(Last updated for ver 0.2.1)

Behaviors are used to affect how a Feature is drawn. Their capabilities go beyond the simple transforming and coloring handled by Adjust and Color objects. They perform logic which is executed every time an AvatarDisplay draws a Feature.

API: Behavior Interface

In This Document:

• Behavior Model
• Core Behaviors
• Mirror Behavior
• Constrain Behavior
• Assigning Behaviors
• Custom Behaviors
• Where to go from here

Behavior Model

Behaviors are objects which extend the IBehavior interface. It includes 2 methods used by behaviors when they're used with a feature:

• getArtSprites - Returns a list of ArtSprites used to draw the Feature
• drawArtSprite - Used to draw each ArtSprite defined by getArtSprites

Every time a draw operation is handled by an AvatarDisplay object, it will run through the standard drawing procedures for each Feature, as well as each behavior assigned to that Feature.

The order of operations followed when drawing a Feature is:

1. Apply Feature's Adjust
2. Apply Feature's Color
3. Run each behavior
4. Apply parent Feature's Adjust

Core Behaviors

Avatar Core ships with 2 built-in behaviors, Mirror and Constrain. As with all behaviors, they're extensions of the framework and not necessary for core functionality.

Mirror Behavior

The Mirror behavior is used to mirror a Feature along either the x or y axis. Mirrored Features have their Art duplicated and rendered within a mirrored position with respect to the original Art. This behavior is good for symmetrical facial features like eyes and ears.

Constrain Behavior

The Constrain behavior is used to restrict the Adjust used to draw a Feature. This is important to make sure editable features aren't edited beyond reasonable bounds. Constrain can restrict x, y, scaleX, scaleY, (scale,) and rotation. Each are handled with a Range object which can also be used to apply stepping (reducing the possible number of values between any given range).

Assigning Behaviors

Each Feature can support any number of behaviors. To facilitate this, they're stored in a collection owned by each Feature, Feature.behaviors.

<Feature>
	<behaviors>
		<Mirror />
		<Constrain>
			<x min="0" max="100" />
			<y min="-50" max="50" />
		</Constrain>
	</behaviors>
</Feature>

The order in which they appear in the behaviors list represents the order in which those behaviors are executed when the Feature is drawn.

Custom Behaviors

Behaviors are extensions to the core functionality of the Avatar Core framework. As a result, it can be easy to make custom behaviors. All you need to do is make a class that implements IBehavior and add an instance of that class to a Feature's behavior list.

When using custom behaviors:

• Make sure the behavior definition is compiled into your client
• Make sure you use the correct namespace for the behavior in XML

Where to go from here

• AboutFeatures
• AboutArt
• AboutXMLParsing
• AboutLibraries
• AboutColors
• AboutAdjusts
• AboutBehaviors