【canvas是什么牌子】canvas实现爱心和彩虹雨效果

效果图：

代码如下：

 

 代码如下

 

 

 

 

 

 

 

 <script>

 var canvas = document.getElementById('canvas'),

 ctx = canvas.getContext('2d'),

 canvasW = canvas.width = window.innerWidth,

 canvasH = canvas.height = window.innerHeight,

 canvasWHalf = canvasW / 2,

 canvasHHalf = canvasH / 2,

 xoff = canvasWHalf - 306,

 yoff = 50,

 bg = '00061a',

 id = 0,

 raindrops = [],

 minSize = 1,

 maxSize = 4,

 minSpeed = 5,

 maxSpeed = 20,

 minHue = 0,

 maxHue = 360,

 maxAmount = 50;

 function random(min, max) {

 if (arguments.length <2) {

  max=min;

  min=0;

 }

 return Math.floor(Math.random() * (max - min) + min);

 }

 function hexToRGB(hex, opacity) {

 varrgb='';

 hex.match(/.{2}/g).forEach(function(n) {

  rgb += (parseInt(n, 16)) + ',';

 });

 return 'rgba(' + rgb + opacity + ')';

 }

 function draw() {

 // Heart

 ctx.fillStyle=hexToRGB(bg, '0.1');

 ctx.beginPath();

 // Left half

 ctx.moveTo(0, 0);

 ctx.lineTo(canvasWHalf, 0);

 ctx.lineTo(304 + xoff, 97 + yoff);

 ctx.bezierCurveTo(282 + xoff, -5 + yoff, 80 + xoff, -6 + yoff, 76 + xoff, 165 + yoff);

 ctx.bezierCurveTo(74 + xoff, 251 + yoff, 184 + xoff, 300 + yoff, 304 + xoff, 447 + yoff);

 ctx.lineTo(canvasWHalf, canvasH);

 ctx.lineTo(0, canvasH);

 // Right half

 ctx.moveTo(canvasW, 0);

 ctx.lineTo(canvasWHalf, 0);

 ctx.lineTo(304 + xoff, 97 + yoff);

 ctx.bezierCurveTo(326 + xoff, 5 + yoff, 528 + xoff, 6 + yoff, 532 + xoff, 165 + yoff);

 ctx.bezierCurveTo(534 + xoff, 251 + yoff, 424 + xoff, 300 + yoff, 304 + xoff, 447 + yoff);

 ctx.lineTo(canvasWHalf, canvasH);

 ctx.lineTo(canvasW, canvasH);

 ctx.closePath();

 ctx.fill();

 // Raindrops

 for (vari=1; i < id; i++) {

  raindrops[i].fall();

 };

 }

 varRaindrop=function() {

 id++;

 this.y=random(-canvasH);

 this.x=random(canvasW);

 this.size=random(minSize, maxSize);

 this.speed=random(minSpeed, maxSpeed);

 this.color='hsl('+ random(minHue, maxHue) + ',100%,55%)';

 this.origColor= this.color;

 this.id= id;

 raindrops[id] = this;

 };

 Raindrop.prototype.fall=function() {

 this.y += this.speed;

 if (this.y >= canvasH) {

  this.y = random(-canvasH);

  this.x = random(canvasW);

 }

 ctx.save();

 ctx.beginPath();

 var gradient = ctx.createRadialGradient(this.x, this.y, 0, this.x, this.y, this.size);

 gradient.addColorStop(0, '#fff');

 gradient.addColorStop(0.5, this.color);

 gradient.addColorStop(1, hexToRGB(bg, 0));

 ctx.rect(this.x, this.y, this.size, maxSpeed);

 ctx.fillStyle = gradient;

 ctx.fill();

 ctx.closePath();

 ctx.restore();

 };

 (function init() {

 ctx.fillStyle = '#' + bg;

 ctx.fillRect(0, 0, canvasW, canvasH);

 for (var i = 0; i

  new Raindrop();

 }

 }());

 function animate() {

 draw();

 window.requestAnimationFrame(animate);

 }

 window.requestAnimationFrame(animate);

 function mouseTrail(x, y) {

 ctx.save();

 ctx.globalCompositeOperation='overlay';

 ctx.fillStyle='rgba(255,255,255,0.1)';

 ctx.arc(x, y, 50, 0, Math.PI * 2);

 ctx.fill();

 ctx.restore();

 }

 window.addEventListener('mousemove', function(cursor) {

 mouseTrail(cursor.x, cursor.y);

 });

 </script>

 

 

【canvas是什么牌子】canvas实现爱心和彩虹雨效果

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