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diff --git a/files/zh-cn/web/api/canvasrenderingcontext2d/settransform/index.html b/files/zh-cn/web/api/canvasrenderingcontext2d/settransform/index.html new file mode 100644 index 0000000000..23302386e7 --- /dev/null +++ b/files/zh-cn/web/api/canvasrenderingcontext2d/settransform/index.html @@ -0,0 +1,129 @@ +--- +title: CanvasRenderingContext2D.setTransform() +slug: Web/API/CanvasRenderingContext2D/setTransform +translation_of: Web/API/CanvasRenderingContext2D/setTransform +--- +<div>{{APIRef}}</div> + +<p><code><strong>CanvasRenderingContext2D</strong></code><strong><code>.setTransform()</code></strong> 是 Canvas 2D API 使用单位矩阵重新设置（覆盖）当前的变换并调用变换的方法，此变换由方法的变量进行描述。</p> + +<p>参见 {{domxref("CanvasRenderingContext2D.transform()", "transform()")}} 方法，这个方法不会覆盖当前的变换矩阵，会多次叠加变换。</p> + +<h2 id="语法">语法</h2> + +<pre class="syntaxbox notranslate">void <var><em>ctx</em>.setTransform(a, b, c, d, e, f);</var> +</pre> + +<p>变换矩阵的描述： <math><semantics><mrow><mo>[</mo><mtable columnalign="center center center" rowspacing="0.5ex"><mtr><mtd><mi>a</mi></mtd><mtd><mi>c</mi></mtd><mtd><mi>e</mi></mtd></mtr><mtr><mtd><mi>b</mi></mtd><mtd><mi>d</mi></mtd><mtd><mi>f</mi></mtd></mtr><mtr><mtd><mn>0</mn></mtd><mtd><mn>0</mn></mtd><mtd><mn>1</mn></mtd></mtr></mtable><mo>]</mo></mrow><annotation encoding="TeX">\left[ \begin{array}{ccc} a & c & e \\ b & d & f \\ 0 & 0 & 1 \end{array} \right]</annotation></semantics></math></p> + +<h3 id="参数">参数</h3> + +<dl> + <dt><code>a (m11)</code></dt> + <dd>水平缩放。</dd> + <dt><em><code>b (m12)</code></em></dt> + <dd>垂直倾斜。</dd> + <dt><code>c (m21)</code></dt> + <dd>水平倾斜。</dd> + <dt><code>d (m22)</code></dt> + <dd>垂直缩放。</dd> + <dt><code>e (dx)</code></dt> + <dd>水平移动。</dd> + <dt><code>f (dy)</code></dt> + <dd>垂直移动。</dd> +</dl> + +<p>较新的类型由单个参数矩阵组成，该参数表示要设置的2D转换矩阵（从技术上讲，是DOMMatrixInit对象；任何对象只要包含上述作为属性的组件，就可以执行操作）。</p> + +<h2 id="示例">示例</h2> + +<h3 id="使用_setTransform_方法">使用 <code>setTransform</code> 方法</h3> + +<p>这是一段使用 <code>setTransform</code> 方法的简单的代码片段。</p> + +<h4 id="HTML">HTML</h4> + +<pre class="brush: html notranslate"><canvas id="canvas"></canvas> +</pre> + +<h4 id="JavaScript">JavaScript</h4> + +<pre class="brush: js; highlight:[4] notranslate">var canvas = document.getElementById("canvas"); +var ctx = canvas.getContext("2d"); + +ctx.setTransform(1,1,0,1,0,0); +ctx.fillRect(0,0,100,100); +</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 notranslate"><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.setTransform(1,1,0,1,0,0); +ctx.fillRect(0,0,100,100);</textarea> +</pre> + +<pre class="brush: js notranslate">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-settransform", "CanvasRenderingContext2D.setTransform")}}</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>{{Compat("api.CanvasRenderingContext2D.setTransform")}}</p> + +<h2 id="参见">参见</h2> + +<ul> + <li>接口定义， {{domxref("CanvasRenderingContext2D")}}</li> + <li>{{domxref("CanvasRenderingContext2D.transform()")}}</li> +</ul> |