chapter_12/04_radios.html

<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="utf-8">
		<title>D3: Using radio buttons to set filter threshold value</title>
		<script type="text/javascript" src="../d3.js"></script>
		<style type="text/css">
			
			p {
				font-family: Helvetica, sans-serif;
				font-size: 12px;
			}

			input[type=radio] {
				margin-left: 40px;
			}

		</style>
	</head>
	<body>

		<p>
			<input type="radio" name="filterPreset" value="0" checked="true"> 0
			<input type="radio" name="filterPreset" value="200"> 200
			<input type="radio" name="filterPreset" value="500"> 500
			<input type="radio" name="filterPreset" value="800"> 800
		</p>

		<script type="text/javascript">

			//Width and height
			var w = 600;
			var h = 300;
			var padding = 40;
			
			//Dynamic, random dataset
			var dataset = [];					//Initialize empty array
			var numDataPoints = 200;			//Number of dummy data points to create
			var xRange = 1000;					//Max range of new x values
			var yRange = 1000;					//Max range of new y values
			for (var i = 0; i < numDataPoints; i++) {					//Loop numDataPoints times
				var newNumber1 = Math.floor(Math.random() * xRange);	//New random integer
				var newNumber2 = Math.floor(Math.random() * yRange);	//New random integer
				dataset.push([newNumber1, newNumber2]);					//Add new number to array
			}

			//Create scale functions
			var xScale = d3.scaleLinear()
								 .domain([0, 1000])
								 .range([padding, w - padding / 2]);

			var yScale = d3.scaleLinear()
								 .domain([0, 1000])
								 .range([h - padding, padding / 2]);

			//Define X axis
			var xAxis = d3.axisBottom()
							  .scale(xScale)
							  .ticks(5);

			//Define Y axis
			var yAxis = d3.axisLeft()
							  .scale(yScale)
							  .ticks(5);

			//Create SVG element
			var svg = d3.select("body")
						.append("svg")
						.attr("width", w)
						.attr("height", h);

			//Create circles
			var allCircles = svg.selectAll("circle")
			   .data(dataset)
			   .enter()
			   .append("circle")
			   .attr("cx", function(d) {
			   		return xScale(d[0]);
			   })
			   .attr("cy", function(d) {
			   		return yScale(d[1]);
			   })
			   .attr("r", 2.5);
			
			//Create X axis
			svg.append("g")
				.attr("class", "axis")
				.attr("transform", "translate(0," + (h - padding) + ")")
				.call(xAxis);
			
			//Create Y axis
			svg.append("g")
				.attr("class", "axis")
				.attr("transform", "translate(" + padding + ",0)")
				.call(yAxis);

			//On radio button change, update styling
			d3.selectAll("input")
				.on("click", function() {

					var threshold = +d3.select(this).node().value;
					
					allCircles.attr("fill", "black")
						.filter(function(d) {
							return d[0] <= threshold;
						})
						.attr("fill", "red");

				});


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