实现我博客旁边的线条效果 html canvas-nest.js 源码

/** ????* Copyright (c) 2016 hustcc ????* License: MIT ????* Version: %%GULP_INJECT_VERSION%% ????* GitHub: https://github.com/hustcc/canvas-nest.js ???**/ ???! function() { ?????//封装方法，压缩之后减少文件大小 ?????function get_attribute(node, attr, default_value) { ???????return node.getAttribute(attr) || default_value; ?????} ?????//封装方法，压缩之后减少文件大小 ?????function get_by_tagname(name) { ???????return document.getElementsByTagName(name); ?????} ?????//获取配置参数 ?????function get_config_option() { ???????var scripts = get_by_tagname("script"), ?????????script_len = scripts.length, ?????????script = scripts[script_len - 1]; //当前加载的script ???????return { ?????????l: script_len, //长度，用于生成id用 ?????????z: get_attribute(script, "zIndex", -1), //z-index ?????????o: get_attribute(script, "opacity", 0.5), //opacity ?????????c: get_attribute(script, "color", "0,0,0"), //color ?????????n: get_attribute(script, "count", 99) //count ???????}; ?????} ?????//设置canvas的高宽 ?????function set_canvas_size() { ???????canvas_width = the_canvas.width = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth, ???????canvas_height = the_canvas.height = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight; ?????} ?????????//绘制过程 ?????function draw_canvas() { ???????context.clearRect(0, 0, canvas_width, canvas_height); ???????//随机的线条和当前位置联合数组 ???????var e, i, d, x_dist, y_dist, dist; //临时节点 ???????//遍历处理每一个点 ???????random_points.forEach(function(r, idx) { ?????????r.x += r.xa, ?????????r.y += r.ya, //移动 ?????????r.xa *= r.x > canvas_width || r.x < 0 ? -1 : 1, ?????????r.ya *= r.y > canvas_height || r.y < 0 ? -1 : 1, //碰到边界，反向反弹 ?????????context.fillRect(r.x - 0.5, r.y - 0.5, 1, 1); //绘制一个宽高为1的点 ?????????//从下一个点开始 ?????????for (i = idx + 1; i < all_array.length; i++) { ???????????e = all_array[i]; ???????????// 当前点存在 ???????????if (null !== e.x && null !== e.y) { ?????????????x_dist = r.x - e.x; //x轴距离 l ?????????????y_dist = r.y - e.y; //y轴距离 n ?????????????dist = x_dist * x_dist + y_dist * y_dist; //总距离, m ?????????????????dist < e.max && (e === current_point && dist >= e.max / 2 && (r.x -= 0.03 * x_dist, r.y -= 0.03 * y_dist), //靠近的时候加速 ???????????????d = (e.max - dist) / e.max, ???????????????context.beginPath(), ???????????????context.lineWidth = d / 2, ???????????????context.strokeStyle = "rgba(" + config.c + "," + (d + 0.2) + ")", ???????????????context.moveTo(r.x, r.y), ???????????????context.lineTo(e.x, e.y), ???????????????context.stroke()); ???????????} ?????????} ???????}), frame_func(draw_canvas); ?????} ?????//创建画布，并添加到body中 ?????var the_canvas = document.createElement("canvas"), //画布 ???????config = get_config_option(), //配置 ???????canvas_id = "c_n" + config.l, //canvas id ???????context = the_canvas.getContext("2d"), canvas_width, canvas_height, ???????frame_func = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function(func) { ?????????window.setTimeout(func, 1000 / 45); ???????}, random = Math.random, ???????current_point = { ?????????x: null, //当前鼠标x ?????????y: null, //当前鼠标y ?????????max: 20000 // 圈半径的平方 ???????}, ???????all_array; ?????the_canvas.id = canvas_id; ?????the_canvas.style.cssText = "position:fixed;top:0;left:0;z-index:" + config.z + ";opacity:" + config.o; ?????get_by_tagname("body")[0].appendChild(the_canvas); ?????????//初始化画布大小 ?????set_canvas_size(); ?????window.onresize = set_canvas_size; ?????//当时鼠标位置存储，离开的时候，释放当前位置信息 ?????window.onmousemove = function(e) { ???????e = e || window.event; ???????current_point.x = e.clientX; ???????current_point.y = e.clientY; ?????}, window.onmouseout = function() { ???????current_point.x = null; ???????current_point.y = null; ?????}; ?????//随机生成config.n条线位置信息 ?????for (var random_points = [], i = 0; config.n > i; i++) { ???????var x = random() * canvas_width, //随机位置 ?????????y = random() * canvas_height, ?????????xa = 2 * random() - 1, //随机运动方向 ?????????ya = 2 * random() - 1; ???????// 随机点 ???????random_points.push({ ?????????x: x, ?????????y: y, ?????????xa: xa, ?????????ya: ya, ?????????max: 6000 //沾附距离 ???????}); ?????} ?????all_array = random_points.concat([current_point]); ?????//0.1秒后绘制 ?????setTimeout(function() { ???????draw_canvas(); ?????}, 100); ???}();