random color and shape generator using canvas, Javascript and the Paper.js library
git clone https://github.com/bgoonz/jsanimate
launch index.html using the vscode live server extension
let can = document.getElementById("canvas");
can.style.width = window.innerWidth + "px";
can.style.height = window.innerHeight + "px";
// Install paper to the global scope
paper.install(window)
paper.setup("canvas")
let rotation = 0;
let pathArray = [];
let grower = false;
let createNewPattern = function (position, step, grower) {
// Create new Circle Path with Paper.js
let path = new Path.Circle({
center: [80, 50],
radius: step,
strokeColor: 'white',
fillColor: 'pink',
grower: grower
});
path.position = position
// Generate random shape movement
path.movementX = Math.round(Math.random()) * 2 - 1;
path.movementY = Math.round(Math.random()) * 2 - 1;
// Store path
pathArray.push(path)
// Rotate shapes
path.rotate(rotation)
// Update position
path.originalPosition = position;
}
// Grow shape while holding mouse down
view.onMouseDown = function (e) {
grower = true;
}
// Stop growing shape when releasing mouse
view.onMouseUp = function (e) {
grower = false;
}
view.onMouseMove = function (e) {
// event.delta describes = vector btwn the current & last pos of the mouse when event fired
if (e.delta) {
// The smaller the number the quicker the growth of the shape pattern (also more circular)
// Interesting note: grow the circle by mousing over on the left side of the screen, crossing across another window as a bridge and entering page again on the right side!
let step = Math.min((e.delta.length / 10), 12);
createNewPattern(e.point, step, grower)
}
}
view.onFrame = function (e) {
pathArray.forEach(function (line, index) {
// Rate of color change. Beware of any # above 20! Photosensitive epilepsy trigger.
line.fillColor.hue += 2;
for (let i = 0; i < line.segments.length; i++) {
let segment = line.segments[i];
// Randomize x and y movement. Comment out for an equally cool pattern that persists for a set time before disappearing
segment.point.x += line.movementX * Math.random();
segment.point.y += line.movementY * Math.random();
}
// Change the y position of the segment point:
line.grower ? line.scale(1.04) : line.scale(0.999);
// Rotate elements in the line
line.rotate(2);
if (!grower) {
line.grower = false;
}
// Clear screen after a limited path or line length
if (pathArray.length > 200 || line.length > 1000) {
line.remove();
pathArray.splice(index, 1);
}
})
}
// Start with demo shapes and sizes
function createDemoShapes() {
for (i = 0; i < 20; i++) {
let maxPoint = new Point(view.size.width, view.size.height);
let randomPoint = Point.random();
let generationPoint = { x: maxPoint.x * randomPoint.x, y: maxPoint.y * randomPoint.y };
// Size of starter shapes
let step = Math.random() * 100;
let grower = Math.random() >= 5;
createNewPattern(generationPoint, step, grower);
}
}
createDemoShapes();<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>CSS Tricks</title>
<link href="./style.css" type="text/css" rel="stylesheet">
</head>
<body>
<canvas id="canvas" resize>
</canvas>
<script src='https://cdnjs.cloudflare.com/ajax/libs/paper.js/0.10.2/paper-full.min.js'></script>
<script src="./circles.js"></script>
</body>
</html>body{
margin:0;
}
#canvas {
display: block;
width: 100%;
background: #0a0a0a;
z-index: 10;
}