Draw text to & lt; canvas & gt; with @ font-face does not work the first time

When I draw a text in a canvas with a typeface that is loaded via @font-face, the text doesn't show correctly. It doesn't show at all (in Chrome 13 and Firefox 5), or the typeface is wrong (Opera 11). This type of unexpected behavior occurs only at the first drawing with the typeface. After then everything works fine.

Is it the standard behavior or something?

Thank you.

PS: Following is the source code of the test case

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>@font-face and &lt;canvas&gt;</title>
        <style id="css">
@font-face {
    font-family: 'Press Start 2P';
    src: url('fonts/PressStart2P.ttf');
}
        </style>
        <style>
canvas, pre {
    border: 1px solid black;
    padding: 0 1em;
}
        </style>
    </head>
    <body>
        <h1>@font-face and &lt;canvas&gt;</h1>
        <p>
            Description: click the button several times, and you will see the problem.
            The first line won't show at all, or with a wrong typeface even if it does.
            <strong>If you have visited this page before, you may have to refresh (or reload) it.</strong>
        </p>
        <p>
            <button id="draw">#draw</button>
        </p>
        <p>
            <canvas width="250" height="250">
                Your browser does not support the CANVAS element.
                Try the latest Firefox, Google Chrome, Safari or Opera.
            </canvas>
        </p>
        <h2>@font-face</h2>
        <pre id="view-css"></pre>
        <h2>Script</h2>
        <pre id="view-script"></pre>
        <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
        <script id="script">
var x = 30,
    y = 10;

$('#draw').click(function () {
    var canvas = $('canvas')[0],
        ctx = canvas.getContext('2d');
    ctx.font = '12px "Press Start 2P"';
    ctx.fillStyle = '#000';
    ctx.fillText('Hello, world!', x, y += 20);
    ctx.fillRect(x - 20, y - 10, 10, 10);
});
        </script>
        <script>
$('#view-css').text($('#css').text());
$('#view-script').text($('#script').text());
        </script>
    </body>
</html>

Drawing on canvas has to happen and return immediately when you call the fillText method. However, the browser has not yet loaded the font from the network, which is a background task. So it has to fall back to the font it does have available.

If you want to make sure the font is available, have some other element on the page preload it, eg.:

<div style="font-family: PressStart;">.</div>

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