the necessary operations
and actions.
When this occurs, indirect manipulation is provided. Indirect manipulation substitutes
words and text, such as pull-down or pop-up menus, for symbols, and substitutes typing
for pointing. Most window systems are a combination of both direct and indirect manipulation. A menu may be accessed by pointing at a menu icon and then selecting
it (direct manipulation). The menu itself, however, is a textual list of operations (indirect
manipulation). When an operation is selected from the list, by pointing or typing,
the system executes it as a command.
Which style of interaction — direct manipulation, indirect manipulation, or a combination
of both — is best, under what conditions and for whom, remains a question
for which the answer still eludes us.