I made a program which saves the output as a pdf with transparency but it runs very slowly and it wont work as an applet.
Also it hangs if i try to reset tha PGraphics background (ive commented the line below)
Am i doing anything wrong, or is there another way?

import processing.pdf.*;

PGraphics pgpdf;
....

void setup() {  
 ....
 pgpdf = createGraphics(mywidth, myheight,PDF, "pattern.pdf");

 ....
 drawWithLine();
}

....

void update(int x, int y)
{
 
 ...
 if(mousePressed) {
   if(saveBtn.pressed() && !saving) {
     println("going to save");
     saveFile();
     
   } else if (redrawBtn.pressed()) {
     println("redrawing");
     pgpdf = createGraphics(mywidth, myheight,PDF, "pattern.pdf");
     drawWithLine();
   }
 }
}


void saveFile() {
 saving = true;
 pgpdf.dispose();
 println("File Written");
 saving = false;
}

void drawWithLine() {
 background(255);
 strokeWeight(1);
 stroke(200,100,23);
 
 // pgpdf.background(0,0) this results in nullpointexcept.
 pgpdf.beginDraw();  
 pgpdf.strokeWeight(1);
 pgpdf.stroke(200,100,23);

 for(int i=0; i<density; i++) {
   
   //lets create one with x 0
   int rx1 = 0;
   int rx2 = mywidth;
   int ry1 = int(random(myheight));
   int ry2 = int(random(myheight));
   line(rx1, ry1, rx2, ry2);
   pgpdf.line(rx1, ry1, rx2, ry2);    
   //and now one with y 0
   rx1 = int(random(mywidth));
   rx2 = int(random(mywidth));
   ry1 = 0;
   ry2 = myheight;
   line(rx1, ry1, rx2, ry2);
   pgpdf.line(rx1, ry1, rx2, ry2);
 }
 
 
pgpdf.endDraw();
 
}

thanx...