Reference. Processing was designed to be a flexible software sketchbook.
Structure
Environment
Data
Primitive
Composite
Conversion
String Functions
Array Functions
Control
Relational Operators
Iteration
Conditionals
Logical Operators
Shape
2D Primitives
Curves
3D Primitives
Attributes
Vertex
Loading & Displaying
Input
Mouse
Keyboard
Files
Time & Date
Output
Text Area
Image
Files
Transform
Lights, Camera
Lights
Camera
Coordinates
Material Properties
Color
Setting
Creating & Reading
Image
Loading & Displaying
Textures
Pixels
Rendering
Shaders
Typography
Loading & Displaying
Attributes
Metrics
Math
Operators
Bitwise Operators
Calculation
Trigonometry
Random
Constants