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tomshanley

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Animate line and points

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forked from tomshanley's block: Animate line and points

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8"/>
  
  <style>
    path {
      stroke-width: 2px;
      fill: none;
    }
  </style>

</head>
<body>
  
  <p>Click the chart to start the animation.</p>
  
  <div id="line"></div>
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <script type="text/javascript">
    
    console.clear()    
    
    var w = 700;
    var h = 300; 
    var m = 40;
    
    var max = 10

var svg = d3.select("#line")
      .append("svg")
      .attr("width", w + m + m)
      .attr("height", h + m + m)
    
    var chart = svg.append("g")
    	.attr("transform", "translate(" + m + "," + m + ")")

var data = d3.range(max+1)
    .map(function(){
      return Math.random() * max
    })

var x = d3.scaleLinear()
    .domain([0, max])
    .range([0, w]);
    
    var y = d3.scaleLinear()
    .domain([0, max])
    .range([h, 0]);
    
    var line = d3.line()
      .x(function(d,i) {return x(i);})
      .y(function(d) {return y(d);})
    	.curve(d3.curveCardinal)
    
    var clipPath = chart.append("clipPath")
    	.attr("id", "clip")
    	.append("rect")
    	.attr("id", "clip-rect")
    	.attr("width", 0)
    	.attr("height", h)
    
    var bkdPath = chart.append("path")
      .attr("d", line(data))
      .style("stroke", "lightgrey")
    
    var path = chart.append("path")
      .attr("d", line(data))
      .style("stroke", "orange")
    	.style("stroke-width", "5px")
    	.attr("clip-path", "url(#clip)")
    
    var bkdCircle = chart.selectAll(".bkd-circle")
      .data(data)
    	.enter()
    	.append("g")
    	.attr("transform", function(d, i){
        return "translate(" + x(i) + "," + y(d) + ")"
      })
    	.attr("class", "bkd-circle")
			.append("circle")
    	.attr("r", 5)
    	.style("stroke", "lightgrey")
    	.style("fill", "white")
    
    var dataPoint = chart.selectAll('.data-point')
    	.data(data)
    	.enter()
    	.append("g")
    	.attr("transform", function(d, i){
        return "translate(" + x(i) + "," + y(d) + ")"
      })
    	.attr("class", "data-point")
    	.attr("id", (d, i) => "data-point-" + i)
    	.style("opacity", 0)
    
    dataPoint.append("circle")
    	.attr("r", 5)
    
    dataPoint.append("text")
    	.text((d, i) => i + ", " + round2dp(d) )
    	.attr("dy", 18)
    
    let pointArray = []    
    let sampleRate = 100
  	let sampleWidth = w / sampleRate
    let currentLength = 0
    let node = path.node()
    let pathLength = node.getTotalLength()
    let s = 0
    let dur = 10000
    
   
    
    for (var j = 0; j<pathLength; j++){
      let point = node.getPointAtLength(j)
      console.log(point)
      if (point.x >= (sampleWidth * s)) {
        console.log("here")
        pointArray.push(point)
        s = s + 1
      }
    }
 
    
    
    chart.selectAll(".markers")
    	.data(pointArray)
    	.enter()
    	.append("circle")
    	.attr("cx", d => d.x)
    	.attr("cy", d => d.y)
    	.attr("r", 2)
    	.style("fill", "red")
    
    console.log(pointArray)
    
    
    let head = chart.append("circle")
    	.datum(pointArray)
    	.attr("cx", d => d[0].x)
    	.attr("cy", d => d[0].y)
    	.attr("r", 15)
    	.style("fill", "green")
    	.attr("id", "head")
    
    
    let tIndex = 0
    
    function transitionCircle(){
      tIndex =  tIndex + 1
      if (tIndex > (pointArray.length - 1)) {
        
      } else {
      	head.transition()
          .duration(dur / (sampleRate + 1))
          .ease(d3.easeLinear)
          .attr("cx", d => d[tIndex].x)
          .attr("cy", d => d[tIndex].y)
          .on("end", transitionCircle)  
      }
      
    }
    
    transitionCircle()
    
   d3.select('#clip-rect')      
        .transition()
        .duration(dur)
      	.ease(d3.easeLinear)
        .attr("width", w)
    
    
    function round2dp(n) {
      return Number.parseFloat(n).toFixed(2);
    }
    
    
  </script>
</body>
</html>

https://d3js.org/d3.v4.min.js