怎么在JavaScript中利用canvas实现一个圆形流水动画
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这篇文章将为大家详细讲解有关怎么在JavaScript中利用canvas实现一个圆形流水动画，文章内容质量较高，因此小编分享给大家做个参考，希望大家阅读完这篇文章后对相关知识有一定的了解。
JavaScript的特点
1.JavaScript主要用来向HTML页面添加交互行为。2.JavaScript可以直接嵌入到HTML页面，但写成单独的js文件有利于结构和行为的分离。3.JavaScript具有跨平台特性，在绝大多数浏览器的支持下，可以在多种平台下运行。
index.html
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title> <!-- <link rel="stylesheet" href="style.css" > --></head><body> <script class="lazy" data-src="main.js"></script></body></html>main.js
(function() { var ctx, w, h, cx, cy, PI, PI_HALF, cos, sin, random, lineWidth, C, rings, ringsLength, data; ctx = document.createElement('canvas').getContext('2d'); w = 600; h = 600; cx = (w / 2); cy = (h / 2); rings = []; ringsLength = 0; PI = Math.PI; PI_HALF = PI / 2; cos = Math.cos; sin = Math.sin; random = Math.random; lineWidth = 0.2; C = ["#ABF8FF", "#E76B76", "#1D2439", "#4F3762", "#67F9FF", "#0C0F18"]; data = [ [ {t:80, r:(cx-10), d:40, s:30, c:C[1]}, {t:60, r:(cx-20), d:40, s:80, c:C[2]}, {t:20, r:(cx-30), d:20, s:80, c:C[2]}, ], [ {t:80, r:(cx-80), d:40, s:40, c:C[4]}, {t:80, r:(cx-90), d:20, s:40, c:C[4]}, {t:20, r:(cx-100), d:20, s:40, c:C[2]}, {t:40, r:(cx-110), d:20, s:40, c:C[2]}, ], [ {t:60, r:(cx-160), d:40, s:20, c:C[2]}, {t:20, r:(cx-170), d:30, s:60, c:C[2]}, {t:40, r:(cx-180), d:40, s:60, c:C[2]}, ], [ {t:40, r:(cx-230), d:40, s:20, c:C[5]}, {t:20, r:(cx-240), d:20, s:10, c:C[5]}, ], [ {t:10, r:(cx-290), d:10, s:10, c:C[4]} ] ]; ctx.canvas.width = w; ctx.canvas.height = h; document.body.appendChild(ctx.canvas); data.forEach(function(group) { var ring = []; group.forEach(function(orbit, i) { var total_particles, index; total_particles = orbit.t; index = 0; for (; index < total_particles; index++) { var radius, distance, speed, color, opacity; radius = orbit.r; distance = orbit.d; speed = random() / orbit.s; speed = i % 2 ? speed : speed * -1; color = orbit.c; opacity = orbit.o; ring.push(new P(radius, distance, speed, color, opacity)); radius = distance = speed = color = opacity = null; } }); rings.push(ring); }); ringsLength = rings.length; function P(radius, distance, speed, color) { this.a = PI / 180; this.d = distance; this.d2 = (this.d * this.d); this.x = cx + radius * cos(this.a); this.y = cy + radius * sin(this.a); this.c = color; this.r = (random() * 8); this.R = random() > 0.5 ? radius : radius - 5; this.s = speed; this.pos = random() * 360; } function draw() { var i, j, k, xd, yd, d, ring, ringLength, ringLength3, particle, p2; ctx.beginPath(); ctx.globalCompositeOperation = "source-over"; ctx.rect(0, 0 , w, h); ctx.fillStyle = "#151a28"; ctx.fill(); ctx.closePath(); for (i = 0; i < ringsLength; i++) { ring = rings[i]; ringLength = ring.length; ringLength3 = ringLength - 100; for (j = 0; j < ringLength; j++) { particle = ring[j]; particle.x = cx + particle.R * sin(PI_HALF + particle.pos); particle.y = cy + particle.R * cos(PI_HALF + particle.pos); particle.pos += particle.s; ctx.beginPath(); ctx.globalAlpha = 0.12; ctx.globalCompositeOperation = "lighter"; ctx.fillStyle = particle.c; ctx.arc(particle.x, particle.y, particle.r, PI * 2, false); ctx.fill(); ctx.closePath(); for (k = 0; k < ringLength3; k++) { p2 = ring[k]; yd = p2.y - particle.y; xd = p2.x - particle.x; d = ((xd * xd) + (yd * yd)); if (d < particle.d2) { ctx.beginPath(); ctx.globalAlpha = 1; ctx.lineWidth = lineWidth; ctx.moveTo(particle.x, particle.y); ctx.lineTo(p2.x, p2.y); ctx.strokeStyle = p2.c; ctx.stroke(); ctx.closePath(); } } } } } function loop() { draw(); requestAnimationFrame(loop); } loop(); })();关于怎么在JavaScript中利用canvas实现一个圆形流水动画就分享到这里了，希望以上内容可以对大家有一定的帮助，可以学到更多知识。如果觉得文章不错，可以把它分享出去让更多的人看到。
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