text: /**
  Copyright (c) 2010 Dennis Hotson
  
   Permission is hereby granted, free of charge, to any person
   obtaining a copy of this software and associated documentation
   files (the "Software"), to deal in the Software without
   restriction, including without limitation the rights to use,
   copy, modify, merge, publish, distribute, sublicense, and/or sell
   copies of the Software, and to permit persons to whom the
   Software is furnished to do so, subject to the following
   conditions:
  
   The above copyright notice and this permission notice shall be
   included in all copies or substantial portions of the Software.
  
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   OTHER DEALINGS IN THE SOFTWARE.
  */
  
  (function() {
  
  jQuery.fn.springy = function(params) {
  	var graph = this.graph = params.graph || new Springy.Graph();
  	var nodeFont = "16px Verdana, sans-serif";
  	var edgeFont = "8px Verdana, sans-serif";
  	var stiffness = params.stiffness || 400.0;
  	var repulsion = params.repulsion || 400.0;
  	var damping = params.damping || 0.5;
  	var nodeSelected = params.nodeSelected || null;
  	var nodeImages = {};
  	var edgeLabelsUpright = true;
  
  	var canvas = this[0];
  	var ctx = canvas.getContext("2d");
  
  	var layout = this.layout = new Springy.Layout.ForceDirected(graph, stiffness, repulsion, damping);
  
  	// calculate bounding box of graph layout.. with ease-in
  	var currentBB = layout.getBoundingBox();
  	var targetBB = {bottomleft: new Springy.Vector(-2, -2), topright: new Springy.Vector(2, 2)};
  
  	// auto adjusting bounding box
  	Springy.requestAnimationFrame(function adjust() {
  		targetBB = layout.getBoundingBox();
  		// current gets 20% closer to target every iteration
  		currentBB = {
  			bottomleft: currentBB.bottomleft.add( targetBB.bottomleft.subtract(currentBB.bottomleft)
  				.divide(10)),
  			topright: currentBB.topright.add( targetBB.topright.subtract(currentBB.topright)
  				.divide(10))
  		};
  
  		Springy.requestAnimationFrame(adjust);
  	});
  
  	// convert to/from screen coordinates
  	var toScreen = function(p) {
  		var size = currentBB.topright.subtract(currentBB.bottomleft);
  		var sx = p.subtract(currentBB.bottomleft).divide(size.x).x * canvas.width;
  		var sy = p.subtract(currentBB.bottomleft).divide(size.y).y * canvas.height;
  		return new Springy.Vector(sx, sy);
  	};
  
  	var fromScreen = function(s) {
  		var size = currentBB.topright.subtract(currentBB.bottomleft);
  		var px = (s.x / canvas.width) * size.x + currentBB.bottomleft.x;
  		var py = (s.y / canvas.height) * size.y + currentBB.bottomleft.y;
  		return new Springy.Vector(px, py);
  	};
  
  	// half-assed drag and drop
  	var selected = null;
  	var nearest = null;
  	var dragged = null;
  
  	jQuery(canvas).mousedown(function(e) {
  		var pos = jQuery(this).offset();
  		var p = fromScreen({x: e.pageX - pos.left, y: e.pageY - pos.top});
  		selected = nearest = dragged = layout.nearest(p);
  
  		if (selected.node !== null) {
  			dragged.point.m = 10000.0;
  
  			if (nodeSelected) {
  				nodeSelected(selected.node);
  			}
  		}
  
  		renderer.start();
  	});
  
  	// Basic double click handler
  	jQuery(canvas).dblclick(function(e) {
  		var pos = jQuery(this).offset();
  		var p = fromScreen({x: e.pageX - pos.left, y: e.pageY - pos.top});
  		selected = layout.nearest(p);
  		node = selected.node;
  		if (node && node.data && node.data.ondoubleclick) {
  			node.data.ondoubleclick();
  		}
  	});
  
  	jQuery(canvas).mousemove(function(e) {
  		var pos = jQuery(this).offset();
  		var p = fromScreen({x: e.pageX - pos.left, y: e.pageY - pos.top});
  		nearest = layout.nearest(p);
  
  		if (dragged !== null && dragged.node !== null) {
  			dragged.point.p.x = p.x;
  			dragged.point.p.y = p.y;
  		}
  
  		renderer.start();
  	});
  
  	jQuery(window).bind('mouseup',function(e) {
  		dragged = null;
  	});
  
  	var getTextWidth = function(node) {
  		var text = (node.data.label !== undefined) ? node.data.label : node.id;
  		if (node._width && node._width[text])
  			return node._width[text];
  
  		ctx.save();
  		ctx.font = (node.data.font !== undefined) ? node.data.font : nodeFont;
  		var width = ctx.measureText(text).width;
  		ctx.restore();
  
  		node._width || (node._width = {});
  		node._width[text] = width;
  
  		return width;
  	};
  
  	var getTextHeight = function(node) {
  		return 16;
  		// In a more modular world, this would actually read the font size, but I think leaving it a constant is sufficient for now.
  		// If you change the font size, I'd adjust this too.
  	};
  
  	var getImageWidth = function(node) {
  		var width = (node.data.image.width !== undefined) ? node.data.image.width : nodeImages[node.data.image.src].object.width;
  		return width;
  	}
  
  	var getImageHeight = function(node) {
  		var height = (node.data.image.height !== undefined) ? node.data.image.height : nodeImages[node.data.image.src].object.height;
  		return height;
  	}
  
  	Springy.Node.prototype.getHeight = function() {
  		var height;
  		if (this.data.image == undefined) {
  			height = getTextHeight(this);
  		} else {
  			if (this.data.image.src in nodeImages && nodeImages[this.data.image.src].loaded) {
  				height = getImageHeight(this);
  			} else {height = 10;}
  		}
  		return height;
  	}
  
  	Springy.Node.prototype.getWidth = function() {
  		var width;
  		if (this.data.image == undefined) {
  			width = getTextWidth(this);
  		} else {
  			if (this.data.image.src in nodeImages && nodeImages[this.data.image.src].loaded) {
  				width = getImageWidth(this);
  			} else {width = 10;}
  		}
  		return width;
  	}
  
  	var renderer = this.renderer = new Springy.Renderer(layout,
  		function clear() {
  			ctx.clearRect(0,0,canvas.width,canvas.height);
  		},
  		function drawEdge(edge, p1, p2) {
  			var x1 = toScreen(p1).x;
  			var y1 = toScreen(p1).y;
  			var x2 = toScreen(p2).x;
  			var y2 = toScreen(p2).y;
  
  			var direction = new Springy.Vector(x2-x1, y2-y1);
  			var normal = direction.normal().normalise();
  
  			var from = graph.getEdges(edge.source, edge.target);
  			var to = graph.getEdges(edge.target, edge.source);
  
  			var total = from.length + to.length;
  
  			// Figure out edge's position in relation to other edges between the same nodes
  			var n = 0;
  			for (var i=0; i<from.length; i++) {
  				if (from[i].id === edge.id) {
  					n = i;
  				}
  			}
  
  			//change default to  10.0 to allow text fit between edges
  			var spacing = 12.0;
  
  			// Figure out how far off center the line should be drawn
  			var offset = normal.multiply(-((total - 1) * spacing)/2.0 + (n * spacing));
  
  			var paddingX = 6;
  			var paddingY = 6;
  
  			var s1 = toScreen(p1).add(offset);
  			var s2 = toScreen(p2).add(offset);
  
  			var boxWidth = edge.target.getWidth() + paddingX;
  			var boxHeight = edge.target.getHeight() + paddingY;
  
  			var intersection = intersect_line_box(s1, s2, {x: x2-boxWidth/2.0, y: y2-boxHeight/2.0}, boxWidth, boxHeight);
  
  			if (!intersection) {
  				intersection = s2;
  			}
  
  			var stroke = (edge.data.color !== undefined) ? edge.data.color : '#000000';
  
  			var arrowWidth;
  			var arrowLength;
  
  			var weight = (edge.data.weight !== undefined) ? edge.data.weight : 1.0;
  
  			ctx.lineWidth = Math.max(weight *  2, 0.1);
  			arrowWidth = 1 + ctx.lineWidth;
  			arrowLength = 8;
  
  			var directional = (edge.data.directional !== undefined) ? edge.data.directional : true;
  
  			// line
  			var lineEnd;
  			if (directional) {
  				lineEnd = intersection.subtract(direction.normalise().multiply(arrowLength * 0.5));
  			} else {
  				lineEnd = s2;
  			}
  
  			ctx.strokeStyle = stroke;
  			ctx.beginPath();
  			ctx.moveTo(s1.x, s1.y);
  			ctx.lineTo(lineEnd.x, lineEnd.y);
  			ctx.stroke();
  
  			// arrow
  			if (directional) {
  				ctx.save();
  				ctx.fillStyle = stroke;
  				ctx.translate(intersection.x, intersection.y);
  				ctx.rotate(Math.atan2(y2 - y1, x2 - x1));
  				ctx.beginPath();
  				ctx.moveTo(-arrowLength, arrowWidth);
  				ctx.lineTo(0, 0);
  				ctx.lineTo(-arrowLength, -arrowWidth);
  				ctx.lineTo(-arrowLength * 0.8, -0);
  				ctx.closePath();
  				ctx.fill();
  				ctx.restore();
  			}
  
  			// label
  			if (edge.data.label !== undefined) {
  				text = edge.data.label
  				ctx.save();
  				ctx.textAlign = "center";
  				ctx.textBaseline = "top";
  				ctx.font = (edge.data.font !== undefined) ? edge.data.font : edgeFont;
  				ctx.fillStyle = stroke;
  				var angle = Math.atan2(s2.y - s1.y, s2.x - s1.x);
  				var displacement = -8;
  				if (edgeLabelsUpright && (angle > Math.PI/2 || angle < -Math.PI/2)) {
  					displacement = 8;
  					angle += Math.PI;
  				}
  				var textPos = s1.add(s2).divide(2).add(normal.multiply(displacement));
  				ctx.translate(textPos.x, textPos.y);
  				ctx.rotate(angle);
  				ctx.fillText(text, 0,-2);
  				ctx.restore();
  			}
  
  		},
  		function drawNode(node, p) {
  			var s = toScreen(p);
  
  			ctx.save();
  
  			// Pulled out the padding aspect sso that the size functions could be used in multiple places
  			// These should probably be settable by the user (and scoped higher) but this suffices for now
  			var paddingX = 6;
  			var paddingY = 6;
  
  			var contentWidth = node.getWidth();
  			var contentHeight = node.getHeight();
  			var boxWidth = contentWidth + paddingX;
  			var boxHeight = contentHeight + paddingY;
  
  			// clear background
  			ctx.clearRect(s.x - boxWidth/2, s.y - boxHeight/2, boxWidth, boxHeight);
  
  			// fill background
  			if (selected !== null && selected.node !== null && selected.node.id === node.id) {
  				ctx.fillStyle = "#FFFFE0";
  			} else if (nearest !== null && nearest.node !== null && nearest.node.id === node.id) {
  				ctx.fillStyle = "#EEEEEE";
  			} else {
  				ctx.fillStyle = "#FFFFFF";
  			}
  			ctx.fillRect(s.x - boxWidth/2, s.y - boxHeight/2, boxWidth, boxHeight);
  
  			if (node.data.image == undefined) {
  				ctx.textAlign = "left";
  				ctx.textBaseline = "top";
  				ctx.font = (node.data.font !== undefined) ? node.data.font : nodeFont;
  				ctx.fillStyle = "#000000";
  				var text = (node.data.label !== undefined) ? node.data.label : node.id;
  				ctx.fillText(text, s.x - contentWidth/2, s.y - contentHeight/2);
  			} else {
  				// Currently we just ignore any labels if the image object is set. One might want to extend this logic to allow for both, or other composite nodes.
  				var src = node.data.image.src;  // There should probably be a sanity check here too, but un-src-ed images aren't exaclty a disaster.
  				if (src in nodeImages) {
  					if (nodeImages[src].loaded) {
  						// Our image is loaded, so it's safe to draw
  						ctx.drawImage(nodeImages[src].object, s.x - contentWidth/2, s.y - contentHeight/2, contentWidth, contentHeight);
  					}
  				}else{
  					// First time seeing an image with this src address, so add it to our set of image objects
  					// Note: we index images by their src to avoid making too many duplicates
  					nodeImages[src] = {};
  					var img = new Image();
  					nodeImages[src].object = img;
  					img.addEventListener("load", function () {
  						// HTMLImageElement objects are very finicky about being used before they are loaded, so we set a flag when it is done
  						nodeImages[src].loaded = true;
  					});
  					img.src = src;
  				}
  			}
  			ctx.restore();
  		}
  	);
  
  	renderer.start();
  
  	// helpers for figuring out where to draw arrows
  	function intersect_line_line(p1, p2, p3, p4) {
  		var denom = ((p4.y - p3.y)*(p2.x - p1.x) - (p4.x - p3.x)*(p2.y - p1.y));
  
  		// lines are parallel
  		if (denom === 0) {
  			return false;
  		}
  
  		var ua = ((p4.x - p3.x)*(p1.y - p3.y) - (p4.y - p3.y)*(p1.x - p3.x)) / denom;
  		var ub = ((p2.x - p1.x)*(p1.y - p3.y) - (p2.y - p1.y)*(p1.x - p3.x)) / denom;
  
  		if (ua < 0 || ua > 1 || ub < 0 || ub > 1) {
  			return false;
  		}
  
  		return new Springy.Vector(p1.x + ua * (p2.x - p1.x), p1.y + ua * (p2.y - p1.y));
  	}
  
  	function intersect_line_box(p1, p2, p3, w, h) {
  		var tl = {x: p3.x, y: p3.y};
  		var tr = {x: p3.x + w, y: p3.y};
  		var bl = {x: p3.x, y: p3.y + h};
  		var br = {x: p3.x + w, y: p3.y + h};
  
  		var result;
  		if (result = intersect_line_line(p1, p2, tl, tr)) { return result; } // top
  		if (result = intersect_line_line(p1, p2, tr, br)) { return result; } // right
  		if (result = intersect_line_line(p1, p2, br, bl)) { return result; } // bottom
  		if (result = intersect_line_line(p1, p2, bl, tl)) { return result; } // left
  
  		return false;
  	}
  
  	return this;
  }
  
  })();
  