# JS 实现烟花特效
# 快速导航
# 实例效果
# 实例代码
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<template>
<div class="wrapper">
<canvas id="canvas">Canvas is not supported in your browser.</canvas>
</div>
</template>
<script>
// 烟花特效
export default {
name: "fireWorkEffect",
data() {
return {
}
},
mounted() {
this.drawCanvas();
},
methods: {
drawCanvas() {
window.requestAnimFrame = (function() { return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || function(callback) { window.setTimeout(callback, 1000 / 60) } })();
var canvas = document.getElementById("canvas"),
ctx = canvas.getContext("2d"),
cw = window.innerWidth,
ch = window.innerHeight,
fireworks = [],
particles = [],
hue = 120,
limiterTotal = 5,
limiterTick = 0,
timerTotal = 80,
timerTick = 0,
mousedown = false,
mx, my;
canvas.width = cw;
canvas.height = ch;
function random(min, max) { return Math.random() * (max - min) + min }
function calculateDistance(p1x, p1y, p2x, p2y) { var xDistance = p1x - p2x,
yDistance = p1y - p2y; return Math.sqrt(Math.pow(xDistance, 2) + Math.pow(yDistance, 2)) }
function Firework(sx, sy, tx, ty) { this.x = sx;
this.y = sy;
this.sx = sx;
this.sy = sy;
this.tx = tx;
this.ty = ty;
this.distanceToTarget = calculateDistance(sx, sy, tx, ty);
this.distanceTraveled = 0;
this.coordinates = [];
this.coordinateCount = 3; 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);
this.targetRadius = 1 } Firework.prototype.update = function(index) { this.coordinates.pop();
this.coordinates.unshift([this.x, this.y]); if (this.targetRadius < 8) { this.targetRadius += 0.3 } else { this.targetRadius = 1 } this.speed *= this.acceleration; var vx = Math.cos(this.angle) * this.speed,
vy = Math.sin(this.angle) * this.speed;
this.distanceTraveled = calculateDistance(this.sx, this.sy, this.x + vx, this.y + vy); if (this.distanceTraveled >= this.distanceToTarget) { createParticles(this.tx, this.ty);
fireworks.splice(index, 1) } else { this.x += vx;
this.y += vy } };
Firework.prototype.draw = function() { ctx.beginPath();
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();
ctx.arc(this.tx, this.ty, this.targetRadius, 0, Math.PI * 2);
ctx.stroke() };
function Particle(x, y) { this.x = x;
this.y = y;
this.coordinates = [];
this.coordinateCount = 5;
while (this.coordinateCount--) { this.coordinates.push([this.x, this.y]) } this.angle = random(0, Math.PI * 2);
this.speed = random(1, 10);
this.friction = 0.95;
this.gravity = 1;
this.hue = random(hue - 20, hue + 20);
this.brightness = random(50, 80);
this.alpha = 1;
this.decay = random(0.015, 0.03) }
Particle.prototype.update = function(index) { this.coordinates.pop();
this.coordinates.unshift([this.x, this.y]);
this.speed *= this.friction;
this.x += Math.cos(this.angle) * this.speed;
this.y += Math.sin(this.angle) * this.speed + this.gravity;
this.alpha -= this.decay; if (this.alpha <= this.decay) { particles.splice(index, 1) } };
Particle.prototype.draw = function() { ctx.beginPath();
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() };
function createParticles(x, y) { var particleCount = 30; while (particleCount--) { particles.push(new Particle(x, y)) } }
function loop() { requestAnimFrame(loop);
hue += 0.5;
ctx.globalCompositeOperation = "destination-out";
ctx.fillStyle = "rgba(0, 0, 0, 0.5)";
ctx.fillRect(0, 0, cw, ch);
ctx.globalCompositeOperation = "lighter";
var i = fireworks.length; while (i--) { fireworks[i].draw();
fireworks[i].update(i) } var i = particles.length; while (i--) { particles[i].draw();
particles[i].update(i) } if (timerTick >= timerTotal) { if (!mousedown) { fireworks.push(new Firework(cw / 2, ch, random(0, cw), random(0, ch / 2)));
timerTick = 0 } } else { timerTick++ } if (limiterTick >= limiterTotal) { if (mousedown) { fireworks.push(new Firework(cw / 2, ch, mx, my));
limiterTick = 0 } } else { limiterTick++ } }
canvas.addEventListener("mousemove", function(e) { mx = e.pageX - canvas.offsetLeft;
my = e.pageY - canvas.offsetTop });
canvas.addEventListener("mousedown", function(e) { e.preventDefault();
mousedown = true });
canvas.addEventListener("mouseup", function(e) { e.preventDefault();
mousedown = false });
window.onload = loop;
}
},
}
</script>
<style lang="scss" scoped>
.wrapper {
background: #000;
margin: 0;
}
canvas {
cursor: crosshair;
display: block;
}
</style>
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