General

Look at Writeable Variables' Home first.

These variable say to the library how things should be drawn.

globalColor [Color]

It holds the color that is going to be used for all shapes and for creating objects when some arguments aren't specified.
Recommended to also look at ComputerCraft's Colors API.

globalTextColor [Color]

It holds the color that is going to be used for all texts.
Recommended to also look at ComputerCraft's Colors API.

globalBackgroundTextColor [Color]

It holds the color that is going to be used for all texts' backgrounds.
Recommended to also look at ComputerCraft's Colors API.

globalRectangleType [RectangleType]

It holds the type of rectangle that should be drawn.
Recommended to also look at APLib's rectangleTypes.