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---
title: CanvasRenderingContext2D.direction
slug: Web/API/CanvasRenderingContext2D/direction
tags:
- Canvas
- CanvasRenderingContext2D
translation_of: Web/API/CanvasRenderingContext2D/direction
---
<div>{{APIRef}} {{SeeCompatTable}}</div>
<p><code><strong>CanvasRenderingContext2D</strong></code><strong><code>.direction</code></strong> 是Canvas 2D API 用来在绘制文本时，描述当前文本方向的属性。</p>
<h2 id="语法">语法</h2>
<pre class="syntaxbox"><var><em>ctx</em>.direction = "ltr" || "rtl" || "inherit";</var>
</pre>
<h3 id="选项">选项</h3>
<p>有效值:</p>
<dl>
<dt>ltr</dt>
<dd>文本方向从左向右。</dd>
<dt>rtl</dt>
<dd>文本方向从右向左。</dd>
<dt>inherit</dt>
<dd>根据情况继承 {{HTMLElement("canvas")}} 元素或者 {{domxref("Document")}} 。</dd>
</dl>
<p>默认值是<code>inherit。</code></p>
<h2 id="示例">示例</h2>
<h3 id="Using_the_direction_property" name="Using_the_direction_property">使用<code>direction</code> 属性</h3>
<p>这是一段简单的代码片段，对文本设置不同的direction数值。</p>
<h4 id="HTML">HTML</h4>
<pre class="brush: html"><canvas id="canvas"></canvas></pre>
<h4 id="JavaScript">JavaScript</h4>
<pre class="brush: js">var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
ctx.font = '48px serif';
ctx.fillText('Hi!', 150, 50);
ctx.direction = 'rtl';
ctx.fillText('Hi!', 150, 130);</pre>
<div class="hidden">
<h6 id="Playable_code" name="Playable_code">Playable code</h6>
<pre class="brush: html"><canvas id="canvas" width="550" height="500"></canvas>
</pre>
<pre class="brush: js">var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
ctx.font = '48px serif';
ctx.fillText('Hi!', 150, 50);
ctx.direction = 'rtl';
ctx.fillText('Hi!', 150, 130);</pre>
</div>
<h4 id="结果">结果</h4>
<p>{{ EmbedLiveSample('Playable_code', 700, 180) }}</p>
<h2 id="规范描述">规范描述</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', "scripting.html#dom-context-2d-direction", "CanvasRenderingContext2D.direction")}}</td>
<td>{{Spec2('HTML WHATWG')}}</td>
<td></td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<p>{{Compat("api.CanvasRenderingContext2D.direction")}}</p>
<h2 id="参见">参见</h2>
<ul>
<li>接口定义， {{domxref("CanvasRenderingContext2D")}}.</li>
</ul>
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