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| <!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>canvas colorful ball</title>
<style>
#canvas {
margin: 0 auto;
display: block;
}
</style>
</head>
<body>
<canvas id="canvas">current browser is not support</canvas>
<script>
/*get canvas*/
const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');
canvas.width = 1000;
canvas.height = 600;
canvas.style.backgroundColor = '#000';
/*Ball class*/
class Ball {
constructor(x, y, color) {
this.x = x;
this.y = y;
this.color = color;
this.r = 30;
}
/*render ball*/
render() {
ctx.save();
ctx.beginPath();
ctx.arc(this.x, this.y, this.r, 0, Math.PI * 2);
ctx.fillStyle = this.color;
ctx.fill();
ctx.restore();
}
}
/*move mouse action*/
class MoveBall extends Ball {
constructor(x, y, color) {
super(x, y, color);
this.dX = parseInt(Math.random() * 10 - 5);
this.dY = parseInt(Math.random() * 10 - 5);
this.dR = parseInt(Math.random() * 2 + 1);
}
update() {
this.x += this.dX;
this.y += this.dY;
this.r -= this.dR;
if (this.r < 0) this.r = 0;
}
}
let ballArray = [];
let colorArray = ['red', 'yellow', 'blue', 'purple', 'pink', 'orange'];
canvas.addEventListener('mousemove', function(e) {
var e = e || event;
var colorIndex = parseInt(Math.random() * 5);
ballArray.push(new MoveBall(e.offsetX, e.offsetY, colorArray[colorIndex]));
});
setInterval(function() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
for(item of ballArray) {
item.render();
item.update();
}
}, 50);
</script>
</body>
</html>
|
