braska · January 15, 2016 19:21
diff --git a/index.html b/index.html
 <html>
 <head>
    <meta charset="utf-8"/>
    <title>HTML5 Canvas Drawing Board</title>
    <script type="text/JavaScript" src="https://code.jquery.com/jquery-2.2.0.min.js"></script>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        body, html {
            height: 100%;
        }

        #myCanvas {
            cursor: crosshair;
            position: fixed;
        }

        #cover {
            position: fixed;
            top: 100px;
            left: 50px;
        }
    </style>

 </head>
 <body>

 <img src="http://lorempixel.com/150/150/cats" id="cover">

 <canvas id="myCanvas">
    Sorry, your browser does not support HTML5 canvas technology.
 </canvas>


 <script>
    window.onload = function () {
        var myCanvas = document.getElementById("myCanvas");
        var ctx = myCanvas.getContext("2d");

        // Fill Window Width and Height
        myCanvas.width = window.innerWidth;
        myCanvas.height = window.innerHeight;

        var imageObj = new Image();
        imageObj.src = 'http://www.html5canvastutorials.com/demos/assets/darth-vader.jpg';
        var width = myCanvas.width;
        var height = myCanvas.height;

        imageObj.onload = function () {
            ctx.drawImage(imageObj, 0, 0, width, height);
            ctx.globalCompositeOperation = 'destination-out';
            ctx.strokeStyle = 'rgba(255,0,0,255)';
        };

        // Mouse Event Handlers
        if (myCanvas) {
            var isDown = false;
            var canvasX, canvasY;
            ctx.lineWidth = 50;

            $(myCanvas)
                    .on('mousedown touchstart', function (e) {
                        isDown = true;
                        ctx.beginPath();
                        canvasX = e.originalEvent.touches == undefined ? e.pageX - myCanvas.offsetLeft : e.originalEvent.touches[0].pageX;
                        canvasY = e.originalEvent.touches == undefined ? e.pageY - myCanvas.offsetLeft : e.originalEvent.touches[0].pageY;
                        ctx.moveTo(canvasX, canvasY);
                    })
                    .on('mousemove touchmove', function (e) {
                        console.log(e);
                        if (isDown !== false) {
                            canvasX = e.originalEvent.touches == undefined ? e.pageX - myCanvas.offsetLeft : e.originalEvent.touches[0].pageX;
                            canvasY = e.originalEvent.touches == undefined ? e.pageY - myCanvas.offsetLeft : e.originalEvent.touches[0].pageY;
                            ctx.lineTo(canvasX, canvasY);
                            ctx.stroke();
                        }
                    })
                    .on('mouseup touchend', function (e) {
                        isDown = false;
                        ctx.closePath();
                    });
        }

        // Disable Page Move
        document.body.addEventListener('touchmove', function (evt) {
            evt.preventDefault();
        }, false);
    };
 </script>
 </body>
 </html>
	<html>
	<head>
	<meta charset="utf-8"/>
	<title>HTML5 Canvas Drawing Board</title>
	<script type="text/JavaScript" src="https://code.jquery.com/jquery-2.2.0.min.js"></script>
	<style>
	* {
	margin: 0;
	padding: 0;
	}

	body, html {
	height: 100%;
	}

	#myCanvas {
	cursor: crosshair;
	position: fixed;
	}

	#cover {
	position: fixed;
	top: 100px;
	left: 50px;
	}
	</style>

	</head>
	<body>

	<img src="http://lorempixel.com/150/150/cats" id="cover">

	<canvas id="myCanvas">
	Sorry, your browser does not support HTML5 canvas technology.
	</canvas>


	<script>
	window.onload = function () {
	var myCanvas = document.getElementById("myCanvas");
	var ctx = myCanvas.getContext("2d");

	// Fill Window Width and Height
	myCanvas.width = window.innerWidth;
	myCanvas.height = window.innerHeight;

	var imageObj = new Image();
	imageObj.src = 'http://www.html5canvastutorials.com/demos/assets/darth-vader.jpg';
	var width = myCanvas.width;
	var height = myCanvas.height;

	imageObj.onload = function () {
	ctx.drawImage(imageObj, 0, 0, width, height);
	ctx.globalCompositeOperation = 'destination-out';
	ctx.strokeStyle = 'rgba(255,0,0,255)';
	};

	// Mouse Event Handlers
	if (myCanvas) {
	var isDown = false;
	var canvasX, canvasY;
	ctx.lineWidth = 50;

	$(myCanvas)
	.on('mousedown touchstart', function (e) {
	isDown = true;
	ctx.beginPath();
	canvasX = e.originalEvent.touches == undefined ? e.pageX - myCanvas.offsetLeft : e.originalEvent.touches[0].pageX;
	canvasY = e.originalEvent.touches == undefined ? e.pageY - myCanvas.offsetLeft : e.originalEvent.touches[0].pageY;
	ctx.moveTo(canvasX, canvasY);
	})
	.on('mousemove touchmove', function (e) {
	console.log(e);
	if (isDown !== false) {
	canvasX = e.originalEvent.touches == undefined ? e.pageX - myCanvas.offsetLeft : e.originalEvent.touches[0].pageX;
	canvasY = e.originalEvent.touches == undefined ? e.pageY - myCanvas.offsetLeft : e.originalEvent.touches[0].pageY;
	ctx.lineTo(canvasX, canvasY);
	ctx.stroke();
	}
	})
	.on('mouseup touchend', function (e) {
	isDown = false;
	ctx.closePath();
	});
	}

	// Disable Page Move
	document.body.addEventListener('touchmove', function (evt) {
	evt.preventDefault();
	}, false);
	};
	</script>
	</body>
	</html>