I have this really easy sketching thingy that I'm using with processing.js. The problem is, when you use this on a webpage and people move their mouse too fast (outside the canvas) the lines get all weird and jumpy. How can I prevent this?

1. void setup() {
    size(320, 320);
    background(255);
    noStroke();
    
   }
   
   void draw() {
     int strokeValue = $("#sliderR").slider("value");
   
   
     String picker = $(".simpleColorDisplay").data('backgroundcolor');
     color c = unhex("FF"+picker);
     stroke(c);
     
     strokeWeight(strokeValue);
     smooth();
   
       if (mousePressed  && (mouseButton == LEFT)) {
         line(pmouseX, pmouseY, mouseX, mouseY);
       }
   }
   
   

I am trying to isolate/copy the pixels from a blob and thought the pixels-field would be the way to do it: http://ubaa.net/shared/processing/opencv/blob.html
But so far, i get exactly 0 from this. Has anybody used this field succesfully? Or does anybody know another way to copy the pixels from a blob?     

I would like to use it as a sort of glorified magic wand tool.