Understanding-Zoom/zoom_step_02.html at master · larsvers/Understanding-Zoom · GitHub

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<!DOCTYPE html>

<html lang="en">

<head>

<title>Planets</title>
<meta charset="utf-8">

<script src="//d3js.org/d3.v4.js"></script>

<style type="text/css">


	/* HTML elements */
	/* ============= */

	/* Base elements */

	body {
		font-family: Avenir, sans-serif;
		font-size: 0.75rem;
		margin: 0;
	}

	#headline {
	  position: absolute;
	  top: 0;
	  left: 0;
	  width: 100%;
		text-align: center;
		color: #555;
	}

	#pink {
		border-bottom: 2px solid deeppink;
		padding-bottom: 0.25rem;
	}

	/* Links */

	a {
	  color: #555;
	  transition: color 200ms;
	}

	a:link {
		text-decoration: none;
	}
	a:visited {
		color: #555;
	}
	a:hover {
		color: deeppink;
	}
	a:active {
		color: #555;
	}


	/* SVG elements */
	/* ============ */

	svg {
	  border: 1px solid #ccc;
	}

	/* Axes */

	.tick text {
	  font-family: Avenir, sans-serif;
	  fill: #555;
	  font-size: 0.75rem;
	}

	.tick line, .lines {
	  stroke: #555;
	  stroke-width: 0.5;
	  shape-rendering: crispEdges;
	}

	path.domain {
	  display: none;
	}

	/* Chart */

	circle {
		fill: white;
		stroke: deeppink;
		stroke-width: 4px;
	}

	.label {
	  fill: #777;
	}


</style>

</head>

<body>

<h1 id="headline">Measuring our planets'
	<span id="pink">
		<a href="https://en.wikipedia.org/wiki/Solar_System#Distances_and_scales" target="_blank">distances</a>
	</span>
</h1>

<div id="vis"></div>

<script type="text/javascript">


function make(data) {

  /* Set up */
  /* ====== */

  /* Dimensions and base */
  /* ------------------- */

  var margin = {
    top: window.innerHeight * 0.3,
    left: 50,
    bottom: window.innerHeight * 0.4,
    right: 50
  };

  // The chart *and* screen height.
  var height = window.innerHeight - margin.top - margin.bottom;


  // Calculate width
  var mapScale = 1/10e4;
  var maxDist = d3.max(data, function(d) { return d.distance; });

  // The full width of all planets
  var chartWidth = maxDist * mapScale;

  // SVG width will only be as large as screen
  var screenWidth = window.innerWidth - margin.left - margin.right;


  /* SVG */

  var svg = d3.select('#vis')
    .append('svg')
      .attr('width', screenWidth + margin.left + margin.right)
      .attr('height', height + margin.top + margin.bottom)
    .append('g')
      .attr('class', 'chart')
      .attr('transform', 'translate(' + margin.left + ', ' + margin.top + ')');

  var listenerRect = svg
    .append('rect')
      .attr('class', 'listener-rect')
      .attr('x', 0)
      .attr('y', -margin.top)
      .attr('width', screenWidth)
      .attr('height', height + margin.top + margin.bottom)
      .style('opacity', 0);


  /* Scales */
  /* ====== */

  var rExtent = d3.extent(data, function(d) { return d.radius; });

  // Make the sun fit into the height
  // with a little bit of breathing space.
  var rScale = d3.scaleLinear()
    .domain([0, rExtent[1]])
    .range([3, height/2 * 0.9]);

  var xScale = d3.scaleLinear()
    .domain([0, maxDist])
    .range([0, chartWidth]);


  /* Axes components */
  /* --------------- */

  var xAxis = d3.axisBottom(xScale)
      .tickSizeOuter(0)
      .tickPadding(10)
      .tickValues(data.map(function(el) { return el.distance; }))
      .tickFormat(function(d, i) {
        return data[i].planet + ' ' + d3.format(',')(d) + ' km';
      });


  /* Axes draw */
  /* --------- */

  // Drawing the axis
  var xAxisDraw = svg.insert('g', ':first-child')
      .attr('class', 'x axis')
      .call(xAxis);

  // Move the axis-labels and -lines down
  var labelHeight = xAxisDraw.select('text').node().getBBox().height;
  xAxisDraw.attr('transform', 'translate(0, ' + (height + labelHeight * data.length) + ')');

  // Position the axis text
  xAxisDraw.selectAll('text')
    .attr('y', function(d, i) { return -(i * labelHeight + labelHeight); })
    .attr('dx', '-0.15em')
    .attr('dy', '1.15em')
    .style('text-anchor', 'start');

  // Draw the axis lines
  xAxisDraw.selectAll('line')
    .attr('y1', function(d, i) { return -(i * labelHeight + labelHeight); })
    .attr('y2', function(d, i) {
      return -(i * labelHeight + labelHeight + // the start position from axis-y 0
        (data.length-1-i) * labelHeight + // label start to the chart bottom
        height); // the height
    });


  /* Build vis */
  /* ========= */

  /* Sun and planets */
  /* --------------- */

  var gPlanets = svg.insert('g', '.listener-rect').attr('class', 'planet-group');

  var planets = gPlanets.selectAll('.planet')
    .data(data).enter()
    .append('circle')
      .attr('class', 'planet')
      .attr('id', function(d) { return d.planet; })
      .attr('cx', function(d) { return xScale(d.distance); })
      .attr('cy', 0)
      .attr('r', function(d) {
        d.scaledRadius = rScale(d.radius);
        return d.scaledRadius;
      });


  /* Zoom */
  /* ==== */

	// Cross-multiplication to get the minimum zoom so that the furthest away planet
  // (Pluto) just fits on the screen. 0.75 gives some leeway for the label.
  var minZoom = 1 / (chartWidth / window.innerWidth) * 0.75;

  // Define the zoom behaviour
  var zoom = d3.zoom()
    .scaleExtent([minZoom, 20])
    .on('zoom', zoomed);

  // Listen for zoom events
  listenerRect.call(zoom);

  // Zoom function
  function zoomed() {

    // Get the transform
    var transform = d3.event.transform;


    // Lock at the Sun
    transform.x = Math.min(0, transform.x);
    transform.y = 0;

    // Move the planets (geometric)
    gPlanets.attr('transform', transform.toString());

    // Re-scale the x scale
    var xScaleNew = transform.rescaleX(xScale);

    // Semantically zoom and pan the axis
    xAxis.scale(xScaleNew);
    xAxisDraw.call(xAxis);

    // Stagger the axis-labels
    xAxisDraw.selectAll('text')
      .attr('y', function(d, i) { return -(i * labelHeight + labelHeight); })

    // Stagger the axis-lines
    xAxisDraw.selectAll('line')
      .attr('y1', function(d, i) { return -(i * labelHeight + labelHeight); })
      .attr('y2', function(d, i) {
        return -(i * labelHeight + labelHeight + (data.length-1-i) * labelHeight + height);
      });

  } // zoomed()


} // make()


/* Data load and visual */
/* ==================== */

function row(d) {

  return {
    planet: d.planet,
    distance: +d.distance,
    radius: +d.radius,
    text: d.text
  };

}

d3.csv('planets.csv', row, function(error, data) {
  if (error) throw error;
  console.log(data);

  make(data);

});


</script>

</body>

</html>