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---
title: CanvasRenderingContext2D.isPointInPath()
slug: Web/API/CanvasRenderingContext2D/isPointInPath
translation_of: Web/API/CanvasRenderingContext2D/isPointInPath
---
<div>{{APIRef}}</div>
<p><code style="font-style: normal;"><strong>CanvasRenderingContext2D</strong></code><strong><code>.isPointInPath()</code></strong>是 Canvas 2D API 用于判断在当前路径中是否包含检测点的方法<font face="Courier New, Andale Mono, monospace"><strong>。</strong></font></p>
<h2 id="语法">语法</h2>
<pre class="syntaxbox">boolean <var><em>ctx</em>.isPointInPath(x, y);
boolean <var><em>ctx</em>.isPointInPath(x, y, fillRule);
boolean <var><em>ctx</em>.isPointInPath(path, x, y);
boolean <var><em>ctx</em>.isPointInPath(path, x, y, fillRule);</var></var></var></var>
</pre>
<h3 id="参数">参数</h3>
<dl>
<dt>x</dt>
<dd>检测点的X坐标</dd>
<dt>y</dt>
<dd>检测点的Y坐标</dd>
<dt><code>fillRule</code></dt>
<dd>用来决定点在路径内还是在路径外的算法。<br>
允许的值：
<ul>
<li><code><strong>"nonzero</strong></code>": <a href="http://en.wikipedia.org/wiki/Nonzero-rule">非零环绕规则 </a>，默认的规则。</li>
<li><code><strong>"evenodd"</strong></code>: <a href="http://en.wikipedia.org/wiki/Even%E2%80%93odd_rule">奇偶环绕原则 </a>。</li>
</ul>
</dd>
<dt><code>path</code></dt>
<dd>{{domxref("Path2D")}}应用的路径。</dd>
</dl>
<h3 id="返回值">返回值</h3>
<dl>
<dt>{{jsxref("Boolean")}}</dt>
<dd>一个Boolean值，当检测点包含在当前或指定的路径内，返回 true；否则返回 false。</dd>
</dl>
<h2 id="示例">示例</h2>
<h3 id="使用_isPointInPath_方法">使用 <code>isPointInPath</code> 方法</h3>
<p>这是一段简单的代码片段，使用 <code>isPointInPath</code> 方法检查某点是否在当前的路径内。</p>
<h4 id="HTML">HTML</h4>
<pre class="brush: html"><canvas id="canvas"></canvas>
</pre>
<h4 id="JavaScript">JavaScript</h4>
<pre class="brush: js; highlight:[6]">var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
ctx.rect(10, 10, 100, 100);
ctx.stroke();
console.log(ctx.isPointInPath(10, 10)); // true
</pre>
<p>修改下面的代码， 在线查看 canvas的变化并在你的 <a href="/en-US/docs/Tools/Browser_Console">控制台</a> 中观察日志信息：</p>
<div class="hidden">
<h6 id="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.rect(10, 10, 100, 100);
ctx.stroke();
console.log(ctx.isPointInPath(10, 10)); // true</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>
<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-ispointinpath", "CanvasRenderingContext2D.isPointInPath")}}</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>{{ CompatibilityTable() }}</p>
<div id="compat-desktop">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Chrome</th>
<th>Firefox (Gecko)</th>
<th>Internet Explorer</th>
<th>Opera</th>
<th>Safari</th>
</tr>
<tr>
<td>Basic support</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
</tr>
<tr>
<td>Path parameter</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatGeckoDesktop(31) }}</td>
<td>{{ CompatNo }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatNo }}</td>
</tr>
</tbody>
</table>
</div>
<div id="compat-mobile">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Android</th>
<th>Chrome for Android</th>
<th>Firefox Mobile (Gecko)</th>
<th>IE Mobile</th>
<th>Opera Mobile</th>
<th>Safari Mobile</th>
</tr>
<tr>
<td>Basic support</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
</tr>
<tr>
<td>Path parameter</td>
<td>{{ CompatUnknown() }}</td>
<td>{{ CompatUnknown() }}</td>
<td>{{ CompatGeckoMobile(31) }}</td>
<td>{{ CompatUnknown() }}</td>
<td>{{ CompatUnknown() }}</td>
<td>{{ CompatUnknown() }}</td>
</tr>
</tbody>
</table>
</div>
<h3 id="Compatibility_注解">Compatibility 注解</h3>
<ul>
<li>在 Gecko 7.0 (Firefox 7.0 / Thunderbird 7.0 / SeaMonkey 2.4)之前，这个方法是错误的，在和路径进行比较前，该方法不会根据当前的变形矩阵增加指定点的坐标。现在，该方法可以正确执行，甚至上下文进行旋转、缩放或其他方式的变形。</li>
</ul>
<h2 id="参见">参见</h2>
<ul>
<li>接口定义， {{domxref("CanvasRenderingContext2D")}}.</li>
</ul>
|
