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---
title: CanvasPattern.setTransform()
slug: Web/API/CanvasPattern/setTransform
translation_of: Web/API/CanvasPattern/setTransform
---
<div>{{APIRef("Canvas API")}} {{SeeCompatTable}}</div>
<p><code><strong>CanvasPattern</strong></code><strong><code>.setTransform()</code></strong> 方法使用 {{domxref("SVGMatrix")}} 对象作为图案的变换矩阵，并在此图案上调用它。</p>
<h2 id="语法">语法</h2>
<pre class="syntaxbox">void <var><em>pattern</em>.setTransform(matrix);</var>
</pre>
<h3 id="参数">参数</h3>
<dl>
<dt><code>matrix</code></dt>
<dd>{{domxref("SVGMatrix")}} ，被用作图案的变换矩阵。</dd>
</dl>
<h2 id="示例">示例</h2>
<h3 id="使用_setTransform_方法">使用 <code>setTransform</code> 方法</h3>
<p>这是一段简单的代码片段，使用 <code>setTransform</code> 方法创建一个来自 {{domxref("SVGMatrix")}} 具有指定图案变化的{{domxref("CanvasPattern")}} 。如例子所示，如果你把图案赋值给当前的 {{domxref("CanvasRenderingContext2D.fillStyle", "fillStyle")}} ，当你使用 {{domxref("CanvasRenderingContext2D.fillRect", "fillRect()")}} 方法时，图案会被应用到 canvas 上绘制出效果。</p>
<h4 id="HTML">HTML</h4>
<pre class="brush: html"><canvas id="canvas"></canvas>
<svg id="svg1"></svg>
</pre>
<h4 id="JavaScript">JavaScript</h4>
<pre class="brush: js; highlight:[12]">var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var svg1 = document.getElementById("svg1");
var matrix = svg1.createSVGMatrix();
var img = new Image();
img.src = 'https://mdn.mozillademos.org/files/222/Canvas_createpattern.png';
img.onload = function() {
var pattern = ctx.createPattern(img, 'repeat');
pattern.setTransform(matrix.rotate(-45).scale(1.5));
ctx.fillStyle = pattern;
ctx.fillRect(0,0,400,400);
};
</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>
<svg id="svg1" style="display:none"></svg>
<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">
var img = new Image();
img.src = 'https://mdn.mozillademos.org/files/222/Canvas_createpattern.png';
img.onload = function() {
var pattern = ctx.createPattern(img, 'repeat');
pattern.setTransform(matrix.rotate(-45).scale(1.5));
ctx.fillStyle = pattern;
ctx.fillRect(0,0,400,400);
};</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;
var svg1 = document.getElementById("svg1");
var matrix = svg1.createSVGMatrix();
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-canvaspattern-settransform", "CanvasPattern.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>
{{Compat("api.CanvasPattern.setTransform")}}
<h2 id="参见">参见</h2>
<ul>
<li>接口定义，{{domxref("CanvasPattern")}}</li>
<li>{{domxref("SVGMatrix")}}</li>
</ul>
|
