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---
title: CanvasRenderingContext2D.strokeStyle
slug: Web/API/CanvasRenderingContext2D/strokeStyle
tags:
- Canvas
- CanvasRenderingContext2D
translation_of: Web/API/CanvasRenderingContext2D/strokeStyle
---
<div>{{APIRef}}</div>
<p><code><strong>CanvasRenderingContext2D</strong></code><strong><code>.strokeStyle</code></strong> 是 Canvas 2D API 描述画笔（绘制图形）颜色或者样式的属性。默认值是 <code>#000</code> (black)。</p>
<p>参见 <a href="/en-US/docs/Web/API/Canvas_API/Tutorial">Canvas Tutorial</a> 中的 <a href="/en-US/docs/Web/API/Canvas_API/Tutorial/Applying_styles_and_colors">Applying styles and color</a> 章节。</p>
<h2 id="语法">语法</h2>
<pre class="syntaxbox"><var><em>ctx</em>.strokeStyle = color;
</var><var><em>ctx</em>.strokeStyle = gradient;
</var><var><em>ctx</em>.strokeStyle = pattern;</var>
</pre>
<h3 id="选项">选项</h3>
<dl>
<dt><code>color</code></dt>
<dd>{{domxref("DOMString")}} 字符串，可以转换成 CSS {{cssxref("<color>")}} 值。</dd>
<dt><code>gradient</code></dt>
<dd>{{domxref("CanvasGradient")}} 对象（线性渐变或放射性渐变）。</dd>
<dt><code>pattern</code></dt>
<dd>{{domxref("CanvasPattern")}} 对象（可重复的图片）。</dd>
</dl>
<h2 id="示例">示例</h2>
<h3 id="Using_the_strokeStyle_property" name="Using_the_strokeStyle_property">使用 <code>strokeStyle</code> 属性设置不同的颜色</h3>
<p>这是一段简单的代码片段，使用 <code>strokeStyle</code> 属性设置不同的颜色。</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.strokeStyle = "blue";
ctx.strokeRect(10, 10, 100, 100);
</pre>
<p>修改下面的代码并在线查看 canvas 的变化：</p>
<div class="hidden">
<h6 id="Playable_code" name="Playable_code">Playable code</h6>
<pre class="brush: html"><canvas id="canvas" width="400" height="200" class="playable-canvas"></canvas>
<div class="playable-buttons">
<input id="edit" type="button" value="Edit" />
<input id="reset" type="button" value="Reset" />
</div>
<textarea id="code" class="playable-code">
ctx.strokeStyle = "blue";
ctx.strokeRect(10, 10, 100, 100);</textarea>
</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, 360) }}</p>
<h3 id="A_strokeStyle_example" name="A_strokeStyle_example"><code>strokeStyle</code> 例子</h3>
<p>这个例子使用 <code>strokeStyle 属性改变图形轮廓线的颜色。</code>我们使用 {{domxref("CanvasRenderingContext2D.arc", "arc()")}} 绘制圆形来代替正方形。</p>
<pre class="brush: js">var ctx = document.getElementById('canvas').getContext('2d');
for (var i=0;i<6;i++){
for (var j=0;j<6;j++){
ctx.strokeStyle = 'rgb(0,' + Math.floor(255-42.5*i) + ',' +
Math.floor(255-42.5*j) + ')';
ctx.beginPath();
ctx.arc(12.5+j*25,12.5+i*25,10,0,Math.PI*2,true);
ctx.stroke();
}
}
</pre>
<div class="hidden">
<pre class="brush: html"><canvas id="canvas" width="150" height="150"></canvas></pre>
</div>
<p>结果如下显示：</p>
<p>{{EmbedLiveSample("A_strokeStyle_example", "180", "180", "https://mdn.mozillademos.org/files/253/Canvas_strokestyle.png")}}</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-strokestyle", "CanvasRenderingContext2D.strokeStyle")}}</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>
<div class="hidden">
<p>此页面上的兼容性表是根据结构化数据生成的。 如果您想提供数据，请查看 <a href="https://github.com/mdn/browser-compat-data">https://github.com/mdn/browser-compat-data</a> 并向我们发送请求请求。</p>
</div>
<p>{{Compat("api.CanvasRenderingContext2D.strokeStyle")}}</p>
<div id="compat-mobile"></div>
<h3 id="WebKitBlink-specific_注解">WebKit/Blink-specific 注解</h3>
<ul>
<li>在基于 WebKit- 和 Blink- 的浏览器中，除了此属性外，还实现了一个不标准的并且不赞成使用的方法 <code>ctx.setStrokeColor()</code> 。
<pre class="brush: js">setStrokeColor(color, optional alpha);
setStrokeColor(grayLevel, optional alpha);
setStrokeColor(r, g, b, a);
setStrokeColor(c, m, y, k, a);
</pre>
</li>
</ul>
<h2 id="参见">参见</h2>
<ul>
<li>接口定义， {{domxref("CanvasRenderingContext2D")}}</li>
<li>{{domxref("CanvasGradient")}}</li>
<li>{{domxref("CanvasPattern")}}</li>
</ul>
|
