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<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>HTML5 Canvas粒子汇聚文字动画特效</title>
<style>
body {
padding: 0px;
margin: 0px;
background-color: #252525;
}
.hidden {
display: none;
}
#spring-text {
position: absolute;
}
</style>
</head>
<body>
<!-- 尝试移动鼠标并单击文本区域 -->
<div id="title-desktop" class="hidden">粒子字体效果</div>
<div id="title-mobile" class="hidden">Chinaz</div>
<canvas id="spring-text"></canvas>
<script>
// WRITTEN BY TRUMAN HEBERLE
var COLOR = "#52E6FF"
var MESSAGE = document.getElementById("title-desktop").textContent;
var FONT_SIZE = 50;
var AMOUNT = 8000;
var SIZE = 1;
var INITIAL_DISPLACEMENT = 100;
var INITIAL_VELOCITY = 3;
var VELOCITY_RETENTION = 0.95;
var SETTLE_SPEED = 1;
var FLEE_SPEED = 1;
var FLEE_DISTANCE = 20;
var FLEE = true;
var SCATTER_VELOCITY = 3;
var SCATTER = true;
const canvas = document.getElementById("spring-text");
let canvasWidth = 600;
let canvasHeight = 80;
const ctx = canvas.getContext("2d");
var POINTS = [];
var MOUSE = {
x: 0,
y: 0
}
function Point(x,y,r,g,b,a) {
var angle = Math.random() * 6.28;
this.dest_x = x;
this.dest_y = y;
this.original_r = r;
this.original_g = g;
this.original_a = a;
this.x = canvas.width/2 - x + (Math.random() - 0.5) * INITIAL_DISPLACEMENT;
this.y = canvas.height/2 - y + (Math.random() - 0.5) * INITIAL_DISPLACEMENT;
this.velx = INITIAL_VELOCITY * Math.cos(angle);
this.vely = INITIAL_VELOCITY * Math.sin(angle);
this.target_x = canvas.width/2 - x;
this.target_y = canvas.height/2 - y;
this.r = r;
this.g = g;
this.b = b;
this.a = a;
this.getX = function() {
return this.x;
}
this.getY = function() {
return this.y;
}
this.resetTarget = function () {
this.target_x = canvas.width/2 - this.dest_x;
this.target_y = canvas.height/2 - this.dest_y;
}
this.fleeFrom = function(x, y) {
this.velx -= ((MOUSE.x - this.x) * FLEE_SPEED / 10);
this.vely -= ((MOUSE.y - this.y) * FLEE_SPEED / 10);
}
this.settleTo = function(x, y) {
this.velx += ((this.target_x - this.x) * SETTLE_SPEED / 100);
this.vely += ((this.target_y - this.y) * SETTLE_SPEED / 100);
this.velx -= this.velx * (1-VELOCITY_RETENTION);
this.vely -= this.vely * (1-VELOCITY_RETENTION);
}
this.scatter = function() {
var unit = this.unitVecToMouse();
var vel = SCATTER_VELOCITY * 10 * (0.5 + Math.random() / 2);
this.velx = -unit.x * vel;
this.vely = -unit.y * vel;
}
this.move = function() {
if (this.distanceToMouse() <= FLEE_DISTANCE) {
this.fleeFrom(MOUSE.x, MOUSE.y);
}
else {
this.settleTo(this.target_x, this.target_y);
}
if (this.x + this.velx < 0 || this.x + this.velx >= canvas.width) {
this.velx *= -1;
}
if (this.y + this.vely < 0 || this.y + this.vely >= canvas.height) {
this.vely *= -1;
}
this.x += this.velx;
this.y += this.vely;
}
this.distanceToTarget = function() {
return this.distanceTo(this.target_x, this.target_y);
}
this.distanceToMouse = function() {
return this.distanceTo(MOUSE.x, MOUSE.y);
}
this.distanceTo = function(x, y) {
return Math.sqrt((x - this.x)*(x - this.x) + (y - this.y)*(y - this.y));
}
this.unitVecToTarget = function() {
return this.unitVecTo(this.target_x, this.target_y);
}
this.unitVecToMouse = function() {
return this.unitVecTo(MOUSE.x, MOUSE.y);
}
this.unitVecTo = function(x, y) {
var dx = x - this.x;
var dy = y - this.y;
return {
x: dx / Math.sqrt(dx*dx + dy*dy),
y: dy / Math.sqrt(dx*dx + dy*dy)
};
}
}
if (FLEE) {
window.addEventListener("mousemove", function(event) {
MOUSE.x = event.clientX;
MOUSE.y = event.clientY;
});
}
if (SCATTER) {
window.addEventListener("click", function(event) {
MOUSE.x = event.clientX;
MOUSE.y = event.clientY;
for (var i=0; i<POINTS.length; i++) {
POINTS[i].scatter();
}
});
}
function initCanvas() {
canvas.width = canvasWidth;
canvas.height = canvasHeight;
}
function adjustText() {
ctx.fillStyle = COLOR;
ctx.textBaseline = "middle";
ctx.textAlign = "center";
ctx.font = FONT_SIZE + "px Arial";
ctx.fillText(MESSAGE, canvas.width/2, canvas.height/2);
var textWidth = ctx.measureText(MESSAGE).width;
if (textWidth == 0) {
return;
}
var minX = canvas.width/2 - textWidth/2;
var minY = canvas.height/2 - FONT_SIZE/2;
var data = ctx.getImageData(minX, minY, textWidth, FONT_SIZE).data;
var isBlank = true;
for (var i=0; i<data.length; i++) {
if (data[i] != 0) {
isBlank = false;
break;
}
}
if (!isBlank) {
var count = 0;
var curr = 0;
var num = 0;
var x = 0;
var y = 0;
var w = Math.floor(textWidth);
POINTS = [];
while (count < AMOUNT) {
while (curr == 0) {
num = Math.floor(Math.random() * data.length);
curr = data[num];
}
num = Math.floor(num / 4);
x = w/2 - num%w;
y = FONT_SIZE/2 - Math.floor(num/w);
POINTS.push(new Point(x,y,data[num*4],data[num*4 + 1],data[num*4 + 2],data[num*4 + 3]));
curr = 0;
count++;
}
}
}
function init() {
initCanvas()
adjustText()
window.requestAnimationFrame(animate);
}
function animate() {
update();
draw();
}
function update() {
var point;
for (var i=0; i<POINTS.length; i++) {
point = POINTS[i];
point.move();
}
}
function draw() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
var point;
for (var i=0; i<POINTS.length; i++) {
point = POINTS[i];
ctx.fillStyle = "rgba("+point.r+","+point.g+","+point.b+","+point.a+")";
ctx.beginPath();
ctx.arc(point.getX(),point.getY(),SIZE,0,2*Math.PI);
ctx.fill();
}
window.requestAnimationFrame(animate);
}
init();
</script>
</body>
</html>
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