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

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<!DOCTYPE html>
<html>
<head>
	<meta charset="UTF-8">
	<title>Forest and Trees Demo</title>
	<style type='text/css'>
		canvas {
			border: 1px solid black;
		}
	</style>
</head>
<body>
	<canvas id='canvas' width='1024' height='768'></canvas>
	<script type='text/javascript'>
		var ctx;
		var x, y, x1, y1, x2, y2, x3, y3, n;

		function drawTree( ctx, x, y ) {
			ctx.fillStyle = "rgb(134,83,0)";
			ctx.fillRect(x+17,y+50,16,50);
			ctx.strokeRect(x+16.5,y+49.5,16,50);
			ctx.beginPath();
			ctx.moveTo(x+25,y);
			ctx.lineTo(x,y+75);
			ctx.lineTo(x+50,y+75);
			ctx.lineTo(x+25,y);
			ctx.fillStyle = "rgb(0,255,0)";
			ctx.fill();
			ctx.stroke();
		}

		function drawForest( ctx, x, y, w, h ) {
			ctx.strokeRect(x,y,w,h);
			for ( var n=0; n<100; n++ ) {
				var a = Math.floor( Math.random()*(w-50) );
				var b = Math.floor( Math.random()*(h-100) );
				drawTree(ctx, x+a, y+b);
			}
		}

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

			// draws a few single trees for testing
			drawTree(ctx, 30,550);
			drawTree(ctx,100,580);
			drawTree(ctx,640,300);
			drawTree(ctx,730,370);

			// draws the first forest
			ctx.strokeRect(10,10,500,500);
			drawForest(ctx,10,10,500,500);

			// draws the second forest
			ctx.strokeRect(550,20,400,250);
			drawForest(ctx,550,20,400,250);

			// draws the third forest
			ctx.strokeRect(200,530,710,160);
			drawForest(ctx,200,530,710,160);
		}

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

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