A slightly updated version of OMG Particles! using Canvas and smooth interpolation towards the mouse location.
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March 2, 2020 17:20
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OMG Particles II
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license: gpl-3.0 |
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<!DOCTYPE html> | |
<meta charset="utf-8"> | |
<style> | |
body { | |
margin: 0; | |
background: #111; | |
min-width: 960px; | |
} | |
</style> | |
<body> | |
<script src="//d3js.org/d3.v3.min.js"></script> | |
<script> | |
var width = Math.max(960, innerWidth), | |
height = Math.max(500, innerHeight); | |
var x1 = width / 2, | |
y1 = height / 2, | |
x0 = x1, | |
y0 = y1, | |
i = 0, | |
r = 200, | |
τ = 2 * Math.PI; | |
var canvas = d3.select("body").append("canvas") | |
.attr("width", width) | |
.attr("height", height) | |
.on("ontouchstart" in document ? "touchmove" : "mousemove", move); | |
var context = canvas.node().getContext("2d"); | |
context.globalCompositeOperation = "lighter"; | |
context.lineWidth = 2; | |
d3.timer(function() { | |
context.clearRect(0, 0, width, height); | |
var z = d3.hsl(++i % 360, 1, .5).rgb(), | |
c = "rgba(" + z.r + "," + z.g + "," + z.b + ",", | |
x = x0 += (x1 - x0) * .1, | |
y = y0 += (y1 - y0) * .1; | |
d3.select({}).transition() | |
.duration(2000) | |
.ease(Math.sqrt) | |
.tween("circle", function() { | |
return function(t) { | |
context.strokeStyle = c + (1 - t) + ")"; | |
context.beginPath(); | |
context.arc(x, y, r * t, 0, τ); | |
context.stroke(); | |
}; | |
}); | |
}); | |
function move() { | |
var mouse = d3.mouse(this); | |
x1 = mouse[0]; | |
y1 = mouse[1]; | |
d3.event.preventDefault(); | |
} | |
</script> |
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From what I know, d3.select() api allows empty selections. In this case, it is being used to make use of other apis (transition, tween) which are available on selections even though it is an empty one.