canvas可以实现不同动画效果，本文主要记录几种不同节日烟花效果实现。

实现一

html

<canvas id="canvas"></canvas>

css

body {    background: #000;    margin: 0;}canvas {    cursor: crosshair;    display: block;}

js

// when animating on canvas, it is best to use requestAnimationFrame instead of setTimeout or setInterval// not supported in all browsers though and sometimes needs a prefix, so we need a shimwindow.requestAnimFrame = (function () {    return window.requestAnimationFrame ||        window.webkitRequestAnimationFrame ||        window.mozRequestAnimationFrame ||        function (callback) {            window.setTimeout(callback, 1000 / 60);        };})();// now we will setup our basic variables for the demovar canvas = document.getElementById(canvas),    ctx = canvas.getContext(2d),    // full screen dimensions    cw = window.innerWidth,    ch = window.innerHeight,    // firework collection    fireworks = [],    // particle collection    particles = [],    // starting hue    hue = 120,    // when launching fireworks with a click, too many get launched at once without a limiter, one launch per 5 loop ticks    limiterTotal = 5,    limiterTick = 0,    // this will time the auto launches of fireworks, one launch per 80 loop ticks    timerTotal = 80,    timerTick = 0,    mousedown = false,    // mouse x coordinate,    mx,    // mouse y coordinate    my;// set canvas dimensionscanvas.width = cw;canvas.height = ch;// now we are going to setup our function placeholders for the entire demo// get a random number within a rangefunction random(min, max) {    return Math.random() * (max - min) + min;}// calculate the distance between two pointsfunction calculateDistance(p1x, p1y, p2x, p2y) {    var xDistance = p1x - p2x,        yDistance = p1y - p2y;    return Math.sqrt(Math.pow(xDistance, 2) + Math.pow(yDistance, 2));}// create fireworkfunction Firework(sx, sy, tx, ty) {    // actual coordinates    this.x = sx;    this.y = sy;    // starting coordinates    this.sx = sx;    this.sy = sy;    // target coordinates    this.tx = tx;    this.ty = ty;    // distance from starting point to target    this.distanceToTarget = calculateDistance(sx, sy, tx, ty);    this.distanceTraveled = 0;    // track the past coordinates of each firework to create a trail effect, increase the coordinate count to create more prominent trails    this.coordinates = [];    this.coordinateCount = 3;    // populate initial coordinate collection with the current coordinates    while (this.coordinateCount--) {        this.coordinates.push([this.x, this.y]);    }    this.angle = Math.atan2(ty - sy, tx - sx);    this.speed = 2;    this.acceleration = 1.05;    this.brightness = random(50, 70);    // circle target indicator radius    this.targetRadius = 1;}// update fireworkFirework.prototype.update = function (index) {    // remove last item in coordinates array    this.coordinates.pop();    // add current coordinates to the start of the array    this.coordinates.unshift([this.x, this.y]);    // cycle the circle target indicator radius    if (this.targetRadius < 8) {        this.targetRadius += 0.3;    } else {        this.targetRadius = 1;    }    // speed up the firework    this.speed *= this.acceleration;    // get the current velocities based on angle and speed    var vx = Math.cos(this.angle) * this.speed,        vy = Math.sin(this.angle) * this.speed;    // how far will the firework have traveled with velocities applied?    this.distanceTraveled = calculateDistance(this.sx, this.sy, this.x + vx, this.y + vy);    // if the distance traveled, including velocities, is greater than the initial distance to the target, then the target has been reached    if (this.distanceTraveled >= this.distanceToTarget) {        createParticles(this.tx, this.ty);        // remove the firework, use the index passed into the update function to determine which to remove        fireworks.splice(index, 1);    } else {        // target not reached, keep traveling        this.x += vx;        this.y += vy;    }}// draw fireworkFirework.prototype.draw = function () {    ctx.beginPath();    // move to the last tracked coordinate in the set, then draw a line to the current x and y    ctx.moveTo(this.coordinates[this.coordinates.length - 1][0], this.coordinates[this.coordinates.length - 1][        1    ]);    ctx.lineTo(this.x, this.y);    ctx.strokeStyle = hsl( + hue + , 100%,  + this.brightness + %);    ctx.stroke();    ctx.beginPath();    // draw the target for this firework with a pulsing circle    ctx.arc(this.tx, this.ty, this.targetRadius, 0, Math.PI * 2);    ctx.stroke();}// create particlefunction Particle(x, y) {    this.x = x;    this.y = y;    // track the past coordinates of each particle to create a trail effect, increase the coordinate count to create more prominent trails    this.coordinates = [];    this.coordinateCount = 5;    while (this.coordinateCount--) {        this.coordinates.push([this.x, this.y]);    }    // set a random angle in all possible directions, in radians    this.angle = random(0, Math.PI * 2);    this.speed = random(1, 10);    // friction will slow the particle down    this.friction = 0.95;    // gravity will be applied and pull the particle down    this.gravity = 1;    // set the hue to a random number +-20 of the overall hue variable    this.hue = random(hue - 20, hue + 20);    this.brightness = random(50, 80);    this.alpha = 1;    // set how fast the particle fades out    this.decay = random(0.015, 0.03);}// update particleParticle.prototype.update = function (index) {    // remove last item in coordinates array    this.coordinates.pop();    // add current coordinates to the start of the array    this.coordinates.unshift([this.x, this.y]);    // slow down the particle    this.speed *= this.friction;    // apply velocity    this.x += Math.cos(this.angle) * this.speed;    this.y += Math.sin(this.angle) * this.speed + this.gravity;    // fade out the particle    this.alpha -= this.decay;    // remove the particle once the alpha is low enough, based on the passed in index    if (this.alpha <= this.decay) {        particles.splice(index, 1);    }} // draw particleParticle.prototype.draw = function () {    ctx.beginPath();    // move to the last tracked coordinates in the set, then draw a line to the current x and y    ctx.moveTo(this.coordinates[this.coordinates.length - 1][0], this.coordinates[this.coordinates.length - 1][        1    ]);    ctx.lineTo(this.x, this.y);    ctx.strokeStyle = hsla( + this.hue + , 100%,  + this.brightness + %,  + this.alpha + );    ctx.stroke();}// create particle group/explosionfunction createParticles(x, y) {    // increase the particle count for a bigger explosion, beware of the canvas performance hit with the increased particles though    var particleCount = 30;    while (particleCount--) {        particles.push(new Particle(x, y));    }}// main demo loopfunction loop() {    // this function will run endlessly with requestAnimationFrame    requestAnimFrame(loop);    // increase the hue to get different colored fireworks over time    hue += 0.5;    // normally, clearRect() would be used to clear the canvas    // we want to create a trailing effect though    // setting the composite operation to destination-out will allow us to clear the canvas at a specific opacity, rather than wiping it entirely    ctx.globalCompositeOperation = destination-out;    // decrease the alpha property to create more prominent trails    ctx.fillStyle = rgba(0, 0, 0, 0.5);    ctx.fillRect(0, 0, cw, ch);    // change the composite operation back to our main mode    // lighter creates bright highlight points as the fireworks and particles overlap each other    ctx.globalCompositeOperation = lighter;    var text = "HAPPY NEW YEAR !";    ctx.font = "50px sans-serif";    var textData = ctx.measureText(text);    ctx.fillStyle = "rgba(" + parseInt(random(0, 255)) + "," + parseInt(random(0, 255)) + "," + parseInt(random(0,        255)) + ",0.3)";    ctx.fillText(text, cw / 2 - textData.width / 2, ch / 2);    // loop over each firework, draw it, update it    var i = fireworks.length;    while (i--) {        fireworks[i].draw();        fireworks[i].update(i);    }    // loop over each particle, draw it, update it    var i = particles.length;    while (i--) {        particles[i].draw();        particles[i].update(i);    }    // launch fireworks automatically to random coordinates, when the mouse isnt down    if (timerTick >= timerTotal) {        if (!mousedown) {            // start the firework at the bottom middle of the screen, then set the random target coordinates, the random y coordinates will be set within the range of the top half of the screen            for (var h = 0; h < 50; h++) {                fireworks.push(new Firework(cw / 2, ch / 2, random(0, cw), random(0, ch)));            }            timerTick = 0;        }    } else {        timerTick++;    }    // limit the rate at which fireworks get launched when mouse is down    if (limiterTick >= limiterTotal) {        if (mousedown) {            // start the firework at the bottom middle of the screen, then set the current mouse coordinates as the target            fireworks.push(new Firework(cw / 2, ch / 2, mx, my));            limiterTick = 0;        }    } else {        limiterTick++;    }}// mouse event bindings// update the mouse coordinates on mousemovecanvas.addEventListener(mousemove, function (e) {    mx = e.pageX - canvas.offsetLeft;    my = e.pageY - canvas.offsetTop;});// toggle mousedown state and prevent canvas from being selectedcanvas.addEventListener(mousedown, function (e) {    e.preventDefault();    mousedown = true;});canvas.addEventListener(mouseup, function (e) {    e.preventDefault();    mousedown = false;});// once the window loads, we are ready for some fireworks!window.onload = loop;

实现二

html

<canvas></canvas><h1>201<span>8</span></h1>

css

html,body {    padding: 0px;    margin: 0px;    background: #222;    font-family: Karla, sans-serif;    color: #FFF;    height: 100%;    overflow: hidden;}h1 {    z-index: 1000;    position: fixed;    top: 50%;    left: 50%;    transform: translateX(-50%) translateY(-100%);    font-size: 58px;    overflow: hidden;}span {    position: relative;    display: inline-block;    animation: drop 0.75s ease 0s;}canvas {    width: 100%;    height: 100%;}@keyframes drop {    0% {        transform: translateY(-100px);        opacity: 0;    }    90% {        opacity: 1;        transform: translateY(10px);    }    100% {        transform: translateY(0px);    }}

js

var ctx = document.querySelector(canvas).getContext(2d)ctx.canvas.width = window.innerWidthctx.canvas.height = window.innerHeightvar 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。