哇,這比我預期的更容易,更有趣。以下代碼位於我的HTML代碼的<body>
部分,針對750x80像素的幀進行了優化。隨機整數發生器我從this other question得到。
<canvas id="canvas" width="750" height="80"></canvas>
<script type="text/javascript">
//Random integer generator
function getRandomInt (min, max) {
return Math.floor(Math.random() * (max - min + 1)) + min;
}
function draw() {
var ctx = document.getElementById('canvas').getContext('2d');
//Loop to make 80 squares
for (var i=0;i<80;i++) {
//The x-position of the square, with 5px padding in frame
var sx = getRandomInt(5,705);
//The y-position of the square, with 5px padding in frame
var sy = getRandomInt(5,35);
//The height of the square, smallest 8x8px, largest 40x40px
var sh = getRandomInt(8,40);
//First, create a black square
ctx.fillStyle = "rgb(0,0,0)";
ctx.fillRect (sx, sy, sh, sh);
//Second, create a white square that's 4px shorter and thinner,
//leaving a boundary of 2px
ctx.fillStyle = "rgb(255,255,255)";
ctx.fillRect (sx+2, sy+2, sh-4, sh-4);
}
}
draw();
</script>
我使用的方法是從a Mozilla Developers page。其結果是這樣的:
萬歲!