function draw(canvas){
	"use strict";
	
	canvas.setAttribute("width", 220);
	canvas.setAttribute("height", 30);
	
	var fp_text = "BrowserLeaks,com <canvas> 10";
	
	var ctx = canvas.getContext("2d");
	ctx.textBaseline = "top";
	ctx.font = "14px 'Arial'";
	ctx.textBaseline = "alphabetic";
	ctx.fillStyle = "#f60";
	ctx.fillRect(125, 1, 62, 20);
	ctx.fillStyle = "#069";
	ctx.fillText(fp_text, 2, 15);
	ctx.fillStyle = "rgba(102, 204, 0, 07)";
	ctx.fillText(fp_text, 4, 17);
	
	return ctx;
}
function test(window){
	"use strict";
	
	// create window canvas
	var canvas = document.createElement("canvas");
	// draw image in window canvas
	draw(canvas);
	return window.HTMLCanvasElement.prototype.toDataURL.call(canvas);
}
function hash(string){
	"use strict";
	
	var buffer = new TextEncoder("utf-8").encode(string);
	return crypto.subtle.digest("SHA-256", buffer).then(function(hash){
		var chunks = [];
		(new Uint32Array(hash)).forEach(function(num){
			chunks.push(num.toString(16));
		});
		return chunks.map(function(chunk){
			return "0".repeat(8 - chunk.length) + chunk;
		}).join("");
	});
	
}

var addLine = function(){
	"use strict";
	
	var output = document.getElementById("results");
	return function(text){
		var line = document.createElement("div");
		line.textContent = text;
		output.appendChild(line);
	};
}();

addLine("window name at start: " + window.name);
window.name = "CanvasBlocker CSP test";
addLine("window name after set: " + window.name);
hash(test(window)).then(function(hash){
	"use strict";
	
	addLine("canvas hash: " + hash);
	return;
}).catch(function(error){
	"use strict";
	
	addLine("error while creating canvas hash: " + error);
});