How to use a boss class?

How to use boss class depends on what you would like to implement.

SDK documentation is the only resource to learn plug-in development in InDesign.

Few things you should understand:

-> InDesign uses its own object model.

This object model is constructed at runtime.

As you know, C++ has an object model, but InDesign although developed in C++ but has its own object model.

InDesign uses an abstraction called boss class.

A boss is a class in the InDesign object model.

-> Objects in InDesign are boss class objects.

This means that a document, page, spread, page item are not C++ objects but boss class objects.

document -> kDocBoss

spread -> kSpreadBoss

etc.

These boss classes have hierachical structure.

Boss class is a kind of InDesign class and not a C++ class.

Plug-ins in InDesign talk to each other via the boss classes.

-> You should have a basic understanding of interface-based programming.

Read basics of Component Object Model (COM).

Programming in InDesign in similar to COM where functionality is accessed via interfaces.

-> Your plug-in will create boss classes, or add features to existing boss classes.

The fr (resource) file is where you define the boss class.

-> You should be familiar with design patterns.

InDesign heavily uses design patterns like observer, command, responder, factory, etc.

-> You have lots of sample code in the SDK which you can refer to.

-> Believe me, InDesign API is very-well documented.

API documentation in products like Photoshop, Illustrator really sucks.

Example:

Suppose I would like to add some custom data to be stored inside each document.

I would add a persistent interface-impl to the kDocBoss.

Here, you add functionality to existing boss.

This would mean that I will create a new interface and impl IDs in the pluginID.h file.

Create a file with the corresponding C++ class.

Register the interface-impl and bind them.

Of course, will add the interface-impl to kDocBoss in the fr file.