mirror of
https://github.com/jerryc127/hexo-theme-butterfly.git
synced 2025-09-15 12:58:48 +08:00
85 lines
2.1 KiB
JavaScript
85 lines
2.1 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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// changed by Molunerfinn
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!(function () {
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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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// get user config
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var script = document.getElementById('ribbon'),
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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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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.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 = [{ x: 0, y: height * 0.7 + f }, { x: 0, y: height * 0.7 - f }]
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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] = { x: k, y: n }
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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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})() |