java-visualizations/SmilingFaceDemo.html at master · grahammitchell/java-visualizations · GitHub

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<!DOCTYPE html>
<html>
<head>
	<meta charset="UTF-8">
	<title>Smiling Face Demo</title>
	<style type='text/css'>
		canvas {
			border: 1px solid black;
		}
	</style>
</head>
<body>
	<canvas id='canvas' width='400' height='300'></canvas>
	<script type='text/javascript'>
		var ctx;

		function drawLine( ctx, x1, y1, x2, y2 ) {
			ctx.beginPath();
			ctx.moveTo(x1-0.5, y1-0.5);
			ctx.lineTo(x2-0.5, y2-0.5);
			ctx.closePath();
			ctx.stroke();
		}

		function drawGrid( ctx ) {
			var X, Y;
			ctx.save();
			ctx.fillStyle = "black";
			ctx.font = "10px sans-serif";
			// labels
			for ( X=50; X<ctx.canvas.width; X+=50 )
				ctx.fillText( ""+X, X-7, 48 );
			for ( Y=100; Y<ctx.canvas.height; Y+=50 )
				ctx.fillText( ""+Y, 15, Y+3 );
			// lines
			ctx.strokeStyle = "#cccccc";
			for ( X=0; X<ctx.canvas.width; X+=50 )
				drawLine(ctx, X, 0, X, ctx.canvas.height-1); // horizontal
			for ( Y=0; Y<ctx.canvas.height; Y+=50 )
				drawLine(ctx, 0, Y, ctx.canvas.width-1, Y); // vertical
			ctx.restore();
		}

		function circle( ctx, cx, cy, rad ) {
			ctx.beginPath();
			ctx.arc(cx, cy, rad, 0, 2*Math.PI, false);
			ctx.fill();
		}

		function draw(ctx) {
			ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);

			// draw head
			ctx.fillStyle = "yellow";
			circle(ctx, 200, 150, 100);

			// eyes
			ctx.fillStyle = "blue";
			circle(ctx, 160, 125, 20);
			circle(ctx, 240, 125, 20);

			// mouth
			ctx.strokeStyle = "red";
			ctx.beginPath();
			ctx.arc(200,170,50,Math.PI/5,4*Math.PI/5);
			ctx.stroke();

			// drawGrid(ctx);
		}

		function main() {
			ctx = document.getElementById('canvas').getContext("2d");
			draw(ctx);
		}

		main();
	</script>
</body>
</html>