Both IMS Web Spinner and IMS Web Engine include two simple
behaviors that can be assigned to your Objects. These
behaviors can set an Object's visibility while the page is
first loading, after it has loaded or on a mouse over or
mouse leave event. These Behaviors are a useful way to create
several special effects that toggle an Object's visibility.
IMS Web Engine includes the ability to create far more
complex behaviors based on many different interrelated
events. The effective use of these Behaviors is probably the
most complex aspect of learning to use IMS Web Engine.
We have tried to simplify several common uses for Behaviors
by incorporating them into the IMS Web Engine Wizards. These
include the creation of drop menus, strobe effects, and the
management of several animation effects. Mastering the use of
the Behavior dialog however, will give you the ability to
create complex interactive web pages including DHTML games,
business presentations and educational courseware.
A Behavior works by switching between an 'Active' and a 'Not
Active' state. Don't be misled by the terms. There is nothing
intrinsically different between the two states other than
what you decide to assign to them. In other words, an Object
could just as easily be invisible when 'Active' as when 'Not
Active'.
The Behavior is composed of two components. The first is an
Event that triggers a Behavior 'Active' or 'Not Active'. The
second is an Action that will be performed when the Behavior
enters either of these two states. The user defines a
Behavior by deciding what the trigger mechanisms are and what
actions will be performed as the Behavior switch between the
two states.
As an example, we can use a simple Mouse Over Behavior to
make an Object Visible and Invisible.
The trigger events in this example are the mouse moving over
and off the Object. By default, the Object starts in a 'Not
Active' state. As the cursor is moved over the Object, it
triggers the Object into its 'Active' state. As the cursor
moves off the Object it triggers its 'Not Active' state. The
Behavior's 'Actions' are to make the Object 'Visible' when it
is triggered into its 'Active' state and 'Invisible' when
triggered into its 'Not Active' state.
As I mentioned previously, there is no intrinsic difference
between an Object's 'Active' and 'Not Active' state. Figure
is20fig2 illustrates this with two examples. Example 1 will
make an Object Visible as the mouse moves over it. Example 2
does the reverse.
This example is of course very simple and can be more
efficiently done by setting an Objects Visibility in the
Object Editor. The principle for more advanced Behaviors
remains the same. The difference lies in the types of Events
that can trigger a Behavior and the Actions that can be
performed by the Behavior.
Is20fig3 illustrates some of the Behavior dialogs including Triggers
and Actions that can be applied to a Behavior. User Triggers
include Mouse Over, Mouse Select or a keyboard character.
Dynamic triggers include Time, when two Objects intersect or
don't intersect, or when an Object's internal value equates to a
simple test. An event can also be triggered by another Object
when its Events are triggered.
There are many Actions a Behavior can perform when an Event
is triggered. These include setting an Object's visibility,
starting or stopping its Action or Sound Component if it has
one, or triggering the Event of another Object's Behavior.
Actions can also include applying a mathematical formula to
any Object or performing a Metamorph operation on an Object.
Despite the big word, this simply means changing one or more
of an Object's Components. An example would be switching an
Objects Action component that traces a rectangle to an Action
component that traces a polygon.
These operations may seem complicated when taken in their
entirety. When looked at individually however, they are far
easier to understand.
I will look at some specific Behaviors and how to implement
them interspersed with articles that also apply to IMS Web
Spinner and IMS Web Dwarf users over the next few issues.
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