Here are the classes, structs, unions and interfaces with brief descriptions:
| Gosu::Bitmap | Rectangular area of pixels, each represented by a Color value |
| Gosu::Buffer | Piece of memory with the Resource interface |
| Gosu::Button | Very lightweight class that identifies a button (keyboard, mouse or other device) |
| Gosu::Color | Represents an RGBA color value with 8 bits for each channel |
| Gosu::CommSocket | Wraps a TCP socket that is used for one part of bi-directional communication |
| Gosu::File | File with the Resource interface |
| Gosu::Font | A font can be used to draw text on a Graphics object very flexibly |
| Gosu::GLTexInfo | Contains information about the underlying OpenGL texture and the u/v space used for image data |
| Gosu::Graphics | Serves as the target of all drawing and provides primitive drawing functionality |
| Gosu::Image | Provides functionality for drawing rectangular images |
| Gosu::ImageData | Abstract base class for drawable images |
| Gosu::Input | Manages initialization and shutdown of the input system |
| Gosu::ListenerSocket | Wraps a TCP socket that waits on a specific port and can create CommSocket instances via its onConnection event |
| Gosu::MessageSocket | Wraps an UDP socket |
| Gosu::Reader | Utility class that points to a specific position in a resource and offers an interface for sequential reading |
| Gosu::Resource | Base class for resources |
| Gosu::Sample | A sample is a short sound that is completely loaded in memory, can be played multiple times at once and offers very flexible playback parameters |
| Gosu::SampleInstance | An instance of a Sample playing |
| Gosu::Song | Songs are less flexible than samples in that they can only be played one at a time and without panning or speed parameters |
| Gosu::TextInput | TextInput instances are invisible objects that build a text string from input, using the current operating system's keyboard layout |
| Gosu::Touch | Struct that saves information about a touch on the surface of a multi- touch device |
| Gosu::Window | Convenient all-in-one class that serves as the foundation of a standard Gosu application |
| Gosu::Writer | Utility class that points to a specific position in a resource and offers an interface for sequential writing |