<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
<style>
@import url(https://fonts.googleapis.com/css?family=Poiret+One);
html {
overflow: hidden;
touch-action: none;
content-zooming: none;
}
body {
position: absolute;
margin: 0;
padding: 0;
background: #111;
width: 100%;
height: 100%;
}
#canvas {
width: 100%;
height: 100%;
background: #fff;
position: absolute;
}
#text {
position:absolute;
left:0;
bottom:10px;
width:100%;
pointer-events: none;
}
#text div {
position:absolute;
color:#888;
left:0;
width:100%;
text-align:center;
top:-32px;
font-family: 'Poiret One', cursive;
font-size:32px;
}
</style>
</HEAD>
<BODY>
<canvas id="canvas"></canvas>
<div id="text">
<div id="clic" nowrap>this pen is mouse/touch interactive</div>
</div>
<script>
! function () {
"use strict";
// branch constructor
function Branch (parent, level, x, y) {
this.parent = parent;
this.branches = [];
this.p0 = parent ? parent.p1 : new Point(x, y);
this.p1 = new Point(x, y);
this.level = level;
this.life = 20;
this.angle = 0;
this.vx = 0;
this.vy = 0;
}
// grow branch
Branch.prototype.grow = function () {
// recursively grow children branches
for (var i = 0; i < this.branches.length; i++) {
this.branches[i].grow();
}
// grow branch
if (this.life > 1) {
this.p1.x += this.vx;
this.p1.y += this.vy;
ctx.beginPath();
ctx.lineCap = "round";
if (this.level) {
// draw branch
ctx.lineWidth = this.level * 6 - 5;
ctx.strokeStyle = "#000";
if (this.parent) {
ctx.moveTo(this.parent.p0.x, this.parent.p0.y);
ctx.quadraticCurveTo(this.p0.x, this.p0.y, this.p1.x, this.p1.y);
}
ctx.stroke();
} else {
// draw leaf
ctx.lineWidth = 10;
ctx.strokeStyle = "#f40";
ctx.moveTo(this.p0.x, this.p0.y);
ctx.lineTo(this.p1.x, this.p1.y);
ctx.stroke();
}
}
// create sub branches
if (this.life === 1 && this.level > 0 && this.level < maxLevels) {
this.branches.push(newBranch(this));
this.branches.push(newBranch(this));
}
// decrement branch life
this.life--;
}
// point 2D constructor
function Point (x, y) {
this.x = x;
this.y = y;
}
// new branch factory
function newBranch (parent) {
var branch = new Branch (parent, parent.level - 1, parent.p1.x, parent.p1.y);
branch.angle = (autorun && parent.level === maxLevels) ? Math.random() * 2 * Math.PI : Math.atan2(
parent.p1.y - parent.p0.y,
parent.p1.x - parent.p0.x
) + (Math.random() * 1.4 - 0.7);
branch.vx = Math.cos(branch.angle) * 12;
branch.vy = Math.sin(branch.angle) * 12;
branch.life = branch.level === 1 ? 5 : Math.round(Math.random() * (branch.level * 2)) + 2;
return branch;
}
// main animation loop
function run () {
// request next frame
requestAnimationFrame(run);
// clear screen (with a bit of magic)
if (++frame % 2) {
ctx.globalCompositeOperation = "lighter";
ctx.fillStyle = "rgba(255,255,255,0.01)";
ctx.fillRect(0, 0, canvas.width, canvas.height);
ctx.globalCompositeOperation = "source-over";
}
// follow the pointer
current.p1.x = pointer.x;
current.p1.y = pointer.y;
// grow tree
root.grow();
// create trunk branches
if ((autorun && Math.random() > 0.8) || pointer.moveDistance > 20) {
pointer.moveDistance = 0;
var branch = new Branch (current, current.level, current.p1.x, current.p1.y);
current.branches.push(branch);
if (Math.random() > 0.8) current.branches.push(newBranch(current));
current = branch;
nBranches++;
}
// cut the tree
if (nBranches > maxBranches) {
root = root.branches[0];
nBranches--;
}
}
// prepare the canvas
var canvas = {
elem: document.getElementById('canvas'),
width: 0,
height: 0,
resize: function () {
this.width = this.elem.width = this.elem.offsetWidth;
this.height = this.elem.height = this.elem.offsetHeight;
}
}
var ctx = canvas.elem.getContext("2d");
canvas.elem.onselectstart = function() { return false; }
canvas.elem.ondragstart = function() { return false; }
window.addEventListener('resize', canvas.resize.bind(canvas), false);
canvas.resize();
// pointer events
var pointer = {
x: canvas.width * 0.5,
y: canvas.height * 0.5,
px: 0,
py: 0,
moveDistance: 0,
move: function (e) {
e.preventDefault();
var pointer = e.targetTouches ? e.targetTouches[0] : e;
this.x = pointer.clientX;
this.y = pointer.clientY;
var dx = this.x - this.px;
var dy = this.y - this.py;
this.moveDistance += Math.sqrt(dx * dx + dy * dy);
// speed limit
if (this.moveDistance > 40) {
this.x = this.px + dx * 0.1;
this.y = this.py + dy * 0.1;
}
// cancel autorun
if (autorun) {
this.x = pointer.clientX;
this.y = pointer.clientY;
root = new Branch (false, maxLevels, this.x, this.y);
current = root;
autorun = false;
document.getElementById("clic").innerHTML = "";
}
this.px = this.x;
this.py = this.y;
}
}
window.addEventListener("mousemove", pointer.move.bind(pointer), false );
canvas.elem.addEventListener("touchmove", pointer.move.bind(pointer), false );
// variables
var maxLevels = 7;
var nBranches = 0;
var maxBranches = 200;
var autorun = true;
var frame = 0;
var root = new Branch (false, maxLevels, pointer.x, pointer.y);
var current = root;
// start
run();
}();
</script>
</BODY>
</HTML>
