Here are the data structures with brief descriptions:

[detail level 12]

Cgd_driver_t	Struct that creates a driver for the display, holding the handle and functions that are private of the display driver. This allows the library to be very flexible and can handles any display
Cgd_font_t	Structure to holds Fonts. The default fonts are defined in GraphicDisplay_Fonts.h. You can create your own fonts. A software that creates this fonts must be searched
Cgd_params_t	Parameters to initialize the Graphic Display Handler
▼Cgd_t	Handler of Graphic Display. Each display must need your own handler. Yes, this library supports multiples displays
Ct_fxn
Ct_intern
Cgd_vertex_t	Structure used to support the creation of polylines. In normal use, this is declared as an array, with X and Y points to build lines, between this lines
Cssd1306_params_t
Cssd1306_t
Cst7920_params_t	Struct to initialize and configure the driver to control the ST7920 peripheral
Cst7920_t	Handler of ST7920. Each display must need your own handler. Yes, this library supports multiples displays