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@ameyms
Created February 22, 2014 08:41
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D3 Gauge

A simple gauge chart using d3 Inspired by Jake Trent's Codepen snippet

To move the pointer needle, type in following code in you javascript console

needle.moveTo(.25)
var needle;
(function(){
var arc, arcEndRad, arcStartRad, barWidth, chart, chartInset, degToRad,
endPadRad, height, margin, numSections, padRad, percToDeg, percToRad,
percent, radius, sectionIndx, sectionPerc, startPadRad, svg, totalPercent, width, _i;
percent = .65;
numSections = 1;
sectionPerc = 1 / numSections / 2;
padRad = 0.05;
chartInset = 10;
// Orientation of gauge:
totalPercent = .75;
el = d3.select('.chart-gauge');
margin = {
top: 20,
right: 20,
bottom: 30,
left: 20
};
width = el[0][0].offsetWidth - margin.left - margin.right;
height = width;
radius = Math.min(width, height) / 2;
barWidth = 40 * width / 300;
/*
Utility methods
*/
percToDeg = function(perc) {
return perc * 360;
};
percToRad = function(perc) {
return degToRad(percToDeg(perc));
};
degToRad = function(deg) {
return deg * Math.PI / 180;
};
// Create SVG element
svg = el.append('svg').attr('width', width + margin.left + margin.right).attr('height', height + margin.top + margin.bottom);
// Add layer for the panel
chart = svg.append('g').attr('transform', "translate(" + ((width + margin.left) / 2) + ", " + ((height + margin.top) / 2) + ")");
for (sectionIndx = _i = 1; _i <= numSections; ++_i) {
sectionIndx = _i;
arcStartRad = percToRad(totalPercent);
arcEndRad = arcStartRad + percToRad(sectionPerc);
totalPercent += sectionPerc;
// Leave margin for intermediate sections
startPadRad = sectionIndx === 0 ? 0 : padRad / 2;
endPadRad = sectionIndx === numSections ? 0 : padRad / 2;
arc = d3.svg.arc().outerRadius(radius - chartInset).innerRadius(radius - chartInset - barWidth)
.startAngle(arcStartRad + startPadRad).endAngle(arcEndRad - endPadRad);
chart.append('path').attr('class', "arc chart-color" + sectionIndx).attr('d', arc);
}
var Needle = (function() {
/**
* Helper function that returns the `d` value
* for moving the needle
**/
var recalcPointerPos = function(perc) {
var centerX, centerY, leftX, leftY, rightX, rightY, thetaRad, topX, topY;
thetaRad = percToRad(perc / 2);
centerX = 0;
centerY = 0;
topX = centerX - this.len * Math.cos(thetaRad);
topY = centerY - this.len * Math.sin(thetaRad);
leftX = centerX - this.radius * Math.cos(thetaRad - Math.PI / 2);
leftY = centerY - this.radius * Math.sin(thetaRad - Math.PI / 2);
rightX = centerX - this.radius * Math.cos(thetaRad + Math.PI / 2);
rightY = centerY - this.radius * Math.sin(thetaRad + Math.PI / 2);
return "M " + leftX + " " + leftY + " L " + topX + " " + topY + " L " + rightX + " " + rightY;
};
function Needle(el) {
this.el = el;
this.len = width / 3;
this.radius = this.len / 6;
}
Needle.prototype.render = function(perc) {
this.el.append('circle').attr('class', 'needle-center').attr('cx', 0).attr('cy', 0).attr('r', this.radius);
return this.el.append('path').attr('class', 'needle').attr('d', recalcPointerPos.call(this, perc));
};
Needle.prototype.moveTo = function(perc) {
var self;
self = this;
return this.el.transition().delay(500).ease('elastic').duration(3000).selectAll('.needle').tween('progress', function() {
return function(percentOfPercent) {
var progress = percentOfPercent * perc;
return d3.select(this).attr('d', recalcPointerPos.call(self, progress));
};
});
};
return Needle;
})();
needle = new Needle(chart);
needle.render(0);
needle.moveTo(percent);
})();
<!DOCTYPE html>
<html>
<head>
<style type="text/css">
.chart-gauge
{
width: 400px;
margin: 100px auto
}
.chart-color1
{
fill: steelblue;
}
.chart-color2
{
fill: #DEA82C;
}
.chart-color3
{
fill: #E9621A;
}
.chart-color4
{
fill: ##e92213;
}
.needle, .needle-center
{
fill: #464A4F;
}
svg {
font: 10px sans-serif;
}
</style>
</head>
<body>
<div id="foo"></div>
<div class="chart-gauge"></div>
<script src="http://d3js.org/d3.v3.min.js" charset="utf-8"></script>
<script type="text/javascript" src="d3_gauge.js"></script>
</body>
</html>
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