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diff --git a/files/zh-cn/web/api/canvasrenderingcontext2d/linejoin/index.html b/files/zh-cn/web/api/canvasrenderingcontext2d/linejoin/index.html new file mode 100644 index 0000000000..df108cd01a --- /dev/null +++ b/files/zh-cn/web/api/canvasrenderingcontext2d/linejoin/index.html @@ -0,0 +1,213 @@ +--- +title: CanvasRenderingContext2D.lineJoin +slug: Web/API/CanvasRenderingContext2D/lineJoin +translation_of: Web/API/CanvasRenderingContext2D/lineJoin +--- +<div>{{APIRef}}</div> + +<p><code><strong>CanvasRenderingContext2D</strong></code><strong><code>.lineJoin</code></strong> 是 Canvas 2D API 用来设置2个长度不为0的相连部分（线段，圆弧，曲线）如何连接在一起的属性（长度为0的变形部分，其指定的末端和控制点在同一位置，会被忽略）。</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>.lineJoin = "bevel"; +<var><em>ctx</em>.lineJoin = "round"; +<var><em>ctx</em>.lineJoin = "miter";</var></var></var></pre> + +<h3 id="选项">选项</h3> + +<p>此属性有3个值： <code>round</code>, <code>bevel</code> and <code>miter</code>。默认值是 <code>miter。注意：如果2个相连部分在同一方向，那么lineJoin不会产生任何效果</code>，因为在那种情况下不会出现连接区域。</p> + +<p><img alt="" src="https://mdn.mozillademos.org/files/237/Canvas_linejoin.png" style="float: right; height: 190px; width: 190px;"></p> + +<dl> + <dt><code>round</code></dt> + <dd>通过填充一个额外的，圆心在相连部分末端的扇形，绘制拐角的形状。 圆角的半径是线段的宽度。</dd> + <dt><code>bevel</code></dt> + <dd>在相连部分的末端填充一个额外的以三角形为底的区域， 每个部分都有各自独立的矩形拐角。</dd> + <dt><code>miter</code></dt> + <dd>通过延伸相连部分的外边缘，使其相交于一点，形成一个额外的菱形区域。这个设置可以通过 {{domxref("CanvasRenderingContext2D.miterLimit", "miterLimit")}} 属性看到效果。</dd> +</dl> + +<h2 id="示例">示例</h2> + +<h3 id="Using_the_lineCap_property" name="Using_the_lineCap_property">使用 <code>lineJoin</code> 属性</h3> + +<p>这是一段使用 <code>lineJoin</code> 属性的简单的代码片段。</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[5]">var canvas = document.getElementById("canvas"); +var ctx = canvas.getContext("2d"); + +ctx.lineWidth = 10; +ctx.lineJoin = "round"; +ctx.beginPath(); +ctx.moveTo(0,0); +ctx.lineTo(200, 100); +ctx.lineTo(300,0); +ctx.stroke(); +</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" style="height:120px;"> +ctx.lineWidth = 10; +ctx.lineJoin = "round"; +ctx.beginPath(); +ctx.moveTo(0,0); +ctx.lineTo(200, 100); +ctx.lineTo(300,0); +ctx.stroke();</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, 380) }}</p> + +<h3 id="A_lineJoin_example" name="A_lineJoin_example"><code>lineJoin</code> 例子</h3> + +<p>下面的例子绘制了3条不同的路径，演示 <code>lineJoin</code> 属性3种不同的设置。</p> + +<pre class="brush: js">var ctx = document.getElementById('canvas').getContext('2d'); +var lineJoin = ['round','bevel','miter']; +ctx.lineWidth = 10; + +for (var i = 0; i < lineJoin.length; i++) { + ctx.lineJoin = lineJoin[i]; + ctx.beginPath(); + ctx.moveTo(-5,5+i*40); + ctx.lineTo(35,45+i*40); + ctx.lineTo(75,5+i*40); + ctx.lineTo(115,45+i*40); + ctx.lineTo(155,5+i*40); + ctx.stroke(); +} +</pre> + +<div class="hidden"> +<pre class="brush: html"><canvas id="canvas" width="150" height="150"></canvas></pre> +</div> + +<p>{{EmbedLiveSample("A_lineJoin_example", "180", "180", "https://mdn.mozillademos.org/files/237/Canvas_linejoin.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-linejoin", "CanvasRenderingContext2D.lineJoin")}}</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> + </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> + </tbody> +</table> +</div> + +<h3 id="WebKitBlink-specific_注解">WebKit/Blink-specific 注解</h3> + +<ul> + <li>基于WebKit- 和 Blink- 的浏览器中， 实现了一个不标准的并且不赞成使用的方法 <code>ctx.setLineJoin()</code> 。</li> +</ul> + +<h2 id="参见">参见</h2> + +<ul> + <li>接口定义， {{domxref("CanvasRenderingContext2D")}}</li> + <li>{{domxref("CanvasRenderingContext2D.lineCap")}}</li> + <li>{{domxref("CanvasRenderingContext2D.lineWidth")}}</li> +</ul> |