GOL Objects

All the GOL objects that will be shown in the display have a corresponding data structure that keeps and maintains its parameters. 

Each object type has a set of functions that enables the user to change the state of the object. The Microchip graphics library supports the following set of GOL objects.

Each GOL object type uses a style scheme. The style scheme defines the font and color settings. User can create new style schemes and assign it to objects. Multiple style schemes can be used for different objects. 

To efficiently manage the different objects the first 9 fields of the structure for each object are defined the same. Collectively they are referred to as the object header structure (OBJ_HEADER). Defining the OBJ_HEADER enables the common APIs to manage the objects of different types in the same manner. 

The GOL operation is centered on two major processes. First is the rendering process and second is the messaging process. These processes make use of linked list objects. The field pNxtObj in OBJ_HEADER makes this possible. To manage the list a global pointer _pGolObjects is utilized. It defines the current active linked list. Newly created objects are automatically added to the end of this list. The active linked list is the list that the messaging and rendering operation parses to evaluate if the messages received affect the objects and if objects need to be redrawn. 

The use of the _pGolObjects pointer also provides a way to easily manage objects. In applications where multiple pages are displayed on the screen, objects can be grouped according to pages. The pointer can be manipulated to switch from one page to another depending on the page currently shown on the screen.

Implementation of Multi-Page Objects

User can remove an object from a list by pointer manipulation. Objects that are removed from the list are not accessible by the rendering and messaging processes.