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| author | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
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| committer | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
| commit | 33058f2b292b3a581333bdfb21b8f671898c5060 (patch) | |
| tree | 51c3e392513ec574331b2d3f85c394445ea803c6 /files/zh-cn/web/api/canvasrenderingcontext2d/globalcompositeoperation | |
| parent | 8b66d724f7caf0157093fb09cfec8fbd0c6ad50a (diff) | |
| download | translated-content-33058f2b292b3a581333bdfb21b8f671898c5060.tar.gz translated-content-33058f2b292b3a581333bdfb21b8f671898c5060.tar.bz2 translated-content-33058f2b292b3a581333bdfb21b8f671898c5060.zip | |
initial commit
Diffstat (limited to 'files/zh-cn/web/api/canvasrenderingcontext2d/globalcompositeoperation')
| -rw-r--r-- | files/zh-cn/web/api/canvasrenderingcontext2d/globalcompositeoperation/index.html | 143 |
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diff --git a/files/zh-cn/web/api/canvasrenderingcontext2d/globalcompositeoperation/index.html b/files/zh-cn/web/api/canvasrenderingcontext2d/globalcompositeoperation/index.html new file mode 100644 index 0000000000..47544ad6e2 --- /dev/null +++ b/files/zh-cn/web/api/canvasrenderingcontext2d/globalcompositeoperation/index.html @@ -0,0 +1,143 @@ +--- +title: CanvasRenderingContext2D.globalCompositeOperation +slug: Web/API/CanvasRenderingContext2D/globalCompositeOperation +tags: + - Canvas + - CanvasRenderingContext2D +translation_of: Web/API/CanvasRenderingContext2D/globalCompositeOperation +--- +<div>{{APIRef}}</div> + +<p>Canvas 2D API的 <code><strong>CanvasRenderingContext2D</strong></code><strong><code>.globalCompositeOperation</code></strong> 属性设置要在绘制新形状时应用的合成操作的类型,其中type是用于标识要使用的合成或混合模式操作的字符串。</p> + +<p>在 <a href="/en-US/docs/Web/API/Canvas_API/Tutorial">Canvas Tutorial</a> 中查看 <a href="/en-US/docs/Web/API/Canvas_API/Tutorial/Compositing">Compositing</a> 章节。</p> + +<h2 id="语法">语法</h2> + +<pre class="syntaxbox"><var><em>ctx</em>.globalCompositeOperation = type;</var></pre> + +<h3 id="类型">类型</h3> + +<p>{{EmbedLiveSample("合成示例", 750, 6750, "" ,"Web/API/Canvas_API/Tutorial/Compositing/Example")}}</p> + +<h2 id="示例">示例</h2> + +<h3 id="Using_the_globalAlpha_property" name="Using_the_globalAlpha_property">使用 <code>globalCompositeOperation</code> 属性</h3> + +<p>这是一段使用 <code>globalCompositeOperation</code> 属性的简单的代码片段,绘制了2个矩形在重叠时相互排斥的情况。</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[4]">var canvas = document.getElementById("canvas"); +var ctx = canvas.getContext("2d"); + +ctx.globalCompositeOperation = "xor"; + +ctx.fillStyle = "blue"; +ctx.fillRect(10, 10, 100, 100); + +ctx.fillStyle = "red"; +ctx.fillRect(50, 50, 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" style="height:120px;"> +ctx.globalCompositeOperation = "xor"; + +ctx.fillStyle = "blue"; +ctx.fillRect(10, 10, 100, 100); + +ctx.fillStyle = "red"; +ctx.fillRect(50, 50, 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, 380) }}</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-globalcompositeoperation", "CanvasRenderingContext2D.globalCompositeOperation")}}</td> + <td>{{Spec2('HTML WHATWG')}}</td> + <td></td> + </tr> + <tr> + <td>{{SpecName('Compositing')}}</td> + <td>{{Spec2('Compositing')}}</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。</p> +</div> + +<p>{{Compat("api.CanvasRenderingContext2D.globalCompositeOperation")}}</p> + +<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.setCompositeOperation()</code>。</li> +</ul> + +<h3 id="Gecko-specific_注解">Gecko-specific 注解</h3> + +<ul> + <li>早起的规范草案指定了 "darker"值。 然而, Firefox 在第4个版本({{bug(571532)}})移除了对 "darker"的支持。参见 <a href="http://dropshado.ws/post/77229081704/firefox-doesnt-support-canvas-composite-darker">这篇文章</a> 建议如何使用不同的值实现和"darker"类似的效果。</li> +</ul> + +<h2 id="参见">参见</h2> + +<ul> + <li>接口定义,{{domxref("CanvasRenderingContext2D")}}</li> + <li>{{domxref("CanvasRenderingContext2D.globalAlpha")}}</li> +</ul> |
