一.案例代码如下：
import processing.pdf.*;
import java.util.Calendar;
boolean savePDF = false;
float tileCount =20;
color circleColor = color(0);
int circleAlpha = 180;
int actRandomSeed =0;
void setup(){
size(600,600);
}
void draw(){
if(savePDF)beginRecord(PDF,timestamp()+".pdf");
translate(width/tileCount/2,height/tileCount/2);
background(255);
smooth();
noFill();
randomSeed(actRandomSeed);
stroke(circleColor,circleAlpha);
strokeWeight(mouseY/60);
for(int gridY=0;gridY<tileCount;gridY++){
for(int gridX=0;gridX<tileCount;gridX++){
float posX=width/tileCount*gridX;
float posY =height/tileCount*gridY;
float shiftX=random(-mouseX,mouseX)/20;
float shiftY=random(-mouseX,mouseX)/20;
ellipse(posX+shiftX,posY+shiftY,mouseY/15,mouseY/15);
}
}
if(savePDF)
{savePDF=false;
endRecord();
}
}
void mousePressed(){
actRandomSeed=(int) random(100000);
}
void keyReleased(){
if(key=='s'||key=='S') saveFrame(timestamp()+"_##.png");
if(key=='p'||key=='P') savePDF=true;
}
String timestamp(){
Calendar now=Calendar.getInstance();
return String.format("%1ty%1tm%1td_%1tH%1tM%1tS",now);
}
保存并运行如图1
图1
注意：案例中按下大写P或者小写p保存PDF,如果按下大写S或者小写s可以保存PNG。运行时大家可以多动动鼠标，会发现有趣的变化。