initial commit

1 files changed, 133 insertions, 0 deletions

diff --git a/files/zh-cn/web/api/canvasrenderingcontext2d/drawfocusifneeded/index.html b/files/zh-cn/web/api/canvasrenderingcontext2d/drawfocusifneeded/index.html
new file mode 100644
index 0000000000..1dc87fb0b2
--- /dev/null
+++ b/files/zh-cn/web/api/canvasrenderingcontext2d/drawfocusifneeded/index.html
@@ -0,0 +1,133 @@
+---
+title: CanvasRenderingContext2D.drawFocusIfNeeded()
+slug: Web/API/CanvasRenderingContext2D/drawFocusIfNeeded
+translation_of: Web/API/CanvasRenderingContext2D/drawFocusIfNeeded
+---
+<div>{{APIRef}}</div>
+
+<p><code><strong>CanvasRenderingContext2D</strong></code><strong><code>.drawFocusIfNeeded()</code></strong> 是 Canvas 2D API 用来给当前路径或特定路径绘制焦点的方法，如果给定的元素获取了焦点。</p>
+
+<h2 id="语法">语法</h2>
+
+<pre class="syntaxbox notranslate">void <var><em>ctx</em>.drawFocusIfNeeded(element);<var>
+void <var><em>ctx</em>.drawFocusIfNeeded(path, element);</var></var></var>
+</pre>
+
+<h3 id="参数">参数</h3>
+
+<dl>
+ <dt>element</dt>
+ <dd>是否需要设置焦点的元素。</dd>
+ <dt><code>path</code></dt>
+ <dd>{{domxref("Path2D")}} 路径。</dd>
+</dl>
+
+<h2 id="示例">示例</h2>
+
+<h3 id="使用_drawFocusIfNeeded_方法">使用 <code>drawFocusIfNeeded</code> 方法</h3>
+
+<p>这是一段使用 <code>drawFocusIfNeeded</code> 方法的简单的代码片段。</p>
+
+<h4 id="HTML">HTML</h4>
+
+<pre class="brush: html notranslate">&lt;canvas id="canvas"&gt;
+  &lt;input id="button" type="range" min="1" max="12"&gt;
+&lt;/canvas&gt;
+</pre>
+
+<h4 id="JavaScript">JavaScript</h4>
+
+<pre class="brush: js; highlight:[9] notranslate">var canvas = document.getElementById("canvas");
+var ctx = canvas.getContext("2d");
+var button = document.getElementById("button");
+
+button.focus();
+
+ctx.beginPath();
+ctx.rect(10, 10, 30, 30);
+ctx.drawFocusIfNeeded(button);
+</pre>
+
+<p>修改下面的代码并在线查看 canvas的变化：</p>
+
+<div style="display: none;">
+<h6 id="Playable_code">Playable code</h6>
+
+<pre class="brush: html notranslate">&lt;canvas id="canvas" width="400" height="200" class="playable-canvas"&gt;
+&lt;input id="button" type="range" min="1" max="12"&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"&gt;
+ctx.beginPath();
+ctx.rect(10, 10, 30, 30);
+ctx.drawFocusIfNeeded(button);&lt;/textarea&gt;
+</pre>
+
+<pre class="brush: js notranslate">var canvas = document.getElementById("canvas");
+var ctx = canvas.getContext("2d");
+var textarea = document.getElementById("code");
+var button = document.getElementById("button");
+var reset = document.getElementById("reset");
+var edit = document.getElementById("edit");
+var code = textarea.value;
+button.focus();
+
+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-drawfocusifneeded", "CanvasRenderingContext2D.drawFocusIfNeeded")}}</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>
+
+
+
+<p>{{Compat("api.CanvasRenderingContext2D.drawFocusIfNeeded")}}</p>
+
+<h3 id="兼容性注解">兼容性注解</h3>
+
+<ul>
+ <li>[1] 在 Gecko 28 {{geckoRelease(28)}}中， 此方法通过 "<code>drawSystemFocusRing</code>" 实现， 但是在 Gecko 29 {{geckoRelease(29)}}中已经改名。</li>
+ <li>[1] 在 Gecko 32 {{geckoRelease(32)}} 之前，此方法默认是无效的，受控于 flag "<code>canvas.focusring.enabled</code>"标识。</li>
+</ul>
+
+<h2 id="参见">参见</h2>
+
+<ul>
+ <li>接口定义， {{domxref("CanvasRenderingContext2D")}}.</li>
+</ul>