QuickTime 4 Reference

Structure of the Framework

The effect framework is one approach to writing effects components. It has been designed to provide most of the basic code required to implement an effect component, leaving the implementation of the effect algorithm to you. It should be possible to write most effects using the framework, though you may need to adapt the framework code for more complex effect components.

The framework implements the required component functions for an effect. The main body of the framework is the Effect.c file, which contains the source code for the framework and an implementation of the dimmer effect. This file is made up of four main parts:

The global data structures used by the framework. You will need to update some of the data structures to reflect the capabilities of the effect you are implementing.
The dispatcher is the entry point to your component. Because all effects components have the same set of component functions, you should not need to alter the dispatcher.
The internal functions are the set of functions that actually execute your effect. This is where most of your own code will be added.
The component functions are the standard functions called by the dispatcher. These functions call the internal functions to actually execute the effect. For most effects, you won't need to change much code in this section.

Naming Conventions

All the function and data structure names in the framework are arbitrary. The names have been chosen to reflect their purpose, but you are free to change the names, as long as they remain internally consistent.

If you choose to change the names of the component functions, you will have to change the CALLCOMPONENT_BASENAME #define in Effect.c . This defines the root of the name used for component functions. For example, if CALLCOMPONENT_BASENAME is set to SlideEffect , then the Open component function must be called SlideEffectOpen , the Close component function must be called SlideEffectClose , and so forth.

Apple recommends that you do not change the names used in the framework.