Old school D3 from simpler times

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tomshanley

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Animate line and points

Built with blockbuilder.org

<!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")
    	.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 = 10
  	let sampleWidth = w / sampleRate
    let currentLength = 0
    let node = path.node()
    let pathLength = node.getTotalLength()
   
    for (var i = 0; i<sampleRate; i++) {
      
      console.log(i * sampleWidth)
      
      for (var j = 0; j<1000; j++){
        let point = node.getPointAtLength(currentLength + j)
        console.log(point)
        if (point.x >= (sampleWidth * i)) {
          console.log("here")
          pointArray.push(point)
          currentLength = point.x
          break
        }
      }
    }
    
    chart.selectAll(".markers")
    	.data(pointArray)
    	.enter()
    	.append("circle")
    	.attr("cx", d => d.x)
    	.attr("cy", d => d.y)
    	.attr("r", 5)
    	.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", 5)
    	.style("fill", "green")
    	.attr("id", "head")
    
    /*    
    var show = false
    
    
    
    svg.on("click", function(){
    
    	head.transition()
        .duration(10000)
      	.ease(d3.easeLinear)
        .tween("attr.cx", function() {

return function(t) {
          
          
            }
            
            })
    
      d3.select('#clip-rect')      
        .transition()
        .duration(10000)
      	.ease(d3.easeLinear)
        .attr("width", function(d){
        	let n = w
        	if (show) {
            show = false
            n = 0
          } else {
            show = true
          }
        	return n
      	})
      	.tween("attr.fill", function() {

return function(t) {
            
            let kx = show ? 
                Math.floor(t * max) : 
            		Math.ceil((1-t) * max)
                        
            let id = "#data-point-" + kx
            
            d3.selectAll(".data-point")
            	.style("opacity", 0)

d3.select(id)
            	.style("opacity", 1)
          };
        
        });
    })
    
    */
    
    function round2dp(n) {
      return Number.parseFloat(n).toFixed(2);
    }

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

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