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    <p>You can't directly pass an image from your extension to a web-page's canvas without making it tainted.<br> This is a work-around:</p> <p><strong>Description:</strong></p> <ol> <li>You access the image from your background page (or content script).</li> <li>You put it in a canvas and convert it to a dataURL.</li> <li>You inject some JS code into the web-page, passing the dataURL as a string.</li> <li>The injected code uses the string (dataURL) to create an image (in the context of the web-page) and draw it onto a canvas.</li> </ol> <p><strong>Sample code:</strong></p> <pre><code>/* In `background.js` */ function injectImg(tabID, remoteCanvasID, imgPath) { var canvas = document.createElement("canvas"); var img = new Image(); img.addEventListener("load", function() { canvas.getContext("2d").drawImage(img, 0, 0); var dataURL = canvas.toDataURL(); var code = [ "(function() {", " var canvas = document.getElementById(\"" + remoteCanvasID + "\");", " var img = new Image();", " img.addEventListener(\"load\", function() {", " canvas.getContext(\"2d\").drawImage(img, 0, 0);", " });", " img.src = \"" + dataURL + "\";", " ", "})();"].join("\n"); chrome.tabs.executeScript(tabID, { code: code }); }); img.src = chrome.extension.getURL(imgPath); } chrome.runtime.onMessage.addListener(function(msg, sender)) { if (msg.action &amp;&amp; (msg.action == "getImg") &amp;&amp; msg.imgPath &amp;&amp; msg.canvasID) { injectImg(sender.tab.id, msg.canvasID, msg.imgPath); } }); /* In `content.js` */ chrome.runtime.sendMessage({ action: "getImg", imgPath: "some/image.png", canvasID: "someCanvasID" }); </code></pre> <p>This is a more generic approach (that can be used by any content script with minimum configuration), but it might be simpler to move part of the logic to the content script. E.g.:</p> <ul> <li>Define a function within the content script, that when called with a dataURL creates and draws an image onto a canvas.</li> <li>Define a function in the background page, that takes an image-path and returns a dataURL (as seen above).</li> <li>Use <strong>chrome.runtime.getBackgroundPage()</strong> to get a reference to the background page's <code>window</code> object, call the function to convert an image-path to a dataURL and finally use that dataURL to create an image and draw it onto a canvas.</li> </ul>
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