This example use HTML5 Canvas to draw a simple graph.
The Node can be dragged to new positions on the canvas.
Last active
April 28, 2020 16:53
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Draggable Graph Nodes
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <script | |
| class="jsbin" | |
| src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script> | |
| <meta | |
| charset=utf-8 | |
| /> | |
| <title>Drag | |
| a | |
| Node</title> | |
| <!--[if IE]> | |
| <script src="http://html5shiv.googlecode.com/svn/trunk/html5.js"></script> | |
| <![endif]--> | |
| <style> | |
| article, aside, figure, footer, header, hgroup, menu, nav, section { | |
| display: block; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <canvas | |
| id="viewer" | |
| width="800" | |
| height="500"></canvas> | |
| <script | |
| src="graph-bfs.js"></script> | |
| </body> | |
| <script> | |
| var graph = { | |
| vertices: [{ | |
| edges: [1, 4], | |
| x: 25, | |
| y: 25 | |
| }, { | |
| edges: [0, 2, 3, 4], | |
| x: 75, | |
| y: 25 | |
| }, { | |
| edges: [1, 3], | |
| x: 125, | |
| y: 75 | |
| }, { | |
| edges: [1, 2, 4], | |
| x: 75, | |
| y: 125 | |
| }, { | |
| edges: [0, 1, 3], | |
| x: 25, | |
| y: 125 | |
| }] | |
| }; | |
| graph.edgelist = (function (G) { | |
| var i, j, edges = [], | |
| e; | |
| var contains = function (a, e) { | |
| var i; | |
| for (i = 0; i < a.length; i += 1) { | |
| if (a[i].n === e.n && a[i].m === e.m) { | |
| return true; | |
| } | |
| if (a[i].m === e.n && a[i].n === e.m) { | |
| return true; | |
| } | |
| } | |
| return false; | |
| }; | |
| for (i = 0; i < G.vertices.length; i += 1) { | |
| for (j = 0; j < G.vertices[i].edges.length; j += 1) { | |
| e = { | |
| n: i, | |
| m: G.vertices[i].edges[j] | |
| }; | |
| if (!contains(edges, { | |
| n: i, | |
| m: G.vertices[i].edges[j] | |
| })) { | |
| edges.push(e); | |
| } | |
| } | |
| } | |
| return edges; | |
| })(graph); | |
| graph.draw = function (ctx) { | |
| var i; | |
| var n, m; | |
| for (i = 0; i < this.edgelist.length; i += 1) { | |
| n = this.vertices[this.edgelist[i].n]; | |
| m = this.vertices[this.edgelist[i].m]; | |
| drawEdge(ctx, n.x, n.y, m.x, m.y); | |
| } | |
| for (i = 0; i < this.vertices.length; i += 1) { | |
| n = this.vertices[i]; | |
| drawNode(ctx, n.x, n.y, n.isGrabbed ? 'black' : 'white'); | |
| } | |
| }; | |
| var drawNode = function (ctx, x, y, color) { | |
| ctx.fillStyle = color; | |
| ctx.beginPath(); | |
| ctx.arc(x, y, 10, 0, Math.PI * 2, true); | |
| ctx.fill(); | |
| ctx.stroke(); | |
| }; | |
| var drawEdge = function (ctx, x0, y0, x1, y1) { | |
| ctx.beginPath(); | |
| ctx.moveTo(x0, y0); | |
| ctx.lineTo(x1, y1); | |
| ctx.stroke(); | |
| }; | |
| graph.getTarget = function (x, y) { | |
| var i; | |
| for (i = 0; i < this.vertices.length; i += 1) { | |
| if (contains(this.vertices[i], x, y)) { | |
| return this.vertices[i]; | |
| } | |
| } | |
| return undefined; | |
| }; | |
| var contains = function (vertex, x, y) { | |
| var dx, dy; | |
| dx = x - vertex.x; | |
| dy = y - vertex.y; | |
| return (Math.sqrt(dx * dx + dy * dy) < 10); | |
| }; | |
| var x_grabOffset, y_grabOffset; | |
| $('#viewer').mousedown(function () { | |
| var offset, x, y, circle, target, search, ctx; | |
| offset = $(this).offset(); | |
| x = event.pageX - offset.left; | |
| y = event.pageY - offset.top; | |
| target = graph.getTarget(x, y); | |
| if (target !== undefined) { | |
| target.isGrabbed = true; | |
| } | |
| x_grabOffset = target.x - x; | |
| y_grabOffset = target.y - y; | |
| ctx = $('#viewer')[0].getContext("2d"); | |
| ctx.clearRect(0, 0, 800, 500); | |
| graph.draw(ctx); | |
| }).mouseup(function () { | |
| var i; | |
| for (i = 0; i < graph.vertices.length; i += 1) { | |
| graph.vertices[i].isGrabbed = false; | |
| } | |
| ctx = $('#viewer')[0].getContext("2d"); | |
| ctx.clearRect(0, 0, 800, 500); | |
| graph.draw(ctx); | |
| }).mousemove(function () { | |
| var i, v, grabbed, offset, x, y; | |
| for (i = 0; i < graph.vertices.length; i += 1) { | |
| v = graph.vertices[i]; | |
| if (v.isGrabbed && v.isGrabbed === true) { | |
| grabbed = v; | |
| } | |
| if (grabbed !== undefined) { | |
| offset = $(this).offset(); | |
| x = event.pageX - offset.left; | |
| y = event.pageY - offset.top; | |
| grabbed.x = x - x_grabOffset; | |
| grabbed.y = y - y_grabOffset; | |
| } | |
| ctx = $('#viewer')[0].getContext("2d"); | |
| ctx.clearRect(0, 0, 800, 500); | |
| graph.draw(ctx); | |
| } | |
| }); | |
| (function () { | |
| var canvas = document.getElementById("viewer"); | |
| if (canvas.getContext) { | |
| var ctx = canvas.getContext("2d"); | |
| graph.draw(ctx); | |
| } | |
| })(); | |
| </script> | |
| </html> |
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how to make it work in mobile?
I'm using it in phonegap application. Above code works great in chrome but not in firefox or mobile device.
Is there any alteration to be made in the code to make it work in all platforms?