A test of the d3-timer module.
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| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <canvas width="960" height="500"></canvas> | |
| <script> | |
| /* https://github.com/d3/d3-timer Copyright 2015 Mike Bostock */ | |
| "undefined"==typeof requestAnimationFrame&&(requestAnimationFrame="undefined"!=typeof window&&(window.msRequestAnimationFrame||window.mozRequestAnimationFrame||window.webkitRequestAnimationFrame||window.oRequestAnimationFrame)||function(e){return setTimeout(e,17)}),function(e,t){"object"==typeof exports&&"undefined"!=typeof module?t(exports):"function"==typeof define&&define.amd?define(["exports"],t):t(e.timer={})}(this,function(e){"use strict";function t(){l=s=0,c=1/0,n(a())}function n(e){if(!l){var n=e-Date.now();n>24?c>e&&(s&&clearTimeout(s),s=setTimeout(t,n),c=e):(s&&(s=clearTimeout(s),c=1/0),l=requestAnimationFrame(t))}}function i(e,t){this.callback=e,this.time=t,this.flush=!1,this.next=null}function o(e,t,o){o=null==o?Date.now():+o,null!=t&&(o+=+t);var u=new i(e,o);r?r.next=u:m=u,r=u,n(o)}function u(e,t,n){n=null==n?Date.now():+n,null!=t&&(n+=+t),f.callback=e,f.time=n}function a(e){e=null==e?Date.now():+e;var t=f;for(f=m;f;)e>=f.time&&(f.flush=f.callback(e-f.time,e)),f=f.next;f=t,e=1/0;for(var n,i=m;i;)i.flush?i=n?n.next=i.next:m=i.next:(i.time<e&&(e=i.time),i=(n=i).next);return r=n,e}var m,r,f,l,s,c=1/0;e.timer=o,e.timerReplace=u,e.timerFlush=a}); | |
| var canvas = document.querySelector("canvas"), | |
| context = canvas.getContext("2d"), | |
| width = canvas.width, | |
| height = canvas.height, | |
| radius = 2.5, | |
| minDistance = 80, | |
| maxDistance = 100, | |
| minDistance2 = minDistance * minDistance, | |
| maxDistance2 = maxDistance * maxDistance; | |
| var tau = 2 * Math.PI, | |
| n = 100, | |
| particles = new Array(n); | |
| for (var i = 0; i < n; ++i) { | |
| particles[i] = { | |
| x: width * Math.random(), | |
| y0: height * Math.random(), | |
| v: .1 * (Math.random() - .5) | |
| }; | |
| } | |
| timer.timer(function(elapsed) { | |
| context.clearRect(0, 0, width, height); | |
| for (var i = 0; i < n; ++i) { | |
| for (var j = i + 1; j < n; ++j) { | |
| var pi = particles[i], | |
| pj = particles[j], | |
| dx = pi.x - pj.x, | |
| dy = pi.y - pj.y, | |
| d2 = dx * dx + dy * dy; | |
| if (d2 < maxDistance2) { | |
| context.globalAlpha = d2 > minDistance2 ? (maxDistance2 - d2) / (maxDistance2 - minDistance2) : 1; | |
| context.beginPath(); | |
| context.moveTo(pi.x, pi.y); | |
| context.lineTo(pj.x, pj.y); | |
| context.stroke(); | |
| } | |
| } | |
| } | |
| context.globalAlpha = 1; | |
| for (var i = 0; i < n; ++i) { | |
| var p = particles[i]; | |
| p.y = p.y0 + elapsed * p.v; | |
| if (p.y > height + maxDistance) p.x = width * Math.random(), p.y0 -= height + 2 * maxDistance; | |
| else if (p.y < -maxDistance) p.x = width * Math.random(), p.y0 += height + 2 * maxDistance; | |
| context.beginPath(); | |
| context.arc(p.x, p.y, radius, 0, tau); | |
| context.fill(); | |
| } | |
| }); | |
| </script> |
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