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---
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 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.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>
{{Compat("api.CanvasRenderingContext2D.save")}}
<h2 id="参见">参见</h2>
<ul>
<li>接口定义， {{domxref("CanvasRenderingContext2D")}}.</li>
<li>{{domxref("CanvasRenderingContext2D.restore()")}}</li>
</ul>
|
