harrytruong/README.md

## README.md

      
    Raw
  

              README.md
            
          
    Marker animation along SVG "path" element with D3.js: animating "path" and marker movement synchronously.

  
## index.html
<!DOCTYPE html>
<html lang="en">
<meta charset="utf-8">
<head>
  <title>SVG path animation</title>
  <link href="style.css" rel="stylesheet">
  <script src="http://d3js.org/d3.v3.min.js"></script>
  <script src="http://d3js.org/queue.v1.min.js"></script>
</head>
<body>
  <!-- start -->
  <div id="pathAnimation">
    <script src="pathFollowAnimation.js"></script>
  </div>
  <!-- end -->
</body>
</html>

## pathFollowAnimation.js
queue()
.defer(d3.xml, "wiggle.svg", "image/svg+xml")
.await(ready);

function ready(error, xml) {

  //Adding our svg file to HTML document
  var importedNode = document.importNode(xml.documentElement, true);
  d3.select("#pathAnimation").node().appendChild(importedNode);

  var svg = d3.select("svg");

  var path = svg.select("path#wiggle").call(transition);
  var startPoint = pathStartPoint(path);

  var marker = svg.append("circle");
  marker.attr("r", 7)
    .attr("id", "marker")
    .attr("transform", "translate(" + startPoint + ")");

  //Get path start point for placing marker
  function pathStartPoint(path) {
    var d = path.attr("d"),
    dsplitted = d.split(" ");
    return dsplitted[1];
  }

  function transition(path) {
    path.transition()
        .duration(7500)
        .attrTween("stroke-dasharray", tweenDash)
        .each("end", function() { /*d3.select(this).call(transition);*/ });// infinite loop
  }

  function tweenDash() {
    var l = path.node().getTotalLength();
    var i = d3.interpolateString("0," + l, l + "," + l); // interpolation of stroke-dasharray style attr
    return function(t) {
      var marker = d3.select("#marker");
      var p = path.node().getPointAtLength(t * l);
      marker.attr("transform", "translate(" + p.x + "," + p.y + ")");//move marker
      return i(t);
    }
  }
}

## style.css
path {
  fill: none;
  stroke: #000;
  stroke-width: 1px;
}

circle {
  fill: red;
}

## wiggle.svg

      
Display the source blob

    
Display the rendered blob

    
    Raw
  

              wiggle.svg
            
          
      Sorry, something went wrong. Reload?
      Sorry, we cannot display this file.
      Sorry, this file is invalid so it cannot be displayed.
      
          Viewer requires iframe.
	<!DOCTYPE html>
	<html lang="en">
	<meta charset="utf-8">
	<head>
	<title>SVG path animation</title>
	<link href="style.css" rel="stylesheet">
	<script src="http://d3js.org/d3.v3.min.js"></script>
	<script src="http://d3js.org/queue.v1.min.js"></script>
	</head>
	<body>
	<!-- start -->
	<div id="pathAnimation">
	<script src="pathFollowAnimation.js"></script>
	</div>
	<!-- end -->
	</body>
	</html>
	queue()
	.defer(d3.xml, "wiggle.svg", "image/svg+xml")
	.await(ready);

	function ready(error, xml) {

	//Adding our svg file to HTML document
	var importedNode = document.importNode(xml.documentElement, true);
	d3.select("#pathAnimation").node().appendChild(importedNode);

	var svg = d3.select("svg");

	var path = svg.select("path#wiggle").call(transition);
	var startPoint = pathStartPoint(path);

	var marker = svg.append("circle");
	marker.attr("r", 7)
	.attr("id", "marker")
	.attr("transform", "translate(" + startPoint + ")");

	//Get path start point for placing marker
	function pathStartPoint(path) {
	var d = path.attr("d"),
	dsplitted = d.split(" ");
	return dsplitted[1];
	}

	function transition(path) {
	path.transition()
	.duration(7500)
	.attrTween("stroke-dasharray", tweenDash)
	.each("end", function() { /d3.select(this).call(transition);/ });// infinite loop
	}

	function tweenDash() {
	var l = path.node().getTotalLength();
	var i = d3.interpolateString("0," + l, l + "," + l); // interpolation of stroke-dasharray style attr
	return function(t) {
	var marker = d3.select("#marker");
	var p = path.node().getPointAtLength(t * l);
	marker.attr("transform", "translate(" + p.x + "," + p.y + ")");//move marker
	return i(t);
	}
	}
	}
	path {
	fill: none;
	stroke: #000;
	stroke-width: 1px;
	}

	circle {
	fill: red;
	}