Here are the classes, structs, unions and interfaces with brief descriptions:

[detail level 123]

Application
AudioPort
Circle
Color
ExternalWindow
GraphicsContext
IdleCallback
Image
ImageAboutWindow
ImageBase
ImageButton
Callback
ImageKnob
Callback
ImageSlider
Callback
ImageSwitch
Callback
LeakedObjectDetector
Line
MidiEvent
Mutex
NanoImage
NanoVG
GlyphPosition
Paint
TextRow
NanoWidget
Parameter
ParameterEnumerationValue
ParameterEnumerationValues
ParameterRanges
Plugin
Point
Rectangle
RecursiveMutex
ScopedPointer
ScopeLocker
ScopeTryLocker
ScopeUnlocker
Signal
Size
StandaloneWindow
String
Thread
TimePosition
BarBeatTick
Triangle
UI
VstGuiWidget
Widget
BaseEvent
KeyboardEvent
MotionEvent
MouseEvent
PositionChangedEvent
ResizeEvent
ScrollEvent
SpecialEvent
Window
FileBrowserOptions
Buttons