案例代码如下：

import processing.pdf.*;
import java.util.Calendar;
boolean recordPDF = false;

void setup(){
  size(720,720);
  smooth();
  noFill();
  background(255);
}
void draw(){
  if(mousePressed){
    translate(width/2,height/2);
    int circleResolution=(int)map(mouseY,0,height-50,3,11);
    float radius = mouseX-width/2+0.5;
    float angle =TWO_PI/circleResolution;
    strokeWeight(2);
    stroke(0,25);
    beginShape();
    for(int i=0;i<=circleResolution;i++)
    {
      float x=0+cos(angle*i)*radius;
      float y=0+sin(angle*i)*radius;
      vertex(x,y);
    }
    endShape();
   
  }
}
void keyReleased(){
  if(key==DELETE||key==BACKSPACE) background(255);
  if(key=='s'||key=='S')saveFrame(timestamp()+"_##.png");
  if(key=='r'||key=='R'){
    if(recordPDF==false){
      beginRecord(PDF,timestamp()+".pdf");
      println("recording started");
      recordPDF=true;
      smooth();
      noFill();
      background(255);
    }
  }else if(key=='e'||key=='E'){
    if(recordPDF)
    {
      println("recording stopped");
      endRecord();
      recordPDF=false;
      background(255);
    }
  }
}

String timestamp(){
  Calendar now =Calendar.getInstance();
  return String.format("%1$ty%1$tm%1$td_%1$tH%1$tM%1$tS",now);
}
         保存并运行如图1

                                     图1