Introduction

In this sketch we will be handing the drawing responsibilities entirely over to the computer.

We are also adding functionality to Processing by importing a library into our sketch.

Sketch #4

We will start at the sketch menu at the top of the screen and select Import Library:

Select PDF Export:

Processing will insert a line at the beginning of your sketch:

import processing.pdf*;

In this sketch we are going to use Perlin noise to inform the random movement of the pen on the screen. We are going to use float, which in Processing is a container (variable) in which you can put numbers and pull them up later.

float perlinPosition = 0;

float perlinSpeed = 0.01;

void setup() {

size(600,600);

background(255);

beginRecord(PDF, "pdf/wheel.pdf"); //begin the PDF renderer record

}

This sketch takes a unique approach to drawing: instead of making us figure out the rotation, we are going to make the "paper" rotate:

void draw() {

translate(width/2, height/2); //moves the point of origin to middle of screen

rotate(frameCount * 0.01); // turn the drawing surface, makes it so you don't have to use sine and cosine aka trigonometry

float armLength = noise(perlinPosition) *200; //define how long the line is drawn by using perlin noise

perlinPosition = perlinPosition + perlinSpeed;

stroke(0,50); //stroke is black then gray

line(0 , 0 , armLength, 0);

ellipse( armLength, 0, 5, 5);

}