wrr · May 14, 2019 00:27
diff --git a/index.html b/index.html
 <!DOCTYPE html>
 <!-- By Jan Wrobel. See it working at:
     http://mixedbit.org/blog/2013/02/10/random_walk_illustrated_with_d3.html
 -->

 <html>

  <head>
    <meta http-equiv="Content-Type" content="text/html;charset=utf-8">
    <title>Random walk</title>
    <script type="text/javascript" src="http://d3js.org/d3.v3.min.js"></script>
    <script type="text/javascript" src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
    <style type="text/css">

 body {
  background: #222;
 }
     </style>
 </head>
 <body>
  <button type="button" onclick="faster();">Faster!</button>
 <script type="text/javascript">

 function init_array(size, init_v) {
  var result = [];
  for (i = 0; i < size; i += 1) {
    result.push(init_v);
  }
  return result;
 }

 var GRID = 5,
 WALK_H = 280,
 WALK_W = 2 * WALK_H,
 PLOT_H = 1.5 * WALK_H / 2,
 POINT_R = 4,
 delay = 100,
 result_cnt = init_array(WALK_W / GRID, 0),
 svg = d3.select("body").append("svg:svg")
  .attr("width", WALK_W)
  .attr("height", WALK_H + PLOT_H + POINT_R),
 // From
 // https://github.com/mbostock/d3/blob/master/lib/colorbrewer/colorbrewer.js
 // colorbrewer.Oranges[9]
 // See https://github.com/mbostock/d3/blob/master/lib/colorbrewer/LICENSE
 PALETE = ["rgb(255,245,235)", "rgb(254,230,206)", "rgb(253,208,162)",
          "rgb(253,174,107)", "rgb(253,141,60)", "rgb(241,105,19)",
          "rgb(217,72,1)","rgb(166,54,3)", "rgb(127,39,4)"].reverse();

 $('button').attr('disabled', false);
 walk(WALK_W / 2, 0);

 function faster() {
  if (delay > 20) {
    delay -= 20;
  } else {
    delay = 0;
    $('button').attr('disabled', true);
  }
 }
 function append_result(final_x) {
  var result_idx = final_x / GRID;
  svg.append("svg:circle")
    .attr("cx", final_x)
    .attr("cy", WALK_H + POINT_R)
    .attr("r", POINT_R)
    .style("fill", "aliceblue")
    //.style("opacity", 0.85)
    .transition()
    // Move the result point to the bottom of the plot.
    .attr("cy", WALK_H + PLOT_H - 2 * POINT_R * result_cnt[result_idx] )
    .duration(3000);
  result_cnt[result_idx] += 1;
 }

 function walk(x, y) {
  var x_end, y_end = y + GRID;
  if (Math.random() < 0.5) {
    x_end = x + GRID;
  } else {
    x_end = x - GRID;
  }
  line = svg.select('line[x1="' + x + '"][x2="' + x_end + '"]'+
                    '[y1="' + y + '"][y2="' + y_end + '"]');
  if (line.empty()) {
    // Create a new line segment
    svg.append("svg:line")
      .attr("x1", x)
      .attr("y1", y)
      .attr("x2", x_end)
      .attr("y2", y_end)
      .style("stroke", PALETE[0])
      .style("stroke-width", 2)
      .datum(0);
  } else {
    // or alter color of an existing line.
    var color_idx = Math.min(line.datum() + 1, PALETE.length - 1);
    line.style('stroke', PALETE[color_idx])
      .datum(color_idx)
  }

  if (y_end >= WALK_H) {
    // End reached.
    append_result(x_end);
    x_end = WALK_W / 2;
    y_end = 0;
  }
  window.setTimeout(function() {
    walk(x_end, y_end);
  }, delay);
 }

 </script>
 </body>
 </html>
	<!DOCTYPE html>
	<!-- By Jan Wrobel. See it working at:
	http://mixedbit.org/blog/2013/02/10/random_walk_illustrated_with_d3.html
	-->

	<html>

	<head>
	<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
	<title>Random walk</title>
	<script type="text/javascript" src="http://d3js.org/d3.v3.min.js"></script>
	<script type="text/javascript" src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
	<style type="text/css">

	body {
	background: #222;
	}
	</style>
	</head>
	<body>
	<button type="button" onclick="faster();">Faster!</button>
	<script type="text/javascript">

	function init_array(size, init_v) {
	var result = [];
	for (i = 0; i < size; i += 1) {
	result.push(init_v);
	}
	return result;
	}

	var GRID = 5,
	WALK_H = 280,
	WALK_W = 2 * WALK_H,
	PLOT_H = 1.5 * WALK_H / 2,
	POINT_R = 4,
	delay = 100,
	result_cnt = init_array(WALK_W / GRID, 0),
	svg = d3.select("body").append("svg:svg")
	.attr("width", WALK_W)
	.attr("height", WALK_H + PLOT_H + POINT_R),
	// From
	// https://github.com/mbostock/d3/blob/master/lib/colorbrewer/colorbrewer.js
	// colorbrewer.Oranges[9]
	// See https://github.com/mbostock/d3/blob/master/lib/colorbrewer/LICENSE
	PALETE = ["rgb(255,245,235)", "rgb(254,230,206)", "rgb(253,208,162)",
	"rgb(253,174,107)", "rgb(253,141,60)", "rgb(241,105,19)",
	"rgb(217,72,1)","rgb(166,54,3)", "rgb(127,39,4)"].reverse();

	$('button').attr('disabled', false);
	walk(WALK_W / 2, 0);

	function faster() {
	if (delay > 20) {
	delay -= 20;
	} else {
	delay = 0;
	$('button').attr('disabled', true);
	}
	}
	function append_result(final_x) {
	var result_idx = final_x / GRID;
	svg.append("svg:circle")
	.attr("cx", final_x)
	.attr("cy", WALK_H + POINT_R)
	.attr("r", POINT_R)
	.style("fill", "aliceblue")
	//.style("opacity", 0.85)
	.transition()
	// Move the result point to the bottom of the plot.
	.attr("cy", WALK_H + PLOT_H - 2 * POINT_R * result_cnt[result_idx] )
	.duration(3000);
	result_cnt[result_idx] += 1;
	}

	function walk(x, y) {
	var x_end, y_end = y + GRID;
	if (Math.random() < 0.5) {
	x_end = x + GRID;
	} else {
	x_end = x - GRID;
	}
	line = svg.select('line[x1="' + x + '"][x2="' + x_end + '"]'+
	'[y1="' + y + '"][y2="' + y_end + '"]');
	if (line.empty()) {
	// Create a new line segment
	svg.append("svg:line")
	.attr("x1", x)
	.attr("y1", y)
	.attr("x2", x_end)
	.attr("y2", y_end)
	.style("stroke", PALETE[0])
	.style("stroke-width", 2)
	.datum(0);
	} else {
	// or alter color of an existing line.
	var color_idx = Math.min(line.datum() + 1, PALETE.length - 1);
	line.style('stroke', PALETE[color_idx])
	.datum(color_idx)
	}

	if (y_end >= WALK_H) {
	// End reached.
	append_result(x_end);
	x_end = WALK_W / 2;
	y_end = 0;
	}
	window.setTimeout(function() {
	walk(x_end, y_end);
	}, delay);
	}

	</script>
	</body>
	</html>