Is it possible to change color of one pixel inside rectangle created with KineticJS?

This is my code:

var Editor = {
    layer: new Kinetic.Layer(),
    map: null,
    init: function () {
        var stage = new Kinetic.Stage({
            container: 'board',
            width: 800,
            height: 800
        })
        this.map = new Kinetic.Shape({
            sceneFunc: function(context) {
                context.beginPath();
                context.moveTo(0, 0);
                context.lineTo(mapWidth, 0);
                context.lineTo(mapWidth, mapHeight);
                context.lineTo(0, mapHeight);
                context.closePath();
                context.fillStrokeShape(this);
            },
            x: 0,
            y: 0,
            fill: 'green',
            draggable: true
        })

        this.layer.add(this.map)
        stage.add(this.layer)
    }
}

I want to change the colors of the pixels in the rectangle. Colors of pixels will be generated by the "diamond-square" algorithm. Is it possible to change the colors of individual pixels? If so, how can I do this?

Solution

[ Changed answer ]

Use an offscreen html canvas to overlay the pixels in your "diamond-square" algorithm.

Demo: http://jsfiddle.net/m1erickson/6mDSm/

enter image description here

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Prototype</title>
    <script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
    <script src="http://d3lp1msu2r81bx.cloudfront.net/kjs/js/lib/kinetic-v5.0.1.min.js"></script>
<style>
body{padding:20px;}
#container{
  border:solid 1px #ccc;
  margin-top: 10px;
  width:350px;
  height:350px;
}
</style>        
<script>
$(function(){


    var stage = new Kinetic.Stage({
        container: 'container',
        width: 350,
        height: 350
    });
    var layer = new Kinetic.Layer();
    stage.add(layer);

    var mapWidth=50;
    var mapHeight=75;

    // use an offscreen canvas as a pixel-map overlaying the green map
    var pixelCanvas=document.createElement("canvas");
    var ctx=pixelCanvas.getContext("2d");
    pixelCanvas.width=mapWidth;
    pixelCanvas.height=mapHeight;
    pixelCanvas.pixels=[]
    pixelCanvas.setPixel=function(x,y,color){
        ctx.fillStyle=color;
        ctx.fillRect(x,y,1,1);
    };

    // create a group
    // that holds the green map background and pixel-map overlay
    var mapGroup=new Kinetic.Group({
        x:30,
        y:30,
        width:mapWidth,
        height:mapHeight,
        draggable:true
    });
    layer.add(mapGroup);

    // the green background
    var map=new Kinetic.Rect({
        x:0,
        y:0,
        width:mapWidth,
        height:mapHeight,
        fill:"green"
    });
    mapGroup.add(map);

    // an image overlay that 
    // gets "live-updates" from an offscreen canvas

    var pixels=new Kinetic.Image({
        x:0,
        y:0,
        image:pixelCanvas
    });
    mapGroup.add(pixels);

    layer.draw();

    // testing

    var y=15;
    $("#add").click(function(){
        for(var i=0;i<5;i++){
            pixelCanvas.setPixel(15,y,"red");
            pixelCanvas.setPixel(25,y,"gold");
            pixelCanvas.setPixel(35,y++,"blue");
        }
        pixels.draw();
    });


}); // end $(function(){});

</script>       
</head>
<body>
    <button id="add">Add test Pixels</button>
    <div id="container"></div>
</body>
</html>

Note: my previous answer using Kinetic.Shape was leaving an undesirable "ghost"