---
title: CanvasRenderingContext2D.imageSmoothingQuality
slug: Web/API/CanvasRenderingContext2D/imageSmoothingQuality
tags:
  - API
  - Canvas
  - CanvasRenderingContext2D
  - imageSmoothingQuality
  - 图像平滑度
translation_of: Web/API/CanvasRenderingContext2D/imageSmoothingQuality
---
<div>{{APIRef}} {{SeeCompatTable}}</div>

<p><strong>CanvasRenderingContext2D.imageSmoothingQuality</strong> 是 Canvas 2D API， 用于设置图像平滑度的属性。</p>

<h2 id="语法">语法</h2>

<pre class="syntaxbox"><var><em>ctx</em>.</var>imageSmoothingQuality<var> = value
value</var> = ctx.imageSmoothingQuality</pre>

<h3 id="选项">选项</h3>

<dl>
 <dt><code>value</code></dt>
 <dd>"low","medium","high"</dd>
</dl>

<h2 id="示例">示例</h2>

<h3 id="使用_imageSmoothingQuality_属性">使用 imageSmoothingQuality 属性</h3>

<p>这是一段简单的代码片段，对缩放的图片使用 <code>imageSmoothingQuality </code>属性。</p>

<h4 id="HTML">HTML</h4>

<pre class="brush: html">&lt;canvas id="canvas"&gt;&lt;/canvas&gt;
</pre>

<h4 id="JavaScript">JavaScript</h4>

<pre class="brush: js; highlight[7-10]">var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");

var img = new Image();
img.src = 'https://mdn.mozillademos.org/files/222/Canvas_createpattern.png';
img.onload = function() {
 ctx.mozImageSmoothingEnabled = false;
 ctx.imageSmoothingQuality = "Medium";
 ctx.webkitImageSmoothingEnabled = false;
 ctx.msImageSmoothingEnabled = false;
 ctx.imageSmoothingEnabled = false;
 ctx.drawImage(img, 0, 0, 400, 200);
};</pre>

<p>编辑下面代码，在线查看 Canvas 的变化：</p>

<div class="hidden">
<h6 id="Playable_code">Playable code</h6>

<pre class="brush: html">&lt;canvas id="canvas" width="400" height="200" class="playable-canvas"&gt;&lt;/canvas&gt;
&lt;div class="playable-buttons"&gt;
  &lt;input id="edit" type="button" value="Edit" /&gt;
  &lt;input id="reset" type="button" value="Reset" /&gt;
&lt;/div&gt;
&lt;textarea id="code" class="playable-code" style="height:140px;"&gt;
var img = new Image();
img.src = 'https://mdn.mozillademos.org/files/222/Canvas_createpattern.png';
img.onload = function() {
 ctx.mozImageSmoothingEnabled = false;
 ctx.webkitImageSmoothingEnabled = false;
 ctx.imageSmoothingQuality = "Medium";
 ctx.msImageSmoothingEnabled = false;
 ctx.imageSmoothingEnabled = false;
 ctx.drawImage(img, 0, 0, 400, 200);
};&lt;/textarea&gt;
</pre>

<pre class="brush: js">var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var textarea = document.getElementById("code");
var reset = document.getElementById("reset");
var edit = document.getElementById("edit");
var code = textarea.value;

function drawCanvas() {
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  eval(textarea.value);
}

reset.addEventListener("click", function() {
  textarea.value = code;
  drawCanvas();
});

edit.addEventListener("click", function() {
  textarea.focus();
})

textarea.addEventListener("input", drawCanvas);
window.addEventListener("load", drawCanvas);
</pre>
</div>

<p>{{ EmbedLiveSample('Playable_code', 700, 400) }}</p>

<h2 id="规范">规范</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
  <tr>
   <td>{{SpecName('HTML WHATWG', "#imagesmoothingquality", "imageSmoothingQuality")}}</td>
   <td>{{Spec2('HTML WHATWG')}}</td>
   <td>Initial definition.</td>
  </tr>
 </tbody>
</table>

<h2 id="浏览器兼容性">浏览器兼容性</h2>

{{Compat("api.CanvasRenderingContext2D.imageSmoothingQuality")}}

<h2 id="参见">参见</h2>

<ul>
 <li>接口定义, {{domxref("CanvasRenderingContext2D")}}</li>
 <li>{{cssxref("image-rendering")}}</li>
</ul>