Canvas的寬與高

原創

Meskjei

2019-07-03 03:58

Canvas的默認寬高爲寬300px，高150px。

（因爲邊框的原因，寬高都多了2）

先畫一條簡單的線：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <style>
        .canvas{
            border: 1px solid red;
        }
    </style>
    <title>Document</title>
</head>
<body>
    <canvas id='myCanvas' class="canvas"></canvas>
    <script>
        const myCanvas = document.getElementById('myCanvas');
        const ctx = myCanvas.getContext('2d');
        ctx.moveTo(0, 0);
        ctx.lineTo(100, 100);
        ctx.stroke();
    </script>
</body>
</html>