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javascriptcanvasgoogle-chrome-extensionscreenshotwebpage-screenshot

Mouse disappers when screenshot of a webpage is clicked

I have developed a chrome extension which takes screenshots of webpages. I have noticed that when I take screenshots of some pages, the mouse in the screenshot disappears. Therefore I am not able to know which place did the click occur later.

How could this be resolved ?

Solution

  • You would need to draw a mouse cursor yourself. Here is an example of making screenshot on mouse click and drawing red circle where the cursor was:

    content_script.js:

    window.addEventListener("click", function(event) {
    chrome.extension.sendRequest({x: event.x, y: event.y});
});

    background.html:

    <html>
<head>
<script>
chrome.extension.onRequest.addListener(function(request, sender, sendResponse) {
    chrome.tabs.captureVisibleTab(null, {format:"png"}, function(dataUrl){

        var img = new Image();
        img.onload = function(){
            var canvas = document.getElementById("canvas");
            canvas.width = img.width;
            canvas.height = img.height;

            var ctx = canvas.getContext("2d");

            ctx.drawImage(img, 0, 0);
            ctx.arc(request.x, request.y, 5, 0, Math.PI*2, true);
            ctx.fillStyle = "rgb(255,0,0)";
            ctx.fill();

            chrome.tabs.create({url: canvas.toDataURL("image/png")});
        };
        img.src = dataUrl;

    });
    sendResponse({});
});
</script>
</head>
<body>
    <canvas id="canvas"></canvas>
</body>
</html>