Can I get image from canvas element and use it in img src tag?

Question

Is there possibility to convert the image present in a canvas element into an image representing by img src?

I need that to crop an image after some transformation and save it. There are a view functions that I found on the internet like: FileReader() or ToBlop(), toDataURL(), getImageData(), but I have no idea how to implement and use them properly in JavaScript.

This is my html:

<img src="http://picture.jpg" id="picture" style="display:none"/>
<tr>
    <td>
        <canvas id="transform_image"></canvas>
    </td>
</tr>
<tr>
    <td>
        <div id="image_for_crop">image from canvas</div>
    </td>
</tr>

In JavaScript it should look something like this:

$(document).ready(function() {
    img = document.getElementById('picture');
    canvas = document.getElementById('transform_image');

    if(!canvas || !canvas.getContext){
        canvas.parentNode.removeChild(canvas);
    } else {
        img.style.position = 'absolute';
    }
    transformImg(90);
    ShowImg(imgFile);
}

function transformImg(degree) {
    if (document.getElementById('transform_image')) {
        var Context = canvas.getContext('2d');
        var cx = 0, cy = 0;
        var picture = $('#picture');
        var displayedImg = {
            width: picture.width(),
            height: picture.height()
        };   
        var cw = displayedImg.width, ch = displayedImg.height
        Context.rotate(degree * Math.PI / 180);
        Context.drawImage(img, cx, cy, cw, ch);
    }
}

function showImg(imgFile) {
    if (!imgFile.type.match(/image.*/))
    return;

    var img = document.createElement("img"); // creat img object
    img.id = "pic"; //I need set some id
    img.src = imgFile; // my picture representing by src
    document.getElementById('image_for_crop').appendChild(img); //my image for crop
}

How can I change the canvas element into an img src image in this script? (There may be some bugs in this script.)

Answer 1

canvas.toDataURL() will provide you a data url which can be used as source:

var image = new Image();
image.id = "pic";
image.src = canvas.toDataURL();
document.getElementById('image_for_crop').appendChild(image);

See also:

• MDN: canvas.toDataURL() documentation