From cc88109271b14143ae6abe20948bdb731b09b5ba Mon Sep 17 00:00:00 2001
From: Nils Schneider <nils@nilsschneider.net>
Date: Fri, 10 Apr 2015 20:47:11 +0200
Subject: [PATCH] forcegraph: convert to canvas

---
 lib/forcegraph.js     | 295 ++++++++++++++++++++++++++----------------
 scss/_forcegraph.scss |  56 ++------
 2 files changed, 194 insertions(+), 157 deletions(-)

diff --git a/lib/forcegraph.js b/lib/forcegraph.js
index 92bd467..4a35ae5 100644
--- a/lib/forcegraph.js
+++ b/lib/forcegraph.js
@@ -1,7 +1,8 @@
 define(["d3"], function (d3) {
    return function (config, linkScale, sidebar, router) {
     var self = this
-    var svg, vis, link, node, label
+    var svg, canvas, ctx
+    var svgNodes, svgLinks
     var nodesDict, linksDict
     var zoomBehavior
     var force
@@ -10,6 +11,8 @@ define(["d3"], function (d3) {
     var intNodes = []
     var intLinks = []
     var highlight
+    var highlightedNodes = []
+    var highlightedLinks = []
 
     var LINK_DISTANCE = 70
 
@@ -57,23 +60,48 @@ define(["d3"], function (d3) {
                           .on("dragend", dragend)
 
     function animatePanzoom(translate, scale) {
-      zoomBehavior.scale(scale)
-      zoomBehavior.translate(translate)
+      var translateP = zoomBehavior.translate()
+      var scaleP = zoomBehavior.scale()
 
-      var el = vis
+      if (!doAnimation) {
+        zoomBehavior.translate(translate)
+        zoomBehavior.scale(scale)
+        panzoom()
+      } else {
+        var start = {x: translateP[0], y: translateP[1], scale: scaleP}
+        var end = {x: translate[0], y: translate[1], scale: scale}
 
-      if (doAnimation)
-        el = el.transition().duration(500)
+        var interpolate = d3.interpolateObject(start, end)
+        var duration = 500
 
-      el.attr("transform", "translate(" + translate + ") " +
-                           "scale(" + scale + ")")
+        var ease = d3.ease("cubic-in-out")
+
+        d3.timer(function (t) {
+          if (t >= duration)
+            return true
+
+          var v = interpolate(ease(t / duration))
+          zoomBehavior.translate([v.x, v.y])
+          zoomBehavior.scale(v.scale)
+          panzoom()
+
+          return false
+        })
+      }
     }
 
     function panzoom() {
       var translate = zoomBehavior.translate()
       var scale = zoomBehavior.scale()
-      vis.attr("transform", "translate(" + translate + ") " +
+
+      panzoomReal(translate, scale)
+    }
+
+    function panzoomReal(translate, scale) {
+      svg.attr("transform", "translate(" + translate + ") " +
                             "scale(" + scale + ")")
+
+      redraw()
     }
 
     function getSize() {
@@ -105,15 +133,15 @@ define(["d3"], function (d3) {
     }
 
     function updateHighlight(nopanzoom) {
+      highlightedNodes = []
+      highlightedLinks = []
+
       if (highlight !== undefined)
         if (highlight.type === "node") {
           var n = nodesDict[highlight.o.nodeinfo.node_id]
 
           if (n) {
-            link.classed("highlight", false)
-            node.classed("highlight", function (e) {
-              return e.o.node === n.o.node && n.o.node !== undefined
-            })
+            highlightedNodes = [n]
 
             if (!nopanzoom)
               panzoomTo([n.x, n.y], [n.x, n.y])
@@ -124,10 +152,7 @@ define(["d3"], function (d3) {
           var l = linksDict[highlight.o.id]
 
           if (l) {
-            node.classed("highlight", false)
-            link.classed("highlight", function (e) {
-              return e.o === l.o && l.o !== undefined
-            })
+            highlightedLinks = [l]
 
             if (!nopanzoom) {
               var x = d3.extent([l.source, l.target], function (d) { return d.x })
@@ -139,129 +164,167 @@ define(["d3"], function (d3) {
           return
         }
 
-      node.classed("highlight", false)
-      link.classed("highlight", false)
-
       if (!nopanzoom)
         panzoomTo([0, 0], force.size())
     }
 
     function updateLinks(vis, data) {
-      var link = vis.selectAll("g.link")
-                .data(data, function (d) { return d.o.id })
+      var link = vis.selectAll("line")
+                    .data(data, function (d) { return d.o.id })
 
       link.exit().remove()
 
-      var linkEnter = link.enter().append("g")
-                          .attr("class", "link")
-                          .on("click", function (d) {
-                            if (!d3.event.defaultPrevented)
-                              router.link(d.o)()
-                          })
-
-      linkEnter.append("line")
-               .append("title")
-
-      link.selectAll("line")
-          .style("stroke", function (d) { return linkScale(d.o.tq).hex() })
-
-      link.selectAll("title").text(function (d) { return showTq(d.o) })
+      link.enter().append("line")
+                  .on("click", function (d) {
+                    if (!d3.event.defaultPrevented)
+                      router.link(d.o)()
+                  })
 
       return link
     }
 
     function updateNodes(vis, data) {
-      var node = vis.selectAll(".node")
+      var node = vis.selectAll("circle")
                     .data(data, function(d) { return d.o.id })
 
       node.exit().remove()
 
       node.enter().append("circle")
-          .attr("r", 8)
+          .attr("r", 12)
           .on("click", function (d) {
             if (!d3.event.defaultPrevented)
               router.node(d.o.node)()
           })
           .call(draggableNode)
 
-      node.attr("class", function (d) {
-        var s = ["node"]
-        if (!d.o.node)
-          s.push("unknown")
-
-        return s.join(" ")
-      })
-
       return node
     }
 
-    function updateLabels(vis, data) {
-      var label = vis.selectAll("text")
-                     .data(data, function(d) { return d.o.id })
+    function drawLabel(d) {
+      var sum = d.neighbours.reduce(function (a, b) {
+        return [a[0] + b.x, a[1] + b.y]
+      }, [0, 0])
 
-      label.exit().remove()
+      var sumCos = sum[0] - d.x * d.neighbours.length
+      var sumSin = sum[1] - d.y * d.neighbours.length
 
-      var labelEnter = label.enter().append("text")
+      var angle = Math.PI / 2
 
-      label.text(nodeName)
-           .each(function (d) {
-             var bbox = this.getBBox()
-             d.labelHeight = bbox.height
-             d.labelWidth = bbox.width
-           })
+      if (d.neighbours.length > 0)
+        angle = Math.PI + Math.atan2(sumSin, sumCos)
 
-      labelEnter.each(function (d) {
-        d.labelAngle = Math.PI / 2
-      })
+      var cos = Math.cos(angle)
+      var sin = Math.sin(angle)
 
-      return label
+      var x = d.x + d.labelA * Math.pow(Math.abs(cos), 2 / 5) * Math.sign(cos)
+      var y = d.y + d.labelB * Math.pow(Math.abs(sin), 2 / 5) * Math.sign(sin)
+
+      ctx.fillText(d.label, x, y)
     }
 
-    function positionLabels() {
-      label.attr("transform", function(d) {
-        var neighbours = d.neighbours.map(function (n) {
-          var dx = n.x - d.x
-          var dy = n.y - d.y
+    function redraw() {
+      var translate = zoomBehavior.translate()
+      var scale = zoomBehavior.scale()
+      var nodes = intNodes.filter(function (d) { return d.o.node })
+      var unknownNodes = intNodes.filter(function (d) { return !d.o.node })
+      var links = intLinks
+      ctx.save()
+      ctx.font = "11px Roboto"
+      ctx.clearRect(0, 0, canvas.width, canvas.height)
+      ctx.translate(translate[0], translate[1])
+      ctx.scale(scale, scale)
 
-          return (2 * Math.PI + Math.atan2(dy, dx)) % (2 * Math.PI)
+      if (highlightedLinks.length) {
+        ctx.save()
+        ctx.lineWidth = 16
+        ctx.strokeStyle = "#FFD486"
+
+        highlightedLinks.forEach(function (d) {
+          ctx.beginPath()
+          ctx.moveTo(d.source.x, d.source.y)
+          ctx.lineTo(d.target.x, d.target.y)
+          ctx.stroke()
         })
 
-        var sumCos = neighbours.reduce(function (a, b) {
-          return a + Math.cos(b)
-        }, 0)
+        ctx.restore()
+      }
 
-        var sumSin = neighbours.reduce(function (a, b) {
-          return a + Math.sin(b)
-        }, 0)
+      ctx.lineWidth = 2.5
 
-        if (neighbours.length > 0)
-          d.labelAngle = Math.PI + Math.atan2(sumSin, sumCos)
-
-        var offset = 10
-
-        var a = offset + d.labelWidth / 2
-        var b = offset + d.labelHeight / 2
-
-        var cos = Math.cos(d.labelAngle)
-        var sin = Math.sin(d.labelAngle)
-
-        var x = d.x + a * Math.pow(Math.abs(cos), 2 / 5) * Math.sign(cos)
-        var y = d.y + b * Math.pow(Math.abs(sin), 2 / 5) * Math.sign(sin)
-
-        return "translate(" + x + "," + y + ")"
+      links.forEach(function (d) {
+        ctx.beginPath()
+        ctx.moveTo(d.source.x, d.source.y)
+        ctx.lineTo(d.target.x, d.target.y)
+        ctx.strokeStyle = d.color
+        ctx.stroke()
       })
+
+      ctx.textAlign = "center"
+      ctx.textBaseline = "middle"
+      ctx.fillStyle = "rgba(0, 0, 0, 0.6)"
+
+      intNodes.forEach(drawLabel)
+
+      ctx.beginPath()
+      unknownNodes.forEach(function (d) {
+        ctx.moveTo(d.x + 8, d.y)
+        ctx.arc(d.x, d.y, 8, 0, 2 * Math.PI)
+      })
+
+      ctx.strokeStyle = "#d00000"
+      ctx.fillStyle = "#ffffff"
+
+      ctx.fill()
+      ctx.stroke()
+
+      ctx.beginPath()
+      nodes.forEach(function (d) {
+        ctx.moveTo(d.x + 8, d.y)
+        ctx.arc(d.x, d.y, 8, 0, 2 * Math.PI)
+      })
+
+      ctx.strokeStyle = "#AEC7E8"
+      ctx.fillStyle = "#ffffff"
+
+      ctx.fill()
+      ctx.stroke()
+
+      if (highlightedNodes.length) {
+        ctx.save()
+        ctx.strokeStyle = "#FFD486"
+        ctx.fillStyle = "orange"
+        ctx.lineWidth = 6
+
+        highlightedNodes.forEach(function (d) {
+          ctx.beginPath()
+          ctx.moveTo(d.x + 8, d.y)
+          ctx.arc(d.x, d.y, 8, 0, 2 * Math.PI)
+          ctx.fill()
+          ctx.stroke()
+        })
+
+        ctx.restore()
+      }
+
+      ctx.restore()
     }
 
     function tickEvent() {
-      link.selectAll("line")
-          .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 })
+      redraw()
 
-      node.attr("cx", function (d) { return d.x })
-                         .attr("cy", function (d) { return d.y })
-      positionLabels()
+      svgLinks.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 })
+
+      svgNodes.attr("cx", function (d) { return d.x })
+              .attr("cy", function (d) { return d.y })
+    }
+
+    function resizeCanvas() {
+      canvas.width = el.offsetWidth
+      canvas.height = el.offsetHeight
+      redraw()
     }
 
     el = document.createElement("div")
@@ -273,15 +336,17 @@ define(["d3"], function (d3) {
                      .on("zoom", panzoom)
                      .translate([sidebar.getWidth(), 0])
 
+    canvas = d3.select(el).append("canvas").node()
+
     svg = d3.select(el).append("svg")
             .attr("pointer-events", "all")
             .call(zoomBehavior)
+            .append("g")
 
-    vis = svg.append("g")
+    var visLinks = svg.append("g")
+    var visNodes = svg.append("g")
 
-    var visLinks = vis.append("g").attr("class", "links")
-    var visLabels = vis.append("g").attr("class", "labels")
-    var visNodes = vis.append("g").attr("class", "nodes")
+    ctx = canvas.getContext("2d")
 
     force = d3.layout.force()
               .charge(-80)
@@ -294,6 +359,8 @@ define(["d3"], function (d3) {
               .on("tick", tickEvent)
               .on("end", savePositions)
 
+    window.addEventListener("resize", resizeCanvas)
+
     panzoom()
 
     self.setData = function (data) {
@@ -339,6 +406,7 @@ define(["d3"], function (d3) {
         e.o = d
         e.source = newNodesDict[d.source.id]
         e.target = newNodesDict[d.target.id]
+        e.color = linkScale(d.tq).hex()
 
         return e
       })
@@ -351,6 +419,15 @@ define(["d3"], function (d3) {
 
         if (d.o.node)
           nodesDict[d.o.node.nodeinfo.node_id] = d
+
+        d.label = nodeName(d)
+
+        ctx.font = "11px Roboto"
+        var offset = 10
+        var width = ctx.measureText(d.label).width
+
+        d.labelA = offset + width / 2
+        d.labelB = offset + 11 / 2
       })
 
       intLinks.forEach(function (d) {
@@ -367,9 +444,8 @@ define(["d3"], function (d3) {
         })
       })
 
-      link = updateLinks(visLinks, intLinks)
-      node = updateNodes(visNodes, intNodes)
-      label = updateLabels(visLabels, intNodes)
+      svgLinks = updateLinks(visLinks, intLinks)
+      svgNodes = updateNodes(visNodes, intNodes)
 
       if (localStorageTest()) {
         var save = JSON.parse(localStorage.getItem("graph/nodeposition"))
@@ -380,7 +456,7 @@ define(["d3"], function (d3) {
             nodePositions[d.id] = d
           })
 
-          node.each( function (d) {
+          intNodes.forEach( function (d) {
             if (nodePositions[d.o.id] && (d.x === undefined || d.y === undefined)) {
               d.x = nodePositions[d.o.id].x
               d.y = nodePositions[d.o.id].y
@@ -397,8 +473,8 @@ define(["d3"], function (d3) {
 
       updateHighlight(true)
 
-      if (node.enter().size() + link.enter().size() > 0)
-        force.start()
+      force.start()
+      resizeCanvas()
     }
 
     self.resetView = function () {
@@ -421,14 +497,9 @@ define(["d3"], function (d3) {
 
     self.destroy = function () {
       force.stop()
-      node.remove()
-      link.remove()
-      svg.remove()
+      canvas.remove()
       force = null
       svg = null
-      vis = null
-      link = null
-      node = null
     }
 
     return self
diff --git a/scss/_forcegraph.scss b/scss/_forcegraph.scss
index 54a6555..719d8ef 100644
--- a/scss/_forcegraph.scss
+++ b/scss/_forcegraph.scss
@@ -3,58 +3,24 @@
   width: 100%;
   background: url(img/gplaypattern.png);
 
-  svg {
+  canvas {
     display: block;
     width: 100%;
     height: 100%;
   }
 
-  .link {
-    stroke-opacity: 0.8;
+  svg {
+    display: block;
+    width: 100%;
+    height: 100%;
+    position: absolute;
+    top: 0;
+    left: 0;
 
-    line {
-      stroke-width: 2.5px;
+    circle, line {
+      opacity: 0;
+      stroke-width: 16px;
       cursor: pointer;
     }
-
-    &.highlight line {
-      stroke-width: 7px;
-      stroke-dasharray: 10, 10;
-      opacity: 1;
-    }
-  }
-
-  .node {
-    fill: #fff;
-    stroke-width: 2.5px;
-    stroke: #AEC7E8;
-    
-    &:not(.unknown) {
-      cursor: pointer;
-    }
-
-    &.highlight {
-      stroke: #FFD486;
-      stroke-width: 6px;
-      fill: orange;
-      point-order: stroke;
-    }
-
-    &.unknown {
-      stroke: #d00000;
-    }
-  }
-
-  .labels {
-    text {
-      font-size: 7pt;
-      font-family: Roboto;
-      alignment-baseline: central;
-      text-anchor: middle;
-      fill: rgba(0, 0, 0, 0.6);
-      paint-order: stroke;
-      stroke-width: 3pt;
-      stroke: rgba(255, 255, 255, 0.5);
-    }
   }
 }