Canvas有两种类型的调整行为：

Canvas has two types of resize behavior:

• 调整内容在画布增长或缩小时保持静态的大小

这里有一个页面演示了两种类型的调整大小： http://xavi.co/static/so-resizable-canvas.html

Here's a page that demonstrates the two types of "resizing": http://xavi.co/static/so-resizable-canvas.html

如果您需要第一种类型调整大小（拉伸内容），然后将画布放入一个容器 div ，并设置 width 和 height 设置为100％。代码如下所示：

If you want the first type of resizing (stretch the content) then place the canvas into a container div and set the width and height of the canvas to 100% using CSS. Here's what that code might look like:

/* The CSS */
#stretch {
    height: 100px;
    width: 200px;
}

#stretch canvas {
    width: 100%;
    height: 100%;
}

<!-- The markup -->
<div id="stretch"><canvas></canvas></div>

// The JavaScript
$("#stretch").resizable();

第二种调整大小（静态内容）的过程分为两步。首先必须调整canvas元素的 width 和 height 属性。不幸的是，这样做会清除画布，因此您必须重新绘制其所有内容。这里有一些代码：

The second type of resizing (static content) is a two step process. First you must adjust the width and height attributes of the canvas element. Unfortunately, doing this clears the canvas, so you must then re-draw all its contents. Here's bit of code that does this:

/* The CSS */
#resize {
    height: 100px;
    width: 200px;
}

<!-- The markup -->
<div id="resize"><canvas></canvas></div>

// The JavaScript
$("#resize").resizable({ stop: function(event, ui) {
    $("canvas", this).each(function() { 
        $(this).attr({ width: ui.size.width, height: ui.size.height });

        // Adjusting the width or height attribute clears the canvas of
        // its contents, so you are forced to redraw.
        reDraw(this);
    });
} });

目前上述代码在用户停止调整窗口小部件时重新绘制画布的内容。可以在调整大小上重新绘制画布，但调整大小的事件会相当正常经常和重复是昂贵的操作 - 谨慎的方法。

Currently the code above re-draws the canvas's content when the user stops resizing the widget. It's possible to re-draw the canvas on resize, however resize events occur fairly often and re-draws are expensive operations -- approach with caution.