我使用的是sketch.js，所以在我为画布运行init命令后，我用jquery改变宽度和高度。它将维度基于父元素。

$ (' # DrawCanvas ') .sketch () .attr(“高度”,$ (' # DrawCanvas ') .parent () .height ()) .attr(“宽度”,$ (' # DrawCanvas ') .parent () .width ());

下面的解决方案对我来说效果最好。因为我对编码相对陌生，所以我喜欢用视觉来确认某些东西是否按照我期望的方式工作。我在以下地点找到了它: http://htmlcheats.com/html/resize-the-html5-canvas-dyamically/

代码如下:

(function() { var // Obtain a reference to the canvas element using its id. htmlCanvas = document.getElementById('c'), // Obtain a graphics context on the canvas element for drawing. context = htmlCanvas.getContext('2d'); // Start listening to resize events and draw canvas. initialize(); function initialize() { // Register an event listener to call the resizeCanvas() function // each time the window is resized. window.addEventListener('resize', resizeCanvas, false); // Draw canvas border for the first time. resizeCanvas(); } // Display custom canvas. In this case it's a blue, 5 pixel // border that resizes along with the browser window. function redraw() { context.strokeStyle = 'blue'; context.lineWidth = '5'; context.strokeRect(0, 0, window.innerWidth, window.innerHeight); } // Runs each time the DOM window resize event fires. // Resets the canvas dimensions to match window, // then draws the new borders accordingly. function resizeCanvas() { htmlCanvas.width = window.innerWidth; htmlCanvas.height = window.innerHeight; redraw(); } })(); html, body { width: 100%; height: 100%; margin: 0px; border: 0; overflow: hidden; /* Disable scrollbars */ display: block; /* No floating content on sides */ } <canvas id='c' style='position:absolute; left:0px; top:0px;'></canvas>

蓝色边框显示了调整画布的边缘，并且总是沿着窗口的边缘，在所有4个面都可见，这不是上述其他一些答案的情况。希望能有所帮助。

如果你对保留纵横比感兴趣，并在纯CSS中这样做(给定纵横比)，你可以像下面这样做。关键字是::content元素上的padding-bottom，用于调整容器元素的大小。这是相对于它的父类宽度的大小，默认为100%。此处指定的比率必须与canvas元素上的大小比率相匹配。

// Javascript var canvas = document.querySelector('canvas'), context = canvas.getContext('2d'); context.fillStyle = '#ff0000'; context.fillRect(500, 200, 200, 200); context.fillStyle = '#000000'; context.font = '30px serif'; context.fillText('This is some text that should not be distorted, just scaled', 10, 40); /*CSS*/ .container { position: relative; background-color: green; } .container::after { content: ' '; display: block; padding: 0 0 50%; } .wrapper { position: absolute; top: 0; right: 0; left: 0; bottom: 0; } canvas { width: 100%; height: 100%; } <!-- HTML --> <div class=container> <div class=wrapper> <canvas width=1200 height=600></canvas> </div> </div>

下面是一个小而完整的代码片段，它结合了所有的答案。按:“运行代码片段”，然后按“完整页面”，调整窗口大小，以查看其运行情况:

function refresh(referenceWidth, referenceHeight, drawFunction) { const myCanvas = document.getElementById("myCanvas"); myCanvas.width = myCanvas.clientWidth; myCanvas.height = myCanvas.clientHeight; const ratio = Math.min( myCanvas.width / referenceWidth, myCanvas.height / referenceHeight ); const ctx = myCanvas.getContext("2d"); ctx.scale(ratio, ratio); drawFunction(ctx, ratio); window.requestAnimationFrame(() => { refresh(referenceWidth, referenceHeight, drawFunction); }); } //100, 100 is the "reference" size. Choose whatever you want. refresh(100, 100, (ctx, ratio) => { //Custom drawing code! Draw whatever you want here. const referenceLineWidth = 1; ctx.lineWidth = referenceLineWidth / ratio; ctx.beginPath(); ctx.strokeStyle = "blue"; ctx.arc(50, 50, 49, 0, 2 * Math.PI); ctx.stroke(); }); div { width: 90vw; height: 90vh; } canvas { width: 100%; height: 100%; object-fit: contain; } <div> <canvas id="myCanvas"></canvas> </div>

这个片段使用画布。clientWidth和canvas。clientHeight而不是window。innerWidth和window。innerHeight使代码段在复杂布局中正确运行。然而，如果你只是把它放在一个使用全窗口的div中，它也适用于全窗口。这样更灵活。

代码片段使用了新窗口。请求animationframe重复调整画布的大小每帧。如果不能使用此方法，请使用setTimeout代替。而且，这是低效的。为了提高效率，存储clientWidth和clienttheight，只有当clientWidth和clienttheight改变时才重新计算和绘制。

“参考”分辨率的想法让你可以使用一个分辨率编写所有的绘制命令……并且它会自动调整到客户端大小，而无需更改绘图代码。

这个片段是不言自明的，但如果你喜欢用英语解释:https://medium.com/@doomgoober/resizing-canvas-vector-graphics- with-aliasing -7a1f9e684e4d

2022的答案

在2022年，检查元素是否调整大小的推荐方法是使用ResizeObserver

const observer = new ResizeObserver(myResizeTheCanvasFn);
observer.observe(someCanvasElement);

它比窗户好。addEventListener('resize'， myResizeTheCanvasFn)或onresize = myResizeTheCanvasFn，因为它处理画布调整大小的每一种情况，即使它与窗口调整大小无关。

同样，使用window也没有意义。innerWidth window.innerHeight。你想要画布本身的大小，而不是窗口的大小。这样，无论你把画布放在哪里，你都会得到正确的大小，而不必重写你的尺寸代码。

至于用画布填满窗户

html, body {
  height: 100%;
}
canvas {
  width: 100%;
  height: 100%;
  display: block;   /* this is IMPORTANT! */
}

你需要display: block的原因是因为默认情况下画布是内联的，这意味着它在结尾包含额外的空间。没有显示:块你将得到一个滚动条。许多人通过在文档正文中添加overflow: hidden来修复滚动条问题，但这只是隐藏了画布的CSS设置不正确的事实。最好是修复bug(将canvas设置为display: block而不是使用overflow: hidden隐藏bug)

完整的示例

const canvas = document.querySelector('canvas'); const ctx = canvas.getContext('2d'); const observer = new ResizeObserver((entries) => { canvas.width = canvas.clientWidth; canvas.height = canvas.clientHeight; }); observer.observe(canvas) // not import but draw something just to showcase const hsla = (h, s, l, a) => `hsla(${h * 360}, ${s * 100}%, ${l * 100}%, ${a})`; function render(time) { const {width, height} = canvas; ctx.clearRect(0, 0, width, height); ctx.save(); ctx.translate(width / 2, height / 2); ctx.rotate(time * 0.0001); const range = Math.max(width, height) * 0.8; const size = 64 + Math.sin(time * 0.001) * 50; for (let i = 0; i < range; i += size) { ctx.fillStyle = hsla(i / range * 0.3 + time * 0.0001, 1, 0.5, 1); ctx.fillRect( i, -range, size, range * 2); ctx.fillRect(-i, -range, size, range * 2); } ctx.restore(); requestAnimationFrame(render) } requestAnimationFrame(render) html, body { height: 100%; margin: 0; } canvas { width: 100%; height: 100%; display: block; } <canvas></canvas>

注意:还有其他与调整画布大小相关的问题。特别是如果你想处理不同的devicePixelRatio设置。请参阅本文了解更多信息。

CSS

body { margin: 0; } 
canvas { display: block; } 

JavaScript

window.addEventListener("load", function()
{
    var canvas = document.createElement('canvas'); document.body.appendChild(canvas);
    var context = canvas.getContext('2d');

    function draw()
    {
        context.clearRect(0, 0, canvas.width, canvas.height);
        context.beginPath();
        context.moveTo(0, 0); context.lineTo(canvas.width, canvas.height); 
        context.moveTo(canvas.width, 0); context.lineTo(0, canvas.height); 
        context.stroke();
    }
    function resize()
    {
        canvas.width = window.innerWidth;
        canvas.height = window.innerHeight;
        draw();
    }
    window.addEventListener("resize", resize);
    resize();
});