---
title: CanvasRenderingContext2D.putImageData()
slug: Web/API/CanvasRenderingContext2D/putImageData
translation_of: Web/API/CanvasRenderingContext2D/putImageData
---
<div>{{APIRef}}</div>

<p><code><strong>CanvasRenderingContext2D</strong></code><strong><code>.putImageData()</code></strong> 是 Canvas 2D API 将数据从已有的 {{domxref("ImageData")}} 对象绘制到位图的方法。 如果提供了一个绘制过的矩形，则只绘制该矩形的像素。此方法不受画布转换矩阵的影响。</p>

<h2 id="语法">语法</h2>

<pre class="syntaxbox">void <var><em>ctx</em>.putImageData(imagedata, dx, dy);</var>
void <var><em>ctx</em>.putImageData(imagedata, dx, dy, dirtyX, dirtyY, dirtyWidth, dirtyHeight);</var>
</pre>

<h3 id="参数">参数</h3>

<p><strong>imageData</strong></p>

<p>     {{domxref("ImageData")}} ，包含像素值的数组对象。</p>

<dl>
 <dt><code>dx</code></dt>
 <dd>源图像数据在目标画布中的位置偏移量（x 轴方向的偏移量）。</dd>
 <dt><code>dy</code></dt>
 <dd>源图像数据在目标画布中的位置偏移量（y 轴方向的偏移量）。</dd>
 <dt><code>dirtyX</code> {{optional_inline}}</dt>
 <dd>在源图像数据中，矩形区域左上角的位置。默认是整个图像数据的左上角（x 坐标）。</dd>
 <dt><code>dirtyY</code> {{optional_inline}}</dt>
 <dd>在源图像数据中，矩形区域左上角的位置。默认是整个图像数据的左上角（y 坐标）。</dd>
 <dt><code>dirtyWidth</code> {{optional_inline}}</dt>
 <dd>在源图像数据中，矩形区域的宽度。默认是图像数据的宽度。</dd>
 <dt><code>dirtyHeight</code> {{optional_inline}}</dt>
 <dd>在源图像数据中，矩形区域的高度。默认是图像数据的高度。</dd>
</dl>

<h3 id="抛出错误">抛出错误</h3>

<dl>
 <dt><code>NotSupportedError</code></dt>
 <dd>如果任何一个变量被设置成无穷大，则会抛出此错误。</dd>
 <dt><code>InvalidStateError</code></dt>
 <dd>如果过图像数据对象的数据被分离，会抛出此错误。</dd>
</dl>

<h2 id="示例">示例</h2>

<h3 id="理解putImageData">理解<code>putImageData</code></h3>

<p>通过{{domxref("CanvasRenderingContext2D.fillRect()")}}方法实现，更好地理解putImageData的执行算法. 获取更多信息，参见 <a href="/en-US/docs/Web/API/Canvas_API/Tutorial/Pixel_manipulation_with_canvas">使用Canvas控制像素</a> 和 {{domxref("ImageData")}} 对象。</p>

<h4 id="HTML">HTML</h4>

<pre class="brush: html">&lt;canvas id="canvas"&gt;&lt;/canvas&gt;
</pre>

<h4 id="JavaScript">JavaScript</h4>

<pre class="brush: js">var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");

function putImageData(ctx, imageData, dx, dy,
    dirtyX, dirtyY, dirtyWidth, dirtyHeight) {
  var data = imageData.data;
  var height = imageData.height;
  var width = imageData.width;
  dirtyX = dirtyX || 0;
  dirtyY = dirtyY || 0;
  dirtyWidth = dirtyWidth !== undefined? dirtyWidth: width;
  dirtyHeight = dirtyHeight !== undefined? dirtyHeight: height;
  var limitBottom = dirtyY + dirtyHeight;
  var limitRight = dirtyX + dirtyWidth;
  for (var y = dirtyY; y &lt; limitBottom; y++) {
    for (var x = dirtyX; x &lt; limitRight; x++) {
      var pos = y * width + x;
      ctx.fillStyle = 'rgba(' + data[pos*4+0]
                        + ',' + data[pos*4+1]
                        + ',' + data[pos*4+2]
                        + ',' + (data[pos*4+3]/255) + ')';
      ctx.fillRect(x + dx, y + dy, 1, 1);
    }
  }
}

// Draw content onto the canvas
ctx.fillRect(0,0,100,100);
// Create an ImageData object from it
var imagedata = ctx.getImageData(0,0,100,100);
// use the putImageData function that illustrates how putImageData works
putImageData(ctx, imagedata, 150, 0, 50, 50, 25, 25);
</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">&lt;canvas id="canvas" width="400" height="200" class="playable-canvas"&gt;&lt;/canvas&gt;
&lt;div class="playable-buttons"&gt;
  &lt;input id="edit" type="button" value="Edit" /&gt;
  &lt;input id="reset" type="button" value="Reset" /&gt;
&lt;/div&gt;
&lt;textarea id="code" class="playable-code"&gt;
ctx.fillRect(0,0,100,100);
var imagedata = ctx.getImageData(0,0,100,100);
putImageData(ctx, imagedata, 150, 0, 50, 50, 25, 25);&lt;/textarea&gt;
</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);

function putImageData(ctx, imageData, dx, dy,
    dirtyX, dirtyY, dirtyWidth, dirtyHeight) {
  var data = imageData.data;
  var height = imageData.height;
  var width = imageData.width;
  dirtyX = dirtyX || 0;
  dirtyY = dirtyY || 0;
  dirtyWidth = dirtyWidth !== undefined? dirtyWidth: width;
  dirtyHeight = dirtyHeight !== undefined? dirtyHeight: height;
  var limitBottom = dirtyY + dirtyHeight;
  var limitRight = dirtyX + dirtyWidth;
  for (var y = dirtyY; y &lt; limitBottom; y++) {
    for (var x = dirtyX; x &lt; limitRight; x++) {
      var pos = y * width + x;
      ctx.fillStyle = 'rgba(' + data[pos*4+0]
                        + ',' + data[pos*4+1]
                        + ',' + data[pos*4+2]
                        + ',' + (data[pos*4+3]/255) + ')';
      ctx.fillRect(x + dx, y + dy, 1, 1);
    }
  }
}
</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-putimagedata", "CanvasRenderingContext2D.putImageData")}}</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.putImageData")}}

<h2 id="参见">参见</h2>

<ul>
 <li>接口定义， {{domxref("CanvasRenderingContext2D")}}.</li>
 <li>{{domxref("ImageData")}}</li>
 <li><a href="/en-US/docs/Web/API/Canvas_API/Tutorial/Pixel_manipulation_with_canvas">Pixel manipulation with canvas</a></li>
</ul>