mirror of
https://github.com/jerryc127/hexo-theme-butterfly.git
synced 2025-09-15 12:58:48 +08:00
108 lines
2.4 KiB
JavaScript
108 lines
2.4 KiB
JavaScript
/**
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* Copyright (c) 2016 hustcc
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* License: MIT
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* Version: v1.0.1
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* GitHub: https://github.com/hustcc/ribbon.js
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**/
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!(function() {
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var script = document.getElementById("ribbon");
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var mb = script.getAttribute("mobile");
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if (
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mb == "false" &&
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/Android|webOS|iPhone|iPod|iPad|BlackBerry/i.test(navigator.userAgent)
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) {
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return;
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}
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config = {
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z: attr(script, "zIndex", -1), // z-index
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a: attr(script, "alpha", 0.6), // alpha
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s: attr(script, "size", 90), // size
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c: attr(script, "data-click", true) // click-to-change
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};
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function attr(node, attr, default_value) {
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if (default_value === true) {
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return node.getAttribute(attr) || default_value;
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}
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return Number(node.getAttribute(attr)) || default_value;
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}
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var canvas = document.createElement("canvas"),
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g2d = canvas.getContext("2d"),
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pr = window.devicePixelRatio || 1,
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width = window.innerWidth,
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height = window.innerHeight,
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f = config.s,
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q,
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t,
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m = Math,
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r = 0,
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pi = m.PI * 2,
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cos = m.cos,
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random = m.random;
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canvas.id = "ribbon-canvas";
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canvas.width = width * pr;
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canvas.height = height * pr;
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g2d.scale(pr, pr);
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g2d.globalAlpha = config.a;
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canvas.style.cssText =
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"opacity: " +
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config.a +
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";position:fixed;top:0;left:0;z-index: " +
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config.z +
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";width:100%;height:100%;pointer-events:none;";
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// create canvas
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document.getElementsByTagName("body")[0].appendChild(canvas);
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function redraw() {
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g2d.clearRect(0, 0, width, height);
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q = [
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{
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x: 0,
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y: height * 0.7 + f
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},
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{
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x: 0,
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y: height * 0.7 - f
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}
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];
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while (q[1].x < width + f) draw(q[0], q[1]);
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}
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function draw(i, j) {
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g2d.beginPath();
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g2d.moveTo(i.x, i.y);
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g2d.lineTo(j.x, j.y);
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var k = j.x + (random() * 2 - 0.25) * f,
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n = line(j.y);
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g2d.lineTo(k, n);
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g2d.closePath();
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r -= pi / -50;
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g2d.fillStyle =
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"#" +
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(
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((cos(r) * 127 + 128) << 16) |
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((cos(r + pi / 3) * 127 + 128) << 8) |
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(cos(r + (pi / 3) * 2) * 127 + 128)
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).toString(16);
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g2d.fill();
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q[0] = q[1];
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q[1] = {
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x: k,
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y: n
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};
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}
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function line(p) {
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t = p + (random() * 2 - 1.1) * f;
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return t > height || t < 0 ? line(p) : t;
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}
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if (config.c !== "false") {
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document.onclick = redraw;
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document.ontouchstart = redraw;
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}
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redraw();
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})();
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