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diff --git a/files/zh-cn/web/api/canvasrenderingcontext2d/putimagedata/index.html b/files/zh-cn/web/api/canvasrenderingcontext2d/putimagedata/index.html new file mode 100644 index 0000000000..2719f7901c --- /dev/null +++ b/files/zh-cn/web/api/canvasrenderingcontext2d/putimagedata/index.html @@ -0,0 +1,242 @@ +--- +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"><canvas id="canvas"></canvas> +</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 < limitBottom; y++) { + for (var x = dirtyX; x < 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 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.fillRect(0,0,100,100); +var imagedata = ctx.getImageData(0,0,100,100); +putImageData(ctx, imagedata, 150, 0, 50, 50, 25, 25);</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); + +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 < limitBottom; y++) { + for (var x = dirtyX; x < 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> + +<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> + +<h3 id="兼容性注解">兼容性注解</h3> + +<ul> + <li>从 Gecko 10.0 {{ geckoRelease("10.0") }}开始，给任何参数设置非限定性的值并调用 <code>putImageData()</code> 将会被忽略，而不是抛出异常。</li> + <li>为了遵循说明，从 Gecko 16.0 {{geckoRelease("16.0")}}开始，使用无效的变量数量调用该方法（只有3个或7个数的变量是有效的）， 将会抛出一个错误 ({{bug(762657)}})。</li> +</ul> + +<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> |