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                <canvas id="matisse" />


                * { margin: 0; padding: 0; }
body {  overflow: hidden; }
canvas { background: #fffff3; }


  // initialize drawing status
  var shape = {
    status: false,
    color: 'rgba(34,121,192,.85)',
    shadowColor: 'rgba(34,121,192,1)',
    startX: 0,
    startY: 0,
    coords: []
  // get the canvas, set to full width
  var canvas = $('canvas')[0];
  canvas.width = $(document).width();
  canvas.height = $(document).height();
  // get the context
  var ctx = canvas.getContext('2d');
  // set fill, stroke, and shadow styles
  ctx.fillStyle = shape.color;
  ctx.strokeStyle = shape.color;
  ctx.lineWidth = 1;
  ctx.shadowOffsetX = 0;
  ctx.shadowOffsetY = 0; 
  ctx.shadowBlur = 1;
  ctx.shadowColor = shape.shadowColor;
  // set the click event to start drawing
    // 1. get the x,y just clicked
    var currentX = e.clientX;
    var currentY = e.clientY;
    // 2. if shape not drawn yet, set init values and draw start
    if ( !shape.status ) {
      shape.status = true;
      shape.startX = currentX;
      shape.startY = currentY;
      ctx.moveTo(currentX, currentY);
      ctx.fillRect(currentX, currentY, 2, 2);
    // 3. else, we can draw a line of our shape...
    else {
      // 3.a get the previous x,y clicked
      var lastX = shape.coords[shape.coords.length - 1][0];
      var lastY = shape.coords[shape.coords.length - 1][1];
      // 3.b draw the line
      ctx.lineTo(currentX, currentY);
      // 3.c if this is within 10px of the initial coordinate and there are less than three points in the shape so far, close it and fill the shape
      if ( Math.abs( shape.startX - currentX ) < 11 && Math.abs( shape.startY - currentY ) < 11 && shape.coords.length > 2 ) {
        ctx.lineTo( shape.startX, shape.startY);
        // reset shape and wash your hands of it
        shape.status = false; 
        shape.coords = [];
    // 4. add this coordinate to our array