The DirectX Library is a wrapper library that Lizzy previously had for DirectX8 and updated to use for DirectX9 with use of SlimDX. I updated it myself to be more Object Oriented with use of Events and more logical properties. Here is an idea of what it looks like inside.
The Drawable folder contains interfaces and classes that are used for actually drawing to the screen. LSprite uses the Sprite class from SlimDX to draw, while LVertex uses the TCTVertex class to draw from the SlimDX device.DFont is a custom description class for LFont, with extra information such as outline properties. The LFont is a wrapper class for Font class from SlimDX. It's customized for use with the FontManager and for drawing outlined strings. I'm pretty sure you can figure out what FontManager does.
TCTVertex is a custom TransformedColoredTextured vertex which is used for drawing by LVertex. TransformedColored is the essentially the same one from Microsoft.DirectX but for some reason SlimDX doesn't have it.
LTexture is wrapper class for the Texture class which has a timer feature for the TextureManager to release unused textures.
Finally the DCore class is where everything is held and where all the DirectX stuff happens: TextureManager, FontManager, settings for the DirectX environment, etc.
