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$(document).ready(function(){
var canvas = new fabric.Canvas('logo');
canvas.backgroundColor="green";
var mask = new fabric.Rect({
left: 0,
top: 0,
width: 600,
height: 200,
fill: 'blue'
});
canvas.add(mask);
var text = new fabric.Text("TEST TEXT", {
fontSize: 120,
fontFamily: 'Arial',
stroke: "black",
fill: 'none',
fillRule: 'destination-out'
});
canvas.add(text);
});