fill.js

var r = new Rune({
  container: "#canvas",
  width: 800,
  height: 600
});

var myPoly = r.polygon(400, 200)
  .lineTo(0, 0)
  .lineTo(200, 50)
  .lineTo(250, 60)
  .lineTo(200, 150)
  .lineTo(-200, 150)
  .lineTo(-250, 60)
  .lineTo(-200, 50)

// shifmanns code
var circles = [];
for(var x = 0; x < r.width; x += 20) {
  for(var y = 0; y < r.height; y += 20) {
    var myCircle = r.circle(x, y, 10)
    circles.push(myCircle)
  }
}

for(var i = 0; i < circles.length; i++) {
  if(myPoly.contains(circles[i].state.x, circles[i].state.y)) {
    circles[i].fill(0, 255, 0)
  } else {
    circles[i].fill(0, 0, 255)
  }
}


myPoly.removeParent();


r.draw();