JS特效第158弹：情人节爱心气球告白动画特效_js表白特效

作者：繁依Fanyi0 | 2024-07-23 18:02:19

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js表白特效

html5基于canvas绘制爱心气球挂着文字缓缓上升，情人节气球告白背景动画特效，先来看看效果：

一部分关键的代码如下：


<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>情人节快乐:)</title>
 
<style>
canvas {
	position: absolute;
	top: 0;
	left: 0;
}</style>
</head>
<body>
<canvas id=c></canvas>
 
<script>
var w = c.width = window.innerWidth,
		h = c.height = window.innerHeight,
		ctx = c.getContext( '2d' ),
		
		opts = {
			phrases: [ "我爱你", "你是最棒的！", "你真可爱！", "愿长长久久", "希望你每天开心快乐！", "我爱你的心是直到世界末日也不变", "我不需要分清东西南北，反正我会走向有你的那边", "想想和我一同看日升日落的喜悦吧！", "每天我的动力就是见到你，并和你说说话", "世界一般，但你超值" ],
			balloons: 10,
			baseVelY: -1,
			addedVelY: -1,
			baseVelX: -.25,
			addedVelX: .5,
			baseSize: 20,
			addedSize: 10,
			baseSizeAdder: 2,
			addedSizeAdder: 2,
			baseIncrementer: .01,
			addedIncrementer: .03,
			baseHue: -10,
			addedHue: 30,
			font: '15px Verdana'
		},
		
		cycle = 0,
		balloons = [];
 
ctx.font = opts.font;
 
function Balloon(){
	this.reset();
}
Balloon.prototype.reset = function(){
	
	this.size = opts.baseSize + opts.addedSize * Math.random();
	this.sizeAdder = opts.baseSizeAdder + opts.addedSizeAdder * Math.random();
	this.incrementer = opts.baseIncrementer + opts.addedIncrementer * Math.random();
	
	this.tick = 0;
	
	this.x = Math.random() * w;
	this.y = h + this.size;
	
	this.vx = opts.baseVelX + opts.addedVelX * Math.random();
	this.vy = opts.baseVelY + opts.addedVelY * Math.random();
	
	this.color = 'hsla(hue,70%,60%,.8)'.replace( 'hue', opts.baseHue + opts.addedHue * Math.random() );
	this.phrase = opts.phrases[ ++cycle % opts.phrases.length ].split( '\n' );
	this.lengths = [];
	
	for( var i = 0; i < this.phrase.length; ++i )
		this.lengths.push( -ctx.measureText( this.phrase[ i ] ).width / 2 );
}
Balloon.prototype.step = function(){
	
	this.tick += this.incrementer;
	this.x += this.vx;
	this.y += this.vy;
	
	var size = this.size + this.sizeAdder * Math.sin( this.tick );
	
	ctx.lineWidth = size / 40;
	ctx.strokeStyle = '#eee';
	ctx.beginPath();
	ctx.moveTo( this.x, this.y - 2 );
	ctx.lineTo( this.x, this.y + size );
	ctx.stroke();
	ctx.fillStyle = this.color;
	
	ctx.translate( this.x, this.y );
	ctx.rotate( Math.PI / 4 );
	//ctx.fillRect( -size / 2, -size / 2, size / 2, size / 2 );
	ctx.beginPath();
	ctx.moveTo( 0, 0 );
	ctx.arc( -size / 2, -size / 2 + size / 4, size / 4, Math.PI / 2, Math.PI * 3 / 2 );
	ctx.arc( -size / 2 + size / 4, -size / 2, size / 4, Math.PI, Math.PI * 2 );
	ctx.lineTo( 0, 0 );
	ctx.fill();
	ctx.rotate( -Math.PI / 4 );
	ctx.translate( -this.x, -this.y );
	
	ctx.translate( this.x, this.y + size + 15 );
	ctx.scale( size / this.size, size / this.size );
	ctx.fillStyle = '#eee';
	for( var i = 0; i < this.phrase.length; ++i )
		ctx.fillText( this.phrase[ i ], this.lengths[ i ], i * 15 );
	ctx.scale( this.size / size, this.size / size );
	ctx.translate( -this.x, -( this.y + size + 15 ) );
	
	if( this.y < -size * 3 )
		this.reset();
	
}
 
function anim(){
	
	window.requestAnimationFrame( anim );
	
	ctx.fillStyle = '#222';
	ctx.fillRect( 0, 0, w, h );
	
	if( balloons.length < opts.balloons && Math.random() < .01 )
		balloons.push( new Balloon );
	
	for( var i = 0; i < balloons.length; ++i )
		balloons[ i ].step();
}
anim();</script>
 
</body>
</html>

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