added verarbeitung and output to main program

das ist eine erste variante des programms mit den teilen der anderen gruppen, damit sie es zum testen benutzen können

assets/cn.js

+/**
+* creates a new zoom behavior
+*/
+var zoom = d3.zoom().on("zoom", handle_zoom);
+
+/**
+* creates svg object and associated attributes
+* applies the zoom behavior to svg
+*/
+var svg = d3.select("svg.graph")
+    .call(zoom),
+width = svg.attr("width"),
+height = svg.attr("height"),
+perc;
+
+/**
+* scale functions that return y coordinate/color of node depending on group
+*/
+var color = d3.scaleOrdinal()
+    .domain(["height", "input", "depth"])
+    .range([' #01d7c0', ' #8b90fe ', '  #a15eb2 ']),
+y_scale = d3.scaleOrdinal()
+    .domain(["height", "input", "depth"])
+    .range([0, 200, 400]),
+to_remove;
+
+/**
+* creates node object and (default) radius
+*/
+var node,
+r = 10;
+
+/**
+* creates link object
+*/
+var link;
+
+/**
+* creates a background with a click functionality
+*/
+var rect = svg.append("rect")
+    .attr("x", 0)
+    .attr("y", 0)
+    .attr("height", height)
+    .attr("width", width)
+    .style("fill", 'white')
+    .on('click', click_rect);
+
+/**
+* creates svg object (legend) and associated attributes
+*/
+var svg_legend = d3.select("svg.legendsvg"),
+legend_position = [65,95,125],
+arrow_legend_position = [0,25],
+arrow_group_names = ["citation","self-citation"],
+group_names = ["cited by","input","reference"],
+line_type = d3.scaleOrdinal()
+    .domain(["line","dotted"])
+    .range([("8,0"),("8,8")]),
+text_info = '',
+text_abstract = '';
+    
+var legend = svg_legend.selectAll(".legend")
+    .data(legend_position)
+    .enter()
+    .append("g")
+    .attr("class","legend")
+    .attr("transform", function(d,i) {return "translate(0," + d  + ")"; });
+    
+legend.append("text")
+    .attr("x", 80)
+    .attr("y", 0)
+    .attr("dy", ".35em")
+    .style("text-anchor", "start")
+    .text(function(d,i) {return group_names[i]});
+    
+legend.append("circle")
+    .attr("r", r)
+    .attr("cx",30-r)
+    .style("fill", color);
+        
+var legend_arrow = svg_legend.selectAll(".legendarr")
+    .data(arrow_legend_position)
+    .enter()
+    .append("g")
+    .attr("class","legendarr")
+    .attr("transform", function(d) { return "translate(0," + d  + ")"; });
+    
+legend_arrow.append("line")
+    .attr("x1", 10)
+    .attr("x2", 50)
+    .attr("y1", 10)
+    .attr("y2", 10)
+    .style("stroke-dasharray",line_type)
+    .style("stroke", '#999')
+    .style("stroke-width", "1px")
+    .style('pointer-events', 'none')
+    .attr('marker-end',update_marker('#999',this));
+
+legend_arrow.append("text")
+    .attr("x", 80)
+    .attr("y", 10)
+    .attr("dy", ".35em")
+    .style("text-anchor", "start")
+    .text(function(d,i){return arrow_group_names[i]});
+
+/**
+* creates a new simulation
+* updates the positions of the links and nodes when the 
+  state of the layout has changed (simulation has advanced by a tick)
+*/
+var simulation = d3.forceSimulation()
+    .force("link", d3.forceLink().id(function(d) {return d.doi;}).distance(50).strength(function(d) {
+            if (d.group == "input") {return 0;}
+            else {return 5;}
+        }))
+        .force("collide", d3.forceCollide(function(d) {
+            if (d.group == "input") {return 100;}
+            else {return 65;}
+        }).strength(0.5))
+    .force("charge", d3.forceManyBody().strength(0.001))
+    .force("center", d3.forceCenter(width/2, height/2+20))
+    .force("yscale", d3.forceY().strength(function(d) {
+        if (d.group == "input") {return 1000;}
+        else {return 50;}
+    }).y(function(d) {return y_scale(d.group)}))
+    .alpha(0.005)
+    .on("end",  zoom_to);
+
+/**
+* creates group element
+*/
+var g = svg.append("g")
+    .attr("class", "everything")
+
+/**
+* loads JSON data and calls the update function
+*/
+d3.json("json_text.json").then(function(graph) {
+    update(graph.links, graph.nodes);
+})
+
+/**
+* calls update functions for links and nodes
+* adds the nodes, links and tick functionality to the simulation
+* @param {object} nodes - nodes
+* @param {object} links - links
+*/
+function update(links, nodes) {
+    update_links(links);
+    update_nodes(nodes);
+    
+    simulation
+        .nodes(nodes)
+        .on("tick", handle_tick);
+    simulation.force("link")
+        .links(links);
+    
+    link.attr('marker-end', function(d) {return update_marker("#999", d.target);})
+        .style("stroke-dasharray",function(d){return self_citation(d.source,d.target)? ("8,8"): ("1,0")});
+}
+
+/**
+* initializes and shows links
+* @param {object} links - links
+*/
+function update_links(links) {
+    link = g.append("g")
+        .selectAll(".link")
+        .data(links)
+        .enter()
+        .append("line")
+        .style("stroke-width", "1px")
+        .style("stroke", "#999")
+        .attr("class", "link");
+}
+
+/**
+* initializes and shows nodes with circles, texts and a click functionality
+* creates a new drag behavior and applies it to the circles
+* @param {object} nodes - nodes
+*/
+function update_nodes(nodes) {
+    node = g.selectAll(".node")
+        .data(nodes)
+        .enter()
+        .append("g")
+        .attr("class", "node")
+        .call(d3.drag()
+            .on("start", start_drag)
+            .on("drag", dragged)
+        );
+
+    node.append("circle")
+        .attr("class", "circle")
+        .attr("r", function(d) {return 1.5*r+d.citations*0.05})
+        .style("fill", function(d){ return color(d.group)})
+        .on('click', click_node);
+
+    node.append("text")
+        .attr("class", "text") 
+        .style("font-size", "15px")
+        .style('pointer-events', 'auto')
+        .text(function (d) {const first_author=d.author[0].split(" ")
+        return first_author[first_author.length-1];})
+        .on('click', click_node);
+}
+
+/**
+* creates arrowhead and returns its url
+* @param {string} color - color of arrowhead
+* @param {string} target - target node
+*/
+function update_marker(color, target) {
+    var radius = 1.5*r+target.citations*0.05;
+    svg.append('defs').append('marker')
+        .attr('id',color.replace("#", "")+radius)
+        .attr('viewBox','-0 -5 10 10')
+        .attr('refX',radius+9.5)
+        .attr('refY',0)
+        .attr('orient','auto')
+        .attr('markerWidth',10)
+        .attr('markerHeight',15)
+        .attr('xoverflow','visible')
+        .append('svg:path')
+        .attr('d', 'M 0,-5 L 10 ,0 L 0,5')
+        .attr('fill', color)
+        .style('stroke','none');
+    return "url(" + color + radius + ")";
+};
+
+/**
+* sets color of circle and its links to black and removes the previous highlights
+* displays overview info of node in textbox
+* @param {object} node - node
+*/
+function click_node(node) {
+    d3.select(this.parentNode).raise();
+    fix_nodes(node);
+    if(to_remove){
+        d3.select(to_remove).selectAll(".circle").style("stroke","none")
+    }
+    to_remove = this.parentNode;
+    d3.select(this.parentNode).selectAll(".circle").style("stroke","black")
+    mark_link(node)
+    textbox_content(node)
+    reset_button_highlight()
+    highlight_button("overview")
+}
+
+/**
+* removes the highlights of the circles and their links
+*/
+function click_rect() {
+    fix_nodes(node);
+    d3.selectAll(".circle").style("stroke", "none")
+    d3.selectAll(".link")
+        .style("stroke", "#999")
+        .attr('marker-end', function(d) {return update_marker('#999', d.target);})
+    text_abstract='';
+    text_info='';
+    reset_button_highlight()
+    document.getElementById('textbox').innerHTML = "Click node";
+}
+
+/**
+* returns true if journals have a common author (self-citation)
+* @param {object} source - node
+* @param {object} target - node
+*/
+function self_citation(source,target) {
+    return source.author.some(item=>target.author.includes(item))
+}
+
+/**
+* sets color of link (line and arrowhead) to black if it is directly connected to node
+* and to grey otherwise
+* @param {object} node - node
+*/
+function mark_link(node) {
+    d3.selectAll(".link")
+        .style("stroke", function(o) {
+            return is_link_for_node(node, o) ? "black" : "#999";})
+        .attr('marker-end', function(o) {
+            return is_link_for_node(node, o) ? update_marker('#000000', o.target) : update_marker('#999', o.target);})
+}
+
+/**
+* returns true if link is directly connected to node and false if it is not
+* @param {object} node - node
+* @param {object} link - link
+*/
+function is_link_for_node(node, link) {
+    return link.source.index == node.index || link.target.index == node.index;
+}
+
+/**
+* saves text for overview and abstract of node
+* outputs node info to textbox
+* @param {object} node - node
+*/
+function textbox_content(node) {
+    text_info = "Title:" + '</br>' + node.name +
+    '</br>' +'</br>'+"Author:"+ '</br>' +node.author+'</br>'+'</br>'+"Date:"+'</br>'
+    +node.year+'</br>'+'</br>'+"Journal:"+'</br>'+node.journal+'</br>'+'</br>'+"doi:"
+    +'</br>'+'<a href="'+node.doi+ '">'+node.doi+'</a>'+'</br>'+'</br>'+"Citations:"
+    +'</br>'+node.citations;
+    text_abstract = node.abstract;
+    document.getElementById('textbox').innerHTML = text_info;
+}
+
+/**
+* sets color of btn to dark gray
+* @param {object} btn - button
+*/
+function highlight_button(btn) {
+    reset_button_highlight();
+    document.getElementById(btn).style.background = "#CACACA";
+}
+
+/**
+* sets color of all buttons to default light gray
+*/
+function reset_button_highlight() {
+    document.getElementById("overview").style.background = '';
+    document.getElementById("abstract").style.background = '';
+}
+
+/**
+* displays abstract in textbox if a is true, overview text otherwise
+* @param {bool} a- bool
+*/
+function display_abstract(a) {
+    if (text_abstract == '' && text_info == '') {
+        document.getElementById('textbox').innerHTML="Click node";
+    }
+    else {
+        if (a == true) {
+            document.getElementById('textbox').innerHTML = text_abstract;
+        }
+        else {
+            document.getElementById('textbox').innerHTML = text_info;
+        }
+    }   
+}
+
+/**
+* updates the positions of the links and nodes
+*/
+function handle_tick() {
+    link.attr("x1", function (d) {return d.source.x;})
+        .attr("y1", function (d) {return d.source.y;})
+        .attr("x2", function (d) {return d.target.x;})
+        .attr("y2", function (d) {return d.target.y;});
+    node.attr("transform", function (d) {return "translate(" + d.x + ", " + d.y + ")";});
+}
+
+/**
+* initializes the dragging of the node
+* @param {object} node - node
+*/
+function start_drag(node) {
+    d3.select(this).raise();
+    if (!d3.event.active) 
+        simulation.alphaTarget(0.3).restart()
+    node.fx = node.x;
+    node.fy = node.y;
+    fix_nodes(node);
+}
+
+/**
+* applies the dragging to the node
+* @param {object} node - node
+*/
+function dragged(node) {
+    node.fx = d3.event.x;
+    node.fy = d3.event.y;
+    fix_nodes(node);
+}
+
+/**
+* fix positions of all nodes except for the current node
+* @param {object} this_node - node
+*/
+function fix_nodes(this_node) {
+    node.each(function(d) {
+      if (this_node != d) {
+        d.fx = d.x;
+        d.fy = d.y;
+      }
+    });
+}
+
+/**
+* applies the transformation (zooming or dragging) to the g element
+*/
+function handle_zoom() {
+    d3.select('g').attr("transform", d3.event.transform);
+}
+
+/**
+* transforms svg so that the zoom is adapted to the size of the graph
+*/
+function zoom_to() {
+    node_bounds = d3.selectAll("svg.graph").node().getBBox();
+    svg_bounds = d3.select("rect").node().getBBox();
+
+    perc_x = width/(node_bounds.width+100);
+    perc_y = height/(node_bounds.height+100);
+    perc = d3.min([perc_x, perc_y])
+    
+    d3.select('svg')
+		.call(zoom.scaleBy, perc);
+}
+
+/**
+* transforms svg so that the zoom and drag is reset
+*/
+function reset_view() {
+    d3.select('svg')
+        .call(zoom.scaleTo, 1)
+    d3.select('svg')
+        .call(zoom.translateTo, 0.5 * width, 0.5 * height);
+    d3.select('svg')
+		.call(zoom.scaleBy, perc);
+}
+
+/**
+* save svg as png
+*/
+function save_svg(){
+	var svgString = get_svg_string(svg.node());
+	svg_string_to_image(svgString, 2*width, 2*height, 'png', save); // passes Blob and filesize String to the callback
+
+	function save( dataBlob, filesize ){
+		saveAs(dataBlob, 'D3 vis exported to PNG.png'); // FileSaver.js function
+	}
+};
+
+/**
+* generate svgString
+* @param {object} svgNode - node
+*/
+function get_svg_string(svgNode) {
+	svgNode.setAttribute('xlink', 'http://www.w3.org/1999/xlink');
+	var cssStyleText = get_css_styles(svgNode);
+	append_css(cssStyleText, svgNode);
+
+	var serializer = new XMLSerializer();
+	var svgString = serializer.serializeToString(svgNode);
+	svgString = svgString.replace(/(\w+)?:?xlink=/g, 'xmlns:xlink='); // Fix root xlink without namespace
+	svgString = svgString.replace(/NS\d+:href/g, 'xlink:href'); // Safari NS namespace fix
+
+	return svgString;
+
+	function get_css_styles(parentElement) {
+		var selectorTextArr = [];
+
+		// Add Parent element Id and Classes to the list
+		selectorTextArr.push('#' + parentElement.id);
+		for (var c = 0; c < parentElement.classList.length; c++)
+				if (!contains('.'+parentElement.classList[c], selectorTextArr))
+					selectorTextArr.push('.'+parentElement.classList[c]);
+
+		// Add Children element Ids and Classes to the list
+		var nodes = parentElement.getElementsByTagName("*");
+		for (var i = 0; i < nodes.length; i++) {
+			var id = nodes[i].id;
+			if (!contains('#'+id, selectorTextArr))
+				selectorTextArr.push('#' + id);
+
+			var classes = nodes[i].classList;
+			for (var c = 0; c < classes.length; c++)
+				if (!contains('.'+classes[c], selectorTextArr))
+					selectorTextArr.push('.'+classes[c]);
+		}
+
+		// Extract CSS Rules
+		var extractedCSSText = "";
+		for (var i = 0; i < document.styleSheets.length; i++) {
+			var s = document.styleSheets[i];
+			
+			try {
+			    if(!s.cssRules) continue;
+			} catch(e) {
+		    		if(e.name !== 'SecurityError') throw e; // for Firefox
+		    		continue;
+		    	}
+
+			var cssRules = s.cssRules;
+			for (var r = 0; r < cssRules.length; r++) {
+				if (contains(cssRules[r].selectorText, selectorTextArr))
+					extractedCSSText += cssRules[r].cssText;
+			}
+		}
+		
+
+		return extractedCSSText;
+
+		function contains(str,arr) {
+			return arr.indexOf(str) === -1 ? false : true;
+		}
+
+	}
+
+	function append_css(cssText, element) {
+		var styleElement = document.createElement("style");
+		styleElement.setAttribute("type","text/css"); 
+		styleElement.innerHTML = cssText;
+		var refNode = element.hasChildNodes() ? element.children[0] : null;
+		element.insertBefore(styleElement, refNode);
+	}
+}
+
+/**
+* convert svgString to image and export it
+* @param {object} svgString - svgString
+* @param {object} width - width of image
+* @param {object} height - height of image
+* @param {object} format - format to save image in 
+* @param {object} callback - callback function 
+*/
+function svg_string_to_image( svgString, width, height, format, callback ) {
+	var format = format ? format : 'png';
+
+	var imgsrc = 'data:image/svg+xml;base64,'+ btoa(unescape(encodeURIComponent(svgString))); // Convert SVG string to data URL
+
+	var canvas = document.createElement("canvas");
+	var context = canvas.getContext("2d");
+
+	canvas.width = width;
+	canvas.height = height;
+
+	var image = new Image();
+	image.onload = function() {
+		context.clearRect(0, 0, width, height);
+		context.drawImage(image, 0, 0, width, height);
+
+		canvas.toBlob(function(blob) {
+			var filesize = Math.round(blob.length/1024) + ' KB';
+			if (callback) callback(blob, filesize);
+		});
+		
+	};
+
+	image.src = imgsrc;
+}
+