The solution given by @spankajd is almost there but still not 100% accurate (as you’ll see the background image doesn’t completely fit to the canvas).
The proper solution to this problem is indeed to use the scaleX and scaleY property (which takes a number as scaling factor), as mentioned by @asturur on your submitted issue.
However, in that case you won’t need to set the width and height property of the image. Also, a better (and correct) way of setting those image properties is to pass them as options (argument) to the setBackgroundImage() method (this may resolve some performance issues), as such :
canvas.setBackgroundImage(img, canvas.renderAll.bind(canvas), {
scaleX: canvas.width / img.width,
scaleY: canvas.height / img.height
});
… instead of setting them for the image object separately.
that being said, here is a complete working example :
$(function() {
var canvas1 = new fabric.Canvas('canvas1');
//Default
var canvas = canvas1;
canvas.backgroundColor="#34AD39";
canvas.renderAll();
//Change background using Image
document.getElementById('bg_image').addEventListener('change', function(e) {
canvas.setBackgroundColor('', canvas.renderAll.bind(canvas));
canvas.setBackgroundImage(0, canvas.renderAll.bind(canvas));
var file = e.target.files[0];
var reader = new FileReader();
reader.onload = function(f) {
var data = f.target.result;
fabric.Image.fromURL(data, function(img) {
canvas.setBackgroundImage(img, canvas.renderAll.bind(canvas), {
scaleX: canvas.width / img.width,
scaleY: canvas.height / img.height
});
});
};
reader.readAsDataURL(file);
});
});<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/2.0.0-beta.7/fabric.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div style="margin-top:20px;">
<label class="control-label">Add Background Image</label>
<input type="file" id="bg_image" />
</div>
<canvas id="canvas1" width="600" height="400" style="border:1px solid #000"></canvas>