Animation -overview

Purpose

The animation component is a framework -that provides support to build animated graphics applications. It provides -the basic data types that allow animations to be incorporated into the normal -drawing of a window from the client, or to be managed on the server as a sprite.

Required background

Windows -server component knowledge is recommended before using this component.

Key concepts

The component has the following key -concepts:

Animation: The animation is a fairly abstract interface owned by a client application. -The interface is independent of the source of the data it uses, as the data -providers are responsible for providing data to the animation.
Animator: The animator represents each data type supported by the animation framework. -It can handle data interpretation, timing and control of the animation. An -animator is not be visible to the owner of the animation, but is controlled -through it using a standard interface. The animators can either reside on -the client or on the server. Each animation selects an animator plug-in to -be used by providing an appropriate string obtained from the data provider.
Data provider: A data provider is a generic interface to handle different kinds of -data, which has different structures and behaviours, for example, GIFs and -SVG (Scalable Vector Graphics). Animations access the data providers they -own through an observer interface, which reports events to the animation. -The interface in turn reports these events to the respective animators.
Observer: An observer acts as an interface and is responsible for reporting events. -The animation framework provides two such observers: a data provider observer, -and an animation observer. The data provider observer is an interface between -the animation and the data provider. Using this observer the animation can -receive data and events from the data provider. The animation observer is -an interface between the animation and the client application, and is used -to report events to the client application. In Symbian OS v9.1, the animation -observer is implemented to report only errors to the client application.

Architectural relationships

The animation component -provides a set of abstract classes with some basic functionality required -for any type of animation. Implementors have to derive their own classes using -these abstract classes to support specific animation types such as bitmap -animation, sprite animation and so on.

The animation framework also -provides concrete implementations of the abstract classes. The concrete implementations -of the CAnimation class are:

CBasicAnimation

This -is a client-side animation class which can also act as a data provider observer -and an animation drawer. It provides a bitmap and a mask on which the animation -is submitted. This class establishes a session with the windows server before -submitting the animation to a particular window.
CSpriteAnimation

This -is a server-side animation class for sprite based animations. The client has -limited control over the animation, as sprites are server-side graphic objects -and are controlled by the server. This class makes use of the windows server -animation API to submit sprite animations. For more information on these APIs, -refer to Using Window -Server (WSERV).
CAnimationGroup

This -class is not an animation class by itself, but is a collection of animations -grouped together. It provides access to an array of animation references and -handles all synchronisation issues among the animations in the group, provided -all the animations are of the same type. For example, if a set of client-side -animations are grouped together, they respond to commands collectively in -synchronisation with each other. If the group includes both sprite and client-side -animations, they will respond to commands collectively in asynchronous mode.

The framework provides the following concrete implementations for -the other two abstract classes, CAnimationDataProvider and CAnimator:

CICLAnimationDataProvider

This -class interprets various data types including animated GIFs using the Image Conversion Library (ICL). -It provides data to the animation class in the form of individual frames using -the CAnimationFrame object which contains a bitmap, a mask, -and frame information.
CBitmapAnimator

This -class can handle fixed sequence of bitmap frames passed by the data provider.

API summary

- - - -Class Name -Description - - - - -

CAnimation

This is an abstract generic class which provides the basic functionality -for all types of animations.

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CAnimator

This is an abstract class, which represents each type of data supported -by the animation framework. This class is implemented as an ECOM plug-in.

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CAnimationDataProvider

This is an abstract class, which takes the animation data and converts -it into a format recognized by the animator.

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CBasicAnimation

This is a concrete implementation class of the CAnimation class. -This class is used for basic client-side animations.

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CSpriteAnimation

This is a concrete implementation class of the CAnimation class. -This class is used for sprite animations.

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Typical uses

Creating a basic animation

The -animation framework can be used to create a basic client-side animation using -the CBasicAnimation class. You can also have your own implementation -for other type of animations. For more information, refer to How -to create a basic animation.

Creating a sprite animation

The -animation framework supports server-side sprite animations using the CSpriteAnimation class. -The procedure to create a sprite animation is the same as that for creating -a basic client-side animation. The only difference between a client-side animation -and a sprite animation is that client-side animations are redrawn by the client -application. Whereas, for sprite animations redraws are handled automatically, -as they run in the window server's high priority thread.