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@tomgp
Last active March 24, 2025 05:13
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Simple D3 clock

A simple clock made with D3

<!DOCTYPE html>
<meta charset="utf-8">
<style>
body {
background: #fff;
}
svg{
stroke: #000;
}
#rim {
fill: none;
stroke: #999;
stroke-width: 3px;
}
.second-hand{
stroke-width:3;
}
.minute-hand{
stroke-width:8;
stroke-linecap:round;
}
.hour-hand{
stroke-width:12;
stroke-linecap:round;
}
</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script src="http://d3js.org/d3.geo.projection.v0.min.js"></script>
<script src="http://d3js.org/topojson.v1.min.js"></script>
<script>
var clockRadius = 200, margin = 50
width = (clockRadius+margin)*2,
height = (clockRadius+margin)*2
hourHandLength = 2*clockRadius/3
minuteHandLength = clockRadius
secondHandLength = clockRadius;
var hourScale = d3.scale.linear()
.range([0,354])
.domain([0,11]);
var minuteScale = secondScale = d3.scale.linear()
.range([0,354])
.domain([0,59]);
var handData = [
{
type:'hour',
value:0,
length:-hourHandLength,
scale:hourScale
},
{
type:'minute',
value:0,
length:-minuteHandLength,
scale:minuteScale
},
{
type:'second',
value:0,
length:-secondHandLength,
scale:secondScale
}
];
function drawClock(){ //create all the clock elements
updateData(); //draw them in the correct starting position
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
var face = svg.append('g')
.attr('id','clock-face')
.attr('transform','translate(' + (clockRadius + margin) + ',' + (clockRadius + margin) + ')');
face.append('circle')
.attr('id','rim')
.attr('x',0)
.attr('y',0)
.attr('r',clockRadius);
var hands = face.append('g').attr('id','clock-hands');
hands.selectAll('line')
.data(handData)
.enter()
.append('line')
.attr('class', function(d){
return d.type + '-hand';
})
.attr('x1',0)
.attr('y1',0)
.attr('x2',0)
.attr('y2',function(d){
return d.length;
})
.attr('transform',function(d){
return 'rotate('+ d.scale(d.value) +')';
});
}
function moveHands(){
d3.select('#clock-hands').selectAll('line')
.data(handData)
.transition()
.attr('transform',function(d){
return 'rotate('+ d.scale(d.value) +')';
});
}
function updateData(){
var t = new Date();
handData[0].value = (t.getHours() % 11) + t.getMinutes()/60 ;
handData[1].value = t.getMinutes();
handData[2].value = t.getSeconds();
}
drawClock();
setInterval(function(){
updateData();
moveHands();
}, 1000);
d3.select(self.frameElement).style("height", height + "px");
</script>
@blech
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blech commented Nov 1, 2013

Thanks for this: it was a fantastic foundation for my DST transition visualisation.

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