Graph-Editor/editor.html at master · achiever202/Graph-Editor · GitHub

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<html>

<head>
	<title>Graph Editor</title>
	<link rel="stylesheet" type="text/css" href="assignment3.css">
</head>

<body>

	<h1 id="header">Graph Editor Interface</h1>

	<p>
		<!-- This division contains the canvas for drawing. -->
		<div id="canvas_division">
			<canvas id="graph" width=600 height=600>
			</canvas>
		</div>
		<!-- This division contains the form with radio buttons for different modes in the user interface -->
		<div id="modes">
			<form class = "radio_buttons">
				<input type="radio" name="Modes" id="add_vertex" value="add_vertices" checked onchange="canvasRedraw()">Add Vertices<br>
				<input type="radio" name="Modes" id="add_edge" value="add_edges" onchange="canvasRedraw()">Add Edges<br>
				<input type="radio" name="Modes" id="move_vertex" value="move_vertices" onchange="canvasRedraw()">Move Vertices<br>
				<input type="radio" name="Modes" id="delete_vertex" value="delete_vertices" onchange="canvasRedraw()">Delete Vertices<br>
				<input type="radio" name="Modes" id="delete_edge" value="delete_edges" onchange="canvasRedraw()">Delete Edges<br>
				<input type="radio" name="Modes" id="path" value="shortest_path" onchange="canvasRedraw()">Shortest Path<br>
				<input type="radio" name="Modes" id="mst" value="spanning_tree" onchange="minimumSpanningTree()">Minimum Spanning Tree<br>
			</form>
			<div id="save">
				<br><br><br>Save the current graph:<br>
				<input id="save_bar" type="text" name="file">
				<input id="save_button" type="button" value="Save" onclick="saveGraph()">
			</div>

			<div id="load">
				<br><br><br>Load Graph from file:<br>
				<select id="files" size="5" style="background-color:grey;color:white;width:200px">
				</select>
				<br>
				<input id="load_button" type="button" value="Load" onclick="loadGraph()">
				<input id="clear" type="button" value="Clear Canvas" onclick="clearGraph()">

			</div>
		</div>

	</p>
	<script>

		/* graph_canvas is the canvas object.
		 * canvas_left stores the left offset of the canvas.
		 * canvas_top stores the top offset of the canvas.
		 * vertices stores the vertices of the graph.
		 * edges stores the edges in the graph.
		 */
		var graph_canvas = document.getElementById('graph'),
			canvas_left = graph_canvas.offsetLeft,
			canvas_top = graph_canvas.offsetTop,
			vertices = new Array(),
			edges = new Array(),
			last_clicked = 1,
			n = 0,
			last_selected = 0
			vertex_radius = 12;

		// This function draws the circle.
		function drawCircle(x, y, colour)
		{
			var context = graph_canvas.getContext('2d');
			context.beginPath();
			context.fillStyle = colour;
			context.strokeStyle = "#000000";
			context.strokeWidth = 1;
			context.arc(x, y, vertex_radius, 0, Math.PI*2);
			context.closePath();
			context.fill();
			context.stroke();
		}

		// This function draws a line.
		function drawLine(sx, sy, ex, ey, colour)
		{
			var context = graph_canvas.getContext('2d');
			context.beginPath();
			context.strokeStyle = colour;
			context.lineWidth = 3;
			context.fillStyle = colour;
			context.moveTo(sx, sy);
			context.lineTo(ex, ey);
			context.closePath();
			context.fill();
			context.stroke();
		}

		// This function checks whether a point is a vertex or not.
		function isVertex(point)
		{
			for(i=0; i<vertices.length; i++)
			{
				var distance = (vertices[i].x-point.x)*(vertices[i].x-point.x) + (vertices[i].y-point.y)*(vertices[i].y-point.y);
				if(distance<=vertex_radius*vertex_radius)
					break;
			}
			return i;
		}

		// This function redraws the canvas with the current edges and vertices.
		function canvasRedraw()
		{
			context = graph_canvas.getContext('2d');
			context.clearRect(0,0,600,600);

			for(i=0; i<edges.length; i++)
				drawLine(vertices[edges[i].start].x, vertices[edges[i].start].y, vertices[edges[i].end].x, vertices[edges[i].end].y, "#000000");

			for(i=0; i<vertices.length; i++)
				drawCircle(vertices[i].x, vertices[i].y, "#FF0000");
		}

		// This function redraws the canvas from the server data for shortest path and minimum spanning tree.
		function serverRedraw(edge_array)
		{
			context = graph_canvas.getContext('2d');
			context.clearRect(0,0,600,600);

			for(i=0; i<edges.length; i++)
				drawLine(vertices[edges[i].start].x, vertices[edges[i].start].y, vertices[edges[i].end].x, vertices[edges[i].end].y, "#000000");

			for(i=0; i<edge_array.length; i++)
			{
				drawLine(vertices[edge_array[i][0]].x, vertices[edge_array[i][0]].y, vertices[edge_array[i][1]].x, vertices[edge_array[i][1]].y, "#66CCCC");
			}

			for(i=0; i<vertices.length; i++)
				drawCircle(vertices[i].x, vertices[i].y, "#FF0000");
		}

		// This function returns the co-ordinates of the clicked point in the canvas.
		function clickedPoint(event)
		{
			var x, y;
			if(event.pageX || event.pageY)
			{
				x = event.pageX;
				y = event.pageY;
			}
			else
			{
				x = event.clientX + document.body.scrollLeft + document.documentElement.scrollLeft;
				y = event.clientY + document.body.scrollTop + document.documentElement.scrollTop;
			}

			x -= canvas_left;
			y -= canvas_top;

			var point = new Object();
			point.x = x;
			point.y = y;
			return point;
		}

		// This function draws a vertex in the canvas.
		function drawVertex(event)
		{
			last_clicked = 1;

			var point = clickedPoint(event);
			i = isVertex(point);
			if(i==vertices.length)
			{
				vertices.push(point);
				// drawing the vertex on the canvas.
				drawCircle(point.x, point.y, "#FF0000");
			}
		}

		// This function draws an edge.
		function drawEdge(event)
		{
			if(last_clicked==2)
			{
				last_clicked = 1;

				point = clickedPoint(event);
				var i = isVertex(point);
				if(i<vertices.length)
				{
					edge = new Object();
					edge.start = last_selected;
					edge.end = i;
					edges.push(edge);
					canvasRedraw();
				}
			}
			else
			{
				var i=0;
				point = clickedPoint(event);
				var i = isVertex(point);
				if(i<vertices.length)
				{
					last_selected = i;
					last_clicked = 2;
					drawCircle(vertices[last_selected].x, vertices[last_selected].y, "#FF00FF");
				}
			}
		}

		// This function moves the vertex on the canvas.
		function moveVertex(event)
		{
			point = clickedPoint(event);
			var i = isVertex(point);
			if(i<vertices.length)
			{
				last_clicked = 3;
				last_selected = i;
				drawCircle(vertices[i].x, vertices[i].y, "#FF00FF");
			}
		}

		// This function deletes the selected vertex.
		function deleteVertex(event)
		{
			point = clickedPoint(event);
			i = isVertex(point);
			if(i<vertices.length)
			{
				vertices.splice(i,1);
				var temp_edges = new Array();
				for(j=0; j<edges.length; j++)
				{
					if(!(edges[j].start==i || edges[j].end==i))
					{
						var temp = edges[j];
						if(temp.start>i)
							temp.start--;
						if(temp.end>i)
							temp.end--;
						temp_edges.push(temp);
					}
				}
				edges = temp_edges;
				canvasRedraw();
			}
		}

		// This function deletes the selected edge.
		function deleteEdge(event)
		{
			if(last_clicked==5)
			{
				last_clicked = 1;
				point = clickedPoint(event);
				i = isVertex(point);
				if(i<vertices.length)
				{
					for(j=0; j<edges.length; j++)
						if((edges[j].start==i && edges[j].end==last_selected)||(edges[j].start==last_selected && edges[j].end==i))
							break;

					if(j<edges.length)
						edges.splice(j, 1);
				}
				canvasRedraw();
			}
			else
			{
				canvasRedraw();
				point = clickedPoint(event);
				i = isVertex(point);
				if(i<vertices.length)
				{
					last_clicked = 5;
					last_selected = i;
					drawCircle(vertices[i].x, vertices[i].y, "#FF00FF");
				}
			}
		}

		// This function send the formatted data to the server for calculating shortest path and minimum spanning tree.
		function sendData(first, last)
		{
			// edge sends the data for each edge in the format start[0]:end[0],start[1]:end[1]...
			// weights sends the distance of each edge, comma separated
			var edge = "";
			var weights = "";
			var server_query = new XMLHttpRequest();

			// formatting data to be sent
			for(i=0; i<edges.length; i++)
			{
				edge += edges[i].start+":"+edges[i].end+",";
				weights += Math.floor(Math.sqrt((vertices[edges[i].start].x-vertices[edges[i].end].x)*(vertices[edges[i].start].x-vertices[edges[i].end].x) + (vertices[edges[i].start].y-vertices[edges[i].end].y)*(vertices[edges[i].start].y-vertices[edges[i].end].y)))+",";
			}

			// for minimum spanning tree, sending number of nodes, edges and their weights.
			if(first==-1)
			{
				server_query.open("POST", "minimum_spanning_tree.jsp", false);
				server_query.setRequestHeader("Content-type","application/x-www-form-urlencoded");
				server_query.send("node="+vertices.length+"&edges="+edge+"&weight="+weights);
				var server_reply = server_query.responseText;

				// parsing the received string to form two dimensional arrays of edges forming the spanning tree.
				server_reply = server_reply.split(",");
				edge_array = [];
				for(i=0; i<server_reply.length; i++)
				{
					temp_edge = server_reply[i].split(":");
					temp_edge[0] = parseInt(temp_edge[0]);
					temp_edge[1] = parseInt(temp_edge[1]);
					edge_array.push(temp_edge);
				}
				serverRedraw(edge_array);
			}

			// for shortest path, sending number of nodes, edges, weight, start and end index.
			else
			{
				// if there are no edges in the graph.
				if(edges.length==0)
					alert("No path found.");
				else
				{
					server_query.open("POST", "shortest_path.jsp", false);
					server_query.setRequestHeader("Content-type","application/x-www-form-urlencoded");
					server_query.send("node="+vertices.length+"&edges="+edge+"&weights="+weights+"&start="+first+"&end="+last);
					var server_reply = server_query.responseText;
					if(server_reply=="failed!")		// if path not found.
						alert("No path found.");
					else
					{
						server_reply = server_reply.split(",");
						edge_array = [];

						// parsing the received string to form two dimensional arrays of edges forming the spanning tree.
						for(i=0; i<server_reply.length-1; i++)
						{
							temp_edge = [];
							temp_edge.push(parseInt(server_reply[i]));
							temp_edge.push(parseInt(server_reply[i+1]));
							edge_array.push(temp_edge);
						}
						serverRedraw(edge_array);
					}
				}
			}
		}

		// This function is called for calculating the shortest path between two nodes.
		function shortestPath(event)
		{
			if(last_clicked==6)
			{
				point = clickedPoint(event);
				i = isVertex(point);
				if(i<vertices.length)
				{
					sendData(last_selected, i);
				}
				else
					alert("End point not selected. Please select the start and end points again.");

				last_clicked = 1;
			}
			else
			{
				point = clickedPoint(event);
				i = isVertex(point);
				if(i<vertices.length)
				{
					drawCircle(vertices[i].x, vertices[i].y, "#FF00FF");
					last_selected = i;
					last_clicked = 6;
				}
			}
		}

		// This function is called for calculating the minimum spannig tree.
		function minimumSpanningTree()
		{
			if(edges.length>0)
				sendData(-1, -1);
			else if(vertices.length==0)
				alert("Graph is empty, cant compute the minimum spanning tree.");
			else
				alert("Graph has no edges, cant compute the minimum spanning tree.");
		}

		// This function handles the click event for various modes.
		function clickEvent(event)
		{
			if(document.getElementById('add_vertex').checked)
				drawVertex(event);

			else if(document.getElementById('add_edge').checked)
				drawEdge(event);

			else if(document.getElementById('move_vertex').checked)
				moveVertex(event);

			else if(document.getElementById('delete_vertex').checked)
				deleteVertex(event);

			else if(document.getElementById('delete_edge').checked)
				deleteEdge(event);

			else if(document.getElementById('path').checked)
				shortestPath(event);
		}

		// This function moves the selected vertex.
		function moveEvent(event)
		{
			if(last_clicked==3)
			{
				point = clickedPoint(event);
				ctr = 0;

				// if the vertex is moving out of the canvas
				if((point.x<vertex_radius) || (600-point.x<vertex_radius) || (point.y<vertex_radius) || (600-point.y<vertex_radius))
					ctr = 1;

				// if the vertex overlaps during movement.
				if(ctr==0)
				{
					for(i=0; i<vertices.length; i++)
					{
						if(i!=last_selected)
						{
							distance = Math.sqrt((vertices[i].x-point.x)*(vertices[i].x-point.x) + (vertices[i].y-point.y)*(vertices[i].y-point.y));

							if(distance<2*vertex_radius)
							{
								ctr = 1;
								break;
							}

						}
					}
				}

				if(ctr==0)
				{
					vertices[last_selected].x = point.x;
					vertices[last_selected].y = point.y;

				}

				canvasRedraw();
				drawCircle(vertice[last_selected].x, vertices[last_selected].y, "FF00FF");
			}

		}

		// This function handles the mouseup event during moving a vertex.
		function upEvent(event)
		{
			if(last_clicked==3)
			{
				for(j=0; j<edges.length; j++)
				{
					if(edges[j].start==last_selected)
					{
						edges[j].startx = vertices[last_selected].x;
						edges[j].starty = vertices[last_selected].y;
					}

					if(edges[j].end==last_selected)
					{
						edges[j].endx = vertices[last_selected].x;
						edges[j].endy = vertices[last_selected].y;
					}
				}
				last_clicked = 1;
			}
		}

		// Adding the event listeners to the canvas.
		graph_canvas.addEventListener('mousedown',clickEvent, false);
		graph_canvas.addEventListener('mousemove',moveEvent, false);
		graph_canvas.addEventListener('mouseup', upEvent, false);

		// saving the current graph.
		function saveGraph()
		{
			if(document.getElementById("save_bar").value!="")
			{
				// formatting data to be sent.
				var save_vertices = "";
				var save_edges = "";

				for(i=0; i<vertices.length; i++)
					save_vertices += vertices[i].x + ":" + vertices[i].y + ",";

				for(i=0; i<edges.length; i++)
					save_edges += edges[i].start + ":" + edges[i].end + ",";

				// obtaing the file name.
				var file_name = document.getElementById("save_bar").value;

				// sending the data to the server.
				var server_request = new XMLHttpRequest();
				server_request.open("POST", "save_graph.jsp", false);
				server_request.setRequestHeader("Content-type","application/x-www-form-urlencoded");
				server_request.send("filename="+file_name+"&vertices="+save_vertices+"&edges="+save_edges);
				var server_reply = server_request.responseText;

				if(server_reply!="failed\n")
				{
					// alerting and refreshing the dropdown.
					alert("Graph Saved Successfully!");
					populateDropDown();
				}
				else
					alert("Error! Could not save graph...");
			}
		}

		function loadGraph()
		{
			// obtaing the selected file name.
			var index = document.getElementById("files").selectedIndex;
			var file_name = document.getElementById("files").options[index].text;

			// sending the request to the server.
			var server_request = new XMLHttpRequest();
			server_request.open("POST", "load_graph.jsp", false);
			server_request.setRequestHeader("Content-type","application/x-www-form-urlencoded");
			server_request.send("file_name="+file_name);
			var server_reply = server_request.responseText;

			// processing the response.
			if(server_reply=="Failed")
				alert("Error! File not found...");
			else
			{
				server_reply = server_reply.split("$");
				saved_vertices = server_reply[0].split(",");
				saved_edges = server_reply[1].split(",");

				vertices = [];
				edges = []

				// parsing the string to double dimensional arrays of edes and vertices.
				var temp_vertices, temp_edge;
				for(i=0; i<saved_vertices.length-1; i++)
				{
					temp_vertices = saved_vertices[i].split(":");
					point = new Object();
					point.x = parseInt(temp_vertices[0]);
					point.y = parseInt(temp_vertices[1]);
					vertices.push(point);
				}

				for(i=0; i<saved_edges.length-1; i++)
				{
					temp_edge = saved_edges[i].split(":");
					edge = new Object();
					edge.start = parseInt(temp_edge[0]);
					edge.end = parseInt(temp_edge[1]);
					edges.push(edge);
				}
				canvasRedraw();
			}

		}

	// refreshing the drop-down list.
	function populateDropDown()
	{
		document.getElementById("save_bar").value = "";

		// sending request to the server.
		var server_request = new XMLHttpRequest();
		server_request.open("POST", "update_list.jsp", false);
		server_request.setRequestHeader("Content-type","application/x-www-form-urlencoded");
		server_request.send("files");

		// receiving the filenames.
		var server_reply = server_request.responseText;
		server_reply = server_reply.split(",");

		// populating the drop-down.
		var dropDown = "";
		for(i=0; i<server_reply.length; i++)
			dropDown += "<option>"+server_reply[i]+"</option>";
		document.getElementById("files").innerHTML = dropDown;
	}

	// This function clears the canvas.
	function clearGraph()
	{
		vertices = [];
		edges = [];
		canvasRedraw();
	}

	window.onload = populateDropDown();

	</script>
</body>

</html>