Basic Steps to Subtype a Graphic Object

Foundation > Graphic Objects > Creating a New Graphic Object Class > Basic Steps to Subtype a Graphic Object

To create derived classes of the IlvGraphic class, you:

1. Create a header file that declares the new class and the necessary overloaded member functions. Not every member function needs to be overloaded.

2. Add the DeclareTypeInfo(); statement in the class definition.

This creates the necessary fields and member function declarations for input/output operations and class hierarchy information.

3. Add the DeclareIOConstructors(ShadowEllipse); statement in the class declaration, which declares two additional constructors:

The following constructor initializes a new ShadowEllipse graphic object, which is a copy of source:

ShadowEllipse(const ShadowEllipse& source);

The following constructor initializes a new ShadowEllipse graphic object from the parameters read in the inputfile:

ShadowEllipse(IlvInputFile& inputfile,

IlvPalette* palette = 0);

4. Create an implementation file (usually class.cpp) to implement the member functions that you need. Outside the body of a function, add a call to the two following macros:

IlvRegisterClass, which updates the class hierarchy information.

IlvPredefinedIOMembers, which is used to define the member functions copy and read.

Version 6.1