js

var ctx = document.querySelector('canvas').getContext('2d') ctx.canvas.width = window.innerWidth ctx.canvas.height = window.innerHeight var sparks = [] var fireworks = [] var i = 20; while (i--) { fireworks.push( new Firework(Math.random() * window.innerWidth, window.innerHeight * Math.random()) ) } render() function render() { setTimeout(render, 1000 / 60) ctx.fillStyle = 'rgba(0, 0, 0, 0.1)'; ctx.fillRect(0, 0, ctx.canvas.width, ctx.canvas.height) for (var firework of fireworks) { if (firework.dead) continue firework.move() firework.draw() } for (var spark of sparks) { if (spark.dead) continue spark.move() spark.draw() } if (Math.random() < 0.05) { fireworks.push(new Firework()) } } function Spark(x, y, color) { this.x = x this.y = y this.dir = Math.random() * (Math.PI * 2) this.dead = false this.color = color this.speed = Math.random() * 3 + 3; this.walker = new Walker({ radius: 20, speed: 0.25 }) this.gravity = 0.25 this.dur = this.speed / 0.1 this.move = function () { this.dur-- if (this.dur < 0) this.dead = true if (this.speed < 0) return if (this.speed > 0) this.speed -= 0.1 var walk = this.walker.step() this.x += Math.cos(this.dir + walk) * this.speed this.y += Math.sin(this.dir + walk) * this.speed this.y += this.gravity this.gravity += 0.05 } this.draw = function () { drawCircle(this.x, this.y, 3, this.color) } } function Firework(x, y) { this.xmove = new Walker({ radius: 10, speed: 0.5 }) this.x = x || Math.random() * ctx.canvas.width this.y = y || ctx.canvas.height this.height = Math.random() * ctx.canvas.height / 2 this.dead = false this.color = randomColor() this.move = function () { this.x += this.xmove.step() if (this.y > this.height) this.y -= 1; else this.burst() } this.draw = function () { drawCircle(this.x, this.y, 1, this.color) } this.burst = function () { this.dead = true var i = 100; while (i--) sparks.push(new Spark(this.x, this.y, this.color)) } } function drawCircle(x, y, radius, color) { color = color || '#FFF' ctx.fillStyle = color ctx.fillRect(x - radius / 2, y - radius / 2, radius, radius) } function randomColor() { return ['#6ae5ab', '#88e3b2', '#36b89b', '#7bd7ec', '#66cbe1'][Math.floor(Math.random() * 5)]; } function Walker(options) { this.step = function () { this.direction = Math.sign(this.target) * this.speed this.value += this.direction this.target ? this.target -= this.direction : (this.value) ? (this.wander) ? this.target = this.newTarget() : this.target = -this.value : this.target = this.newTarget() return this.direction } this.newTarget = function () { return Math.round(Math.random() * (this.radius * 2) - this.radius) } this.start = 0 this.value = 0 this.radius = options.radius this.target = this.newTarget() this.direction = Math.sign(this.target) this.wander = options.wander this.speed = options.speed || 1 }

实现三

 

html

<canvas id="cas" style="background-color:rgba(0,5,24,1)" width="1235" height="680">浏览器不支持canvas</canvas> <div class="city"> <img src="city.png" alt=""> </div> <img src="moon.png" alt="" id="moon" style="visibility: hidden;"> <div style="display:none"> <div class="shape">新年快乐</div> <div class="shape">阖家欢乐</div> <div class="shape">万事如意</div> <div class="shape">心想事成</div> </div>

css

body { margin: 0; padding: 0; overflow: hidden; } .city { width: 100%; position: fixed; bottom: 0px; z-index: 100; } .city img { width: 100%; }

js

var canvas = document.getElementById("cas"); var ocas = document.createElement("canvas"); var octx = ocas.getContext("2d"); var ctx = canvas.getContext("2d"); ocas.width = canvas.width = window.innerWidth; ocas.height = canvas.height = window.innerHeight; var bigbooms = []; window.onload = function () { initAnimate() } function initAnimate() { drawBg(); lastTime = new Date(); animate(); } var lastTime; function animate() { ctx.save(); ctx.fillStyle = "rgba(0,5,24,0.1)"; ctx.fillRect(0, 0, canvas.width, canvas.height); ctx.restore(); var newTime = new Date(); if (newTime - lastTime > 500 + (window.innerHeight - 767) / 2) { var random = Math.random() * 100 > 2 ? true : false; var x = getRandom(canvas.width / 5, canvas.width * 4 / 5); var y = getRandom(50, 200); if (random) { var bigboom = new Boom(getRandom(canvas.width / 3, canvas.width * 2 / 3), 2, "#FFF", { x: x, y: y }); bigbooms.push(bigboom) } else { var bigboom = new Boom(getRandom(canvas.width / 3, canvas.width * 2 / 3), 2, "#FFF", { x: canvas.width / 2, y: 200 }, document.querySelectorAll(".shape")[parseInt(getRandom(0, document.querySelectorAll( ".shape").length))]); bigbooms.push(bigboom) } lastTime = newTime; } stars.foreach(function () { this.paint(); }) drawMoon(); bigbooms.foreach(function (index) { var that = this; if (!this.dead) { this._move(); this._drawLight(); } else { this.booms.foreach(function (index) { if (!this.dead) { this.moveTo(index); } else if (index === that.booms.length - 1) { bigbooms[bigbooms.indexOf(that)] = null; } }) } }); raf(animate); } function drawMoon() { var moon = document.getElementById("moon"); var centerX = canvas.width - 200, centerY = 100, width = 80; if (moon.complete) { ctx.drawImage(moon, centerX, centerY, width, width) } else { moon.onload = function () { ctx.drawImage(moon, centerX, centerY, width, width) } } var index = 0; for (var i = 0; i < 10; i++) { ctx.save(); ctx.beginPath(); ctx.arc(centerX + width / 2, centerY + width / 2, width / 2 + index, 0, 2 * Math.PI); ctx.fillStyle = "rgba(240,219,120,0.005)"; index += 2; ctx.fill(); ctx.restore(); } } Array.prototype.foreach = function (callback) { for (var i = 0; i < this.length; i++) { if (this[i] !== null) callback.apply(this[i], [i]) } } var raf = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function (callback) { window.setTimeout(callback, 1000 / 60); }; canvas.onclick = function () { var x = event.clientX; var y = event.clientY; var bigboom = new Boom(getRandom(canvas.width / 3, canvas.width * 2 / 3), 2, "#FFF", { x: x, y: y }); bigbooms.push(bigboom) } var Boom = function (x, r, c, boomArea, shape) { this.booms = []; this.x = x; this.y = (canvas.height + r); this.r = r; this.c = c; this.shape = shape || false; this.boomArea = boomArea; this.theta = 0; this.dead = false; this.ba = parseInt(getRandom(80, 200)); } Boom.prototype = { _paint: function () { ctx.save(); ctx.beginPath(); ctx.arc(this.x, this.y, this.r, 0, 2 * Math.PI); ctx.fillStyle = this.c; ctx.fill(); ctx.restore(); }, _move: function () { var dx = this.boomArea.x - this.x, dy = this.boomArea.y - this.y; this.x = this.x + dx * 0.01; this.y = this.y + dy * 0.01; if (Math.abs(dx) <= this.ba && Math.abs(dy) <= this.ba) { if (this.shape) { this._shapBoom(); } else this._boom(); this.dead = true; } else { this._paint(); } }, _drawLight: function () { ctx.save(); ctx.fillStyle = "rgba(255,228,150,0.3)"; ctx.beginPath(); ctx.arc(this.x, this.y, this.r + 3 * Math.random() + 1, 0, 2 * Math.PI); ctx.fill(); ctx.restore(); }, _boom: function () { var fragNum = getRandom(30, 200); var style = getRandom(0, 10) >= 5 ? 1 : 2; var color; if (style === 1) { color = { a: parseInt(getRandom(128, 255)), b: parseInt(getRandom(128, 255)), c: parseInt(getRandom(128, 255)) } } var fanwei = parseInt(getRandom(300, 400)); for (var i = 0; i < fragNum; i++) { if (style === 2) { color = { a: parseInt(getRandom(128, 255)), b: parseInt(getRandom(128, 255)), c: parseInt(getRandom(128, 255)) } } var a = getRandom(-Math.PI, Math.PI); var x = getRandom(0, fanwei) * Math.cos(a) + this.x; var y = getRandom(0, fanwei) * Math.sin(a) + this.y; var radius = getRandom(0, 2) var frag = new Frag(this.x, this.y, radius, color, x, y); this.booms.push(frag); } }, _shapBoom: function () { var that = this; putValue(ocas, octx, this.shape, 5, function (dots) { var dx = canvas.width / 2 - that.x; var dy = canvas.height / 2 - that.y; for (var i = 0; i < dots.length; i++) { color = { a: dots[i].a, b: dots[i].b, c: dots[i].c } var x = dots[i].x; var y = dots[i].y; var radius = 1; var frag = new Frag(that.x, that.y, radius, color, x - dx, y - dy); that.booms.push(frag); } }) } } function putValue(canvas, context, ele, dr, callback) { context.clearRect(0, 0, canvas.width, canvas.height); var img = new Image(); if (ele.innerHTML.indexOf("img") >= 0) { img.src = ele.getElementsByTagName("img")[0].src; imgload(img, function () { context.drawImage(img, canvas.width / 2 - img.width / 2, canvas.height / 2 - img.width / 2); dots = getimgData(canvas, context, dr); callback(dots); }) } else { var text = ele.innerHTML; context.save(); var fontSize = 200; context.font = fontSize + "px 宋体 bold"; context.textAlign = "center"; context.textBaseline = "middle"; context.fillStyle = "rgba(" + parseInt(getRandom(128, 255)) + "," + parseInt(getRandom(128, 255)) + "," + parseInt(getRandom(128, 255)) + " , 1)"; context.fillText(text, canvas.width / 2, canvas.height / 2); context.restore(); dots = getimgData(canvas, context, dr); callback(dots); } } function imgload(img, callback) { if (img.complete) { callback.call(img); } else { img.onload = function () { callback.call(this); } } } function getimgData(canvas, context, dr) { var imgData = context.getImageData(0, 0, canvas.width, canvas.height); context.clearRect(0, 0, canvas.width, canvas.height); var dots = []; for (var x = 0; x < imgData.width; x += dr) { for (var y = 0; y < imgData.height; y += dr) { var i = (y * imgData.width + x) * 4; if (imgData.data[i + 3] > 128) { var dot = { x: x, y: y, a: imgData.data[i], b: imgData.data[i + 1], c: imgData.data[i + 2] }; dots.push(dot); } } } return dots; } function getRandom(a, b) { return Math.random() * (b - a) + a; } var maxRadius = 1, stars = []; function drawBg() { for (var i = 0; i < 100; i++) { var r = Math.random() * maxRadius; var x = Math.random() * canvas.width; var y = Math.random() * 2 * canvas.height - canvas.height; var star = new Star(x, y, r); stars.push(star); star.paint() } } var Star = function (x, y, r) { this.x = x; this.y = y; this.r = r; } Star.prototype = { paint: function () { ctx.save(); ctx.beginPath(); ctx.arc(this.x, this.y, this.r, 0, 2 * Math.PI); ctx.fillStyle = "rgba(255,255,255," + this.r + ")"; ctx.fill(); ctx.restore(); } } var focallength = 250; var Frag = function (centerX, centerY, radius, color, tx, ty) { this.tx = tx; this.ty = ty; this.x = centerX; this.y = centerY; this.dead = false; this.centerX = centerX; this.centerY = centerY; this.radius = radius; this.color = color; } Frag.prototype = { paint: function () { ctx.save(); ctx.beginPath(); ctx.arc(this.x, this.y, this.radius, 0, 2 * Math.PI); ctx.fillStyle = "rgba(" + this.color.a + "," + this.color.b + "," + this.color.c + ",1)"; ctx.fill() ctx.restore(); }, moveTo: function (index) { this.ty = this.ty + 0.3; var dx = this.tx - this.x, dy = this.ty - this.y; this.x = Math.abs(dx) < 0.1 ? this.tx : (this.x + dx * 0.1); this.y = Math.abs(dy) < 0.1 ? this.ty : (this.y + dy * 0.1); if (dx === 0 && Math.abs(dy) <= 80) { this.dead = true; } this.paint(); } }

总结

几种不同canvas实现烟花动画，基本分为烟火类和碎屑类展现烟花的不同状态。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。