47 lines
889 B
Plaintext
47 lines
889 B
Plaintext
<!doctype html>
|
|
<html>
|
|
|
|
<head>
|
|
<title>Canvas HTML5</title>
|
|
<style>
|
|
#canvas {
|
|
border: 1px solid black;
|
|
}
|
|
</style>
|
|
</head>
|
|
|
|
<body>
|
|
<div><canvas id="canvas"></canvas></div>
|
|
<script>
|
|
const canvas = document.getElementById("canvas");
|
|
const ctx = canvas.getContext("2d");
|
|
const ballSize = 10;
|
|
let x = canvas.width/2;
|
|
let y = canvas.height/2;
|
|
let dirX = 1;
|
|
let dirY = 1;
|
|
function drawBall() {
|
|
ctx.beginPath();
|
|
ctx.arc(x, y, ballSize, 0, Math.PI*2);
|
|
ctx.fillStyle = "red";
|
|
ctx.fill();
|
|
ctx.closePath();
|
|
}
|
|
function move() {
|
|
ctx.clearRect(0, 0, canvas.width, canvas.height);
|
|
drawBall();
|
|
if(x > canvas.width-ballSize || x < ballSize) {
|
|
dirX *= -1;
|
|
}
|
|
if(y > canvas.height-ballSize || y < ballSize) {
|
|
dirY *= -1;
|
|
}
|
|
x += dirX;
|
|
y += dirY;
|
|
}
|
|
setInterval(move, 10);
|
|
</script>
|
|
</body>
|
|
|
|
</html>
|