MediaWiki:Network-graph.js: Difference between revisions

Revision as of 12:50, 24 June 2019

/*

Name:		MediaWiki:Network-graph.js
Purpose:	Build the network graph for the page being displayed
Parameters:	title = the internal title of the reference (e.g., Cerebral_hemispheric_lateralization_in_cardiac_autonomic_control)
		depth = the number of levels to include in the graph (1 - 9)
Author:		Alan O'Neill
Release Date:	June 20, 2019

*/

var Ctrl = {
	canvas: {
		width:		$(window).width(),
		height:		$(window).width(),
		borderColor:	'black',
		borderWidth:	'1px'
	},

	color: [
		'#e6194B',	// red
		'#f58231',	// orange
		'#ffe119',	// yellow
		'#3cb44b',	// green
		'#42d4f4',	// cyan
		'#4363d8',	// blue
		'#000075',	// navy
		'#f032e6',	// magenta
		'#800000',	// maroon
		'#9A6324',	// brown
	],

	circle: {
		radius:		14,
		textXOffset:	-4,
		textYOffset:	4,
		fontSize:	'12px',
		fontColor:	'white',
		fontWeight:	'bold',
	},

	arrow: {
		size:		6,
		strokeWidth:	1,		// 0 = no arrow
		color:		'grey',
	},

	line: {
		strokeWidth:	2,
		color:		'grey',
	},

	physical: {
		charge:		-10,
		linkDistance:	10,
		distance:	120,
		gravity:	.01,
	},

	force:			null,
	svg:			null,
}

String.prototype.toTitleCase = function() {
	return this.replace(
		/\w\S*/g,
		function(txt) {
			return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase();
		}
	);
}

function getQuery(name) {
	// Return the value of a parameter in the query string
	// name - the name in the name/value pair

	var value = '';
	var query = window.location.search.substring(1).split('&');
	for (var i = 0; i < query.length; i++) {
		var nv = query[i].split('=');
		if (nv[0] == name) {
			value = nv[1];
			break;
		}
	}

	return value;
}

function getBaseUrl() {
	// Return the base URL for the site (e.g., 'https://testtestsudepwiki.pathologyjhmi.edu')

	var baseUrl = location.protocol + '//' + location.host + location.pathname;
	var i = baseUrl.indexOf('/index.php');
	if (i < 0) { i = baseUrl.indexOf('/site-links'); }
	baseUrl = baseUrl.substr(0, i);

	return baseUrl;
}

function getTitle() {
	// Return the title of the article from the URL

	var title = getQuery('title');
	if (title.length == 0) {
		var delim = '/index.php/';
		title = location.pathname.substr(location.pathname.indexOf(delim) + delim.length); // e.g., Cerebral_hemispheric_lateralization_in_cardiac_autonomic_control
	}

	return title;
}

function getDepth() {
	// Return the depth to use for the graph (?)

	return 9;
}

function tickHandler() {
	Ctrl.svg
		.selectAll('.link')
		.attr('x1', function(link) { return link.source.x; })
		.attr('y1', function(link) { return link.source.y; })
		.attr('x2', function(link) { return link.target.x; })
		.attr('y2', function(link) { return link.target.y; });

	Ctrl.svg
		.selectAll('.node')
		.attr('transform', function(node) { return 'translate(' + node.x + ',' + node.y + ')'; });
}

function gotoPage(node, index) {
	// Go to the page associated with a node
	// node - the node that was double clicked (object)
	// index - the index of the node that was double clicked

	// When node.level is zero, the node refers to the page being displayed
	if (node.level > 0) {
		window.location.href = getBaseUrl() + '/index.php/' + node.name;
	} else {
		alert("You're already viewing this page.");
	}
};

function main() {
	var title = getTitle();
	var depth = getDepth();

	if (depth < 1) { depth = 1; }
	else if (depth > 9) { depth = 9; }

	// Create the canvas
	Ctrl.svg = d3.select('#network-graph')
		.append('svg')
		.attr('width', Ctrl.canvas.width)
		.attr('height', Ctrl.canvas.height);

	// Define the arrow head
	for (var level = 0; level < depth; level++ ) {
		let fullSize = Ctrl.arrow.size;
		let halfSize = Math.floor(fullSize / 2);
		Ctrl.svg
			.append('defs')
			.selectAll('marker')
			.data(['arrow' + level])
			.enter()
			.append('marker')
			.attr('id', function(node, index) { return node; }) // e.g., 'arrow0'
			.attr('viewBox', '0 -' + halfSize + ' ' + fullSize + ' ' + fullSize)
			.attr('refX', function(node, index) { return Math.floor(Ctrl.circle.radius / 2) + Ctrl.arrow.size; })
			.attr('refY', 0)
			.attr('markerWidth', fullSize)
			.attr('markerHeight', fullSize)
			.attr('orient', 'auto')
			.append('path')
			.attr('d', function(node, index) { return 'M0,-' + halfSize + 'L' + fullSize + ',0L0,' + halfSize + 'L' + fullSize + ',0L0,-' + halfSize; })
			.style('stroke', Ctrl.arrow.color)
			.style('stroke-width', Ctrl.arrow.strokeWidth)
	}

	// Define the characteristics of the force simulation
	Ctrl.force = d3.layout
		.force()
		.size([Ctrl.canvas.width, Ctrl.canvas.height])
		.charge(Ctrl.physical.charge)
		.linkDistance(Ctrl.physical.linkDistance)
		.distance(Ctrl.physical.distance)
		.gravity(Ctrl.physical.gravity);

	// Read the data and use it to build the graph
	var url = getBaseUrl() + '/site-links/network-graph.php?depth=' + depth + '&title=' + title;
	d3.json(url, function(json) {
		if (json) {
			// Introduce the data to the force simulation
			Ctrl.force
				.nodes(json.nodes)
				.links(json.links);

			// Add the links (lines and arrows)
			Ctrl.svg
				.selectAll('.link')
				.data(json.links)
				.enter()
				.append('line')
				.attr('class', 'link')
				.style('stroke', Ctrl.line.color)
				.style('stroke-width', Ctrl.line.strokeWidth)
				.style('marker-end',  function(node, index) { return 'url(#arrow0)'; }); //return 'url(#arrow' + node.level + ')'; });

			// Add the nodes (circles)
			Ctrl.svg
				.selectAll('.node')
				.data(json.nodes)
				.enter()
				.append('g')
				.attr('class', 'node')
				.on('dblclick', gotoPage)
				.append('circle')
				.attr('r', Ctrl.circle.radius)
				.style('fill', function(node, index) { return Ctrl.color[node.level]; })
				.call(Ctrl.force.drag);

			// Add a title to each node
			Ctrl.svg
				.selectAll('circle')
				.append('title')
				.text(function(node, index) {
					var title = node.name.replace(/_/g, ' ').toTitleCase();
					if (node.level == 0) { title += ' (this page)'; }
					return title;
				});

			// Add the level number to each node
			Ctrl.svg
				.selectAll('.node')
				.append('text')
				.attr('dx', Ctrl.circle.textXOffset)
				.attr('dy', Ctrl.circle.textYOffset)
				.text(function(node, index) { return node.level; })
				.style('font-size', Ctrl.circle.fontSize)
				.style('fill', Ctrl.circle.fontColor)
				.style('font-weight', Ctrl.circle.fontWeight);

			// Draw a border around the graph
			Ctrl.svg.append('rect')
				.attr('x', 0)
				.attr('y', 0)
				.attr('height', Ctrl.canvas.height)
				.attr('width', Ctrl.canvas.width)
				.style('stroke', Ctrl.canvas.borderColor)
				.style('fill', 'none')
				.style('stroke-width', Ctrl.canvas.borderWidth);

			// Set up the tick handler
			Ctrl.force.on('tick', function() { tickHandler(); });

			// Start the force simulation
			Ctrl.force.start();
			$('#loadNetworkGraph').html('Hover over a node to see the title of the article.  Double-click on a node to view the article.');
		} else {
			$('#loadNetworkGraph').html('No data is available for this graph.');
		}
	});
}

$(document).ready(function() { main(); });