Programming Modes

Basic Mode

In basic mode, you simply type individual lines of commands sequentially into the text editor window, without the added complexity of more complex structures, such as functions or classes. The following code is structured in basic mode and generates a simple red circle, with a black stroke on a yellow background:
size(200, 200);
background(255, 255, 0);
stroke(0);
fill(255, 0, 0);
int x = 100;
int y = 100;
int w = 140;
int h = 140;
ellipse(x, y, w, h);




Continuous mode

In continuous mode, you build upon basic mode, with the edition of code structures called functions and classes. Functions are the main building blocks used in procedural programming, and are simply groupings of lines of code that execute only when they are explicitly called. Classes are more complicated structures than functions, and are utilized in OOP. In basic mode, code is executed linearly (line by line). Functions and classes, on the other hand, allow code to be executed nonlinearly. In continuous mode, two basic Processing functions are provided:
void setup(){
}
void draw(){
}
The setup() function is called only once, at the start of the program. This is the place where you normally initialize variables that will be used later in the program. Adding the setup() function to your sketch allows you to add your own additional custom functions and classes.

The draw() function adds animation capabilities to your sketch and has a built-in loop, more accurately called a thread or timer. By default, adding the draw() function to your sketch causes any code between the curly braces of this structure to continuously execute.



Java mode

This mode allows you to work in pure Java, from directly within the Processing text editor. Java mode is extremely flexible, giving you access to the entire Java API.