jquery.connections.js

(function($) {
	$.fn.connections = function(options) {
		if (options === 'update') {
			return processConnections(update, this);
		} else if (options === 'remove') {
			return processConnections(destroy, this);
		} else {
			options = $.extend(true, {
				borderClasses: {},
				'class': 'connection',
				css: {
					border: '3px solid red'
				},
				from: this,
				tag: 'connection',
				to: this,
				within: ':root'
			}, options);
			connect(options);
			return this;
		}
	};

	$.event.special.connections = {
		teardown: function(namespaces) {
			processConnections(destroy, $(this));
		}
	}

	var connect = function(options) {
		var borderClasses = options.borderClasses;
		var tag = options.tag;
		var end1 = $(options.from);
		var end2 = $(options.to);
		var within = $(options.within);
		delete options.borderClasses;
		delete options.tag;
		delete options.from;
		delete options.to;
		delete options.within;
		within.each(function() {
			var container = this;
			var done = new Array();
			end1.each(function() {
				var node = this;
				done.push(this);
				end2.not(done).each(function() {
					createConnection(container, [node, this], tag, borderClasses, options);
				});
			});
		});
	};

	var createConnection = function(container, nodes, tag, borderClasses, options) {
		var css = $.extend({ position: 'absolute' }, options.css);
		var connection = $('<' + tag + '/>', options).css(css);
		connection.appendTo(container);

		var border_w = (connection.outerWidth() - connection.innerWidth()) / 2;
		var border_h = (connection.outerHeight() - connection.innerHeight()) / 2;

		if (border_w <= 0 && border_h <= 0) {
			border_w = border_h = 1;
		}

		var data = {
			borderClasses: borderClasses,
			border_h: border_h,
			border_w: border_w,
			node_from: $(nodes[0]),
			node_to: $(nodes[1]),
			nodes_dom: nodes,
			css: css
		}

		if ('none' === connection.css('border-top-style')) {
			data.css.borderStyle = 'solid';
		}
		$.data(connection.get(0), 'connection', data);
		$.data(connection.get(0), 'connections', [connection.get(0)]);
		for (var i = 0; i < 2; i++) {
			var connections = connection.add($.data(nodes[i], 'connections')).get();
			$.data(nodes[i], 'connections', connections);
			if (connections.length == 1) {
				$(nodes[i]).on('connections.connections', false);
			}
		}
		update(connection.get(0));
	};

	var destroy = function(connection) {
		var nodes = $.data(connection, 'connection').nodes_dom;
		for (var i = 0; i < 2; i++) {
			var connections = $($.data(nodes[i], 'connections')).not(connection).get();
			$.data(nodes[i], 'connections', connections);
		}
		$(connection).remove();
	};

	var getState = function(data) {
		data.rect_from = data.nodes_dom[0].getBoundingClientRect();
		data.rect_to = data.nodes_dom[1].getBoundingClientRect();
		var cached = data.cache;
		data.cache = [
			data.rect_from.top, data.rect_from.right, data.rect_from.bottom, data.rect_from.left,
			data.rect_to.top, data.rect_to.right, data.rect_to.bottom, data.rect_to.left
		];
		data.hidden = (0 === (data.cache[0] | data.cache[1] | data.cache[2] | data.cache[3])) ||
					(0 === (data.cache[4] | data.cache[5] | data.cache[6] | data.cache[7]));
		data.unmodified = true;
		if (cached === undefined) {
			return data.unmodified = false;
		}
		for (var i = 0; i < 8; i++) {
			if (cached[i] !== data.cache[i]) {
				return data.unmodified = false;
			}
		}
	}

	var update = function(connection) {
		var data = $.data(connection, 'connection');
		getState(data);
		if (data.unmodified) {
			return;
		}
		var border_h = data.border_h;
		var border_w = data.border_w;
		var from_node = data.node_from;
		var to_node = data.node_to;
		var from = data.rect_from;
		var to = data.rect_to;
		var b = (from.bottom + from.top) / 2;
		var r = (to.left + to.right) / 2;
		var t = (to.bottom + to.top) / 2;
		var l = (from.left + from.right) / 2;

		var h = ['right', 'left'];
		if (l > r) {
			h = h.reverse();
			var x = Math.max(r - border_w / 2, Math.min(from.right, to.right));
			r = l + border_w / 2;
			l = x;
		} else {
			l -= border_w / 2;
			r = Math.min(r + border_w / 2, Math.max(from.left, to.left));
		}
		var v = ['bottom', 'top'];
		if (t > b) {
			v = v.reverse();
			var x = Math.max(b - border_h / 2, Math.min(from.bottom, to.bottom));
			b = t + border_h / 2;
			t = x;
		} else {
			b = Math.min(b, Math.max(from.top, to.top));
			t -= border_h / 2;
		}
		var width = r - l;
		var height = b - t;
		if (width < border_w) {
			t = Math.max(t, Math.min(from.bottom, to.bottom));
			b = Math.min(b, Math.max(from.top, to.top));
			l = Math.max(from.left, to.left);
			r = Math.min(from.right, to.right);
			r = l = (l + r - border_w) / 2;
		}
		if (height < border_h) {
			l = Math.max(l, Math.min(from.right, to.right));
			r = Math.min(r, Math.max(from.left, to.left));
			t = Math.max(from.top, to.top);
			b = Math.min(from.bottom, to.bottom);
			b = t = (t + b - border_h) / 2;
		}
		width = r - l;
		height = b - t;
		width <= 0 && (border_h = 0);
		height <= 0 && (border_w = 0);
		var style =
				'border-' + v[0] + '-' + h[0] + '-radius: 0;' +
				'border-' + v[0] + '-' + h[1] + '-radius: 0;' +
				'border-' + v[1] + '-' + h[0] + '-radius: 0;';
		(border_h <= 0 || border_w <= 0) && (style += 'border-' + v[1] + '-' + h[1] + '-radius: 0;');
		if (data.hidden) {
			style += 'display: none;';
		} else {
			data.css['border-' + v[0] + '-width'] = 0;
			data.css['border-' + h[0] + '-width'] = 0;
			data.css['border-' + v[1] + '-width'] = border_h;
			data.css['border-' + h[1] + '-width'] = border_w;
			var current_rect = connection.getBoundingClientRect();
			data.css.left = connection.offsetLeft + l - current_rect.left;
			data.css.top = connection.offsetTop + t - current_rect.top;
			data.css.width = width - border_w;
			data.css.height = height - border_h;
		}
		var bc = data.borderClasses;
		$(connection).
				removeClass(bc[v[0]]).removeClass(bc[h[0]]).
				addClass(bc[v[1]]).addClass(bc[h[1]]).
				attr('style', style).
				css(data.css);
	}

	var processConnections = function(method, elements) {
		return elements.each(function() {
			var connections = $.data(this, 'connections');
			if (connections instanceof Array) {
				for (var i = 0, len = connections.length; i < len; i++) {
					method(connections[i]);
				}
			}
		});
	};
})(jQuery);