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diff --git a/files/zh-cn/web/api/canvasrenderingcontext2d/save/index.html b/files/zh-cn/web/api/canvasrenderingcontext2d/save/index.html new file mode 100644 index 0000000000..167c40fd19 --- /dev/null +++ b/files/zh-cn/web/api/canvasrenderingcontext2d/save/index.html @@ -0,0 +1,170 @@ +--- +title: CanvasRenderingContext2D.save() +slug: Web/API/CanvasRenderingContext2D/save +translation_of: Web/API/CanvasRenderingContext2D/save +--- +<div>{{APIRef}}</div> + +<p><code><strong>CanvasRenderingContext2D</strong></code><strong><code>.save()</code></strong> 是 Canvas 2D API 通过将当前状态放入栈中,保存 canvas 全部状态的方法。</p> + +<h2 id="语法">语法</h2> + +<pre class="syntaxbox">void <var><em>ctx</em>.save();</var></pre> + +<h2 id="绘制状态">绘制状态</h2> + +<p>保存到栈中的绘制状态有下面部分组成:</p> + +<ul> + <li>当前的变换矩阵。</li> + <li>当前的剪切区域。</li> + <li>当前的虚线列表.</li> + <li>以下属性当前的值: {{domxref("CanvasRenderingContext2D.strokeStyle", "strokeStyle")}}, {{domxref("CanvasRenderingContext2D.fillStyle", "fillStyle")}}, {{domxref("CanvasRenderingContext2D.globalAlpha", "globalAlpha")}}, {{domxref("CanvasRenderingContext2D.lineWidth", "lineWidth")}}, {{domxref("CanvasRenderingContext2D.lineCap", "lineCap")}}, {{domxref("CanvasRenderingContext2D.lineJoin", "lineJoin")}}, {{domxref("CanvasRenderingContext2D.miterLimit", "miterLimit")}}, {{domxref("CanvasRenderingContext2D.lineDashOffset", "lineDashOffset")}}, {{domxref("CanvasRenderingContext2D.shadowOffsetX", "shadowOffsetX")}}, {{domxref("CanvasRenderingContext2D.shadowOffsetY", "shadowOffsetY")}}, {{domxref("CanvasRenderingContext2D.shadowBlur", "shadowBlur")}}, {{domxref("CanvasRenderingContext2D.shadowColor", "shadowColor")}}, {{domxref("CanvasRenderingContext2D.globalCompositeOperation", "globalCompositeOperation")}}, {{domxref("CanvasRenderingContext2D.font", "font")}}, {{domxref("CanvasRenderingContext2D.textAlign", "textAlign")}}, {{domxref("CanvasRenderingContext2D.textBaseline", "textBaseline")}}, {{domxref("CanvasRenderingContext2D.direction", "direction")}}, {{domxref("CanvasRenderingContext2D.imageSmoothingEnabled", "imageSmoothingEnabled")}}.</li> +</ul> + +<h2 id="示例">示例</h2> + +<h3 id="使用_save_方法">使用 <code>save</code> 方法</h3> + +<p>这是一段简单的代码片段,使用 <code>save</code> 方法保存默认的状态,这样,稍后你就可以使用默认的设置绘制一个矩形。</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.save(); // 保存默认的状态 + +ctx.fillStyle = "green"; +ctx.fillRect(10, 10, 100, 100); + +ctx.restore(); // 还原到上次保存的默认状态 +ctx.fillRect(150, 75, 100, 100); +</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"><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.save(); +ctx.fillStyle = "green"; +ctx.fillRect(10, 10, 100, 100); +ctx.restore(); +ctx.fillRect(150, 75, 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> + +<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-save", "CanvasRenderingContext2D.save")}}</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> + +<h2 id="参见">参见</h2> + +<ul> + <li>接口定义, {{domxref("CanvasRenderingContext2D")}}.</li> + <li>{{domxref("CanvasRenderingContext2D.restore()")}}</li> +</ul> |