in the beginning

arbor_src/tween/tween.js

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+//
+// tween.js
+//
+// interpolator of .data field members for nodes and edges
+//
+
+  var Tween = function(){
+    var _tweens = {}
+    var _done = true
+    
+    var that = {
+      init:function(){
+        return that
+      },
+      
+      busy:function(){
+        var busy = false
+        for (var k in _tweens){ busy=true; break}
+        return busy
+      },
+      
+      to:function(node, dur, to){
+        var now = new Date().valueOf()
+        var seenFields = {}
+
+        var tween = {from:{}, to:{}, colors:{}, node:node, t0:now, t1:now+dur*1000, dur:dur*1000}
+        var easing_fn = "linear"
+        for (var k in to){
+          if (k=='easing'){
+            // need to do better here. case insensitive and default to linear
+            // also be okay with functions getting passed in
+            var ease = to[k].toLowerCase()
+            if (ease in Easing) easing_fn = ease
+            continue
+          }else if (k=='delay'){
+            var delay = (to[k]||0) * 1000
+            tween.t0 += delay
+            tween.t1 += delay
+            continue
+          }
+          
+          if (Colors.validate(to[k])){
+            // it's a hex color string value
+            tween.colors[k] = [Colors.decode(node.data[k]), Colors.decode(to[k]), to[k]]
+            seenFields[k] = true
+          }else{
+            tween.from[k] = (node.data[k]!=undefined) ? node.data[k] : to[k]
+            tween.to[k] = to[k]
+            seenFields[k] = true
+          }
+        }
+        tween.ease = Easing[easing_fn]
+
+        if (_tweens[node._id]===undefined) _tweens[node._id] = []
+        _tweens[node._id].push(tween)
+        
+        // look through queued prunes for any redundancies
+        if (_tweens.length>1){
+          for (var i=_tweens.length-2; i>=0; i++){
+            var tw = _tweens[i]
+
+            for (var k in tw.to){
+              if (k in seenFields) delete tw.to[k]
+              else seenFields[k] = true
+            }
+
+            for (var k in tw.colors){
+              if (k in seenFields) delete tw.colors[k]
+              else seenFields[k] = true
+            }
+
+            if ($.isEmptyObject(tw.colors) && $.isEmptyObject(tw.to)){
+              _tweens.splice(i,1)
+            }
+
+          }
+        }
+        
+        _done = false
+      },
+
+      interpolate:function(pct, src, dst, ease){
+        ease = (ease||"").toLowerCase()
+        var easing_fn = Easing.linear
+        if (ease in Easing) easing_fn = Easing[ease]
+
+        var proportion = easing_fn( pct, 0,1, 1 )
+        if (Colors.validate(src) && Colors.validate(dst)){
+          return lerpRGB(proportion, src,dst)
+        }else if (!isNaN(src)){
+          return lerpNumber(proportion, src,dst)
+        }else if (typeof src=='string'){
+          return (proportion<.5) ? src : dst
+        }
+        
+      },
+
+      tick:function(){
+        var empty = true
+        for (var k in _tweens){ empty=false; break}
+        if (empty) return
+        
+        var now = new Date().valueOf()
+        
+        $.each(_tweens, function(id, tweens){
+          var unprunedTweens = false
+          
+          $.each(tweens, function(i, tween){
+            var proportion = tween.ease( (now-tween.t0), 0,1, tween.dur )
+            proportion = Math.min(1.0, proportion)
+            var from = tween.from
+            var to = tween.to
+            var colors = tween.colors
+            var nodeData = tween.node.data
+
+            var lastTick = (proportion==1.0)
+
+            for (var k in to){
+              switch (typeof to[k]){
+                case "number":
+                  nodeData[k] = lerpNumber(proportion, from[k], to[k])
+                  if (k=='alpha') nodeData[k] = Math.max(0,Math.min(1, nodeData[k]))
+                  break
+                case "string":
+                  if (lastTick){
+                    nodeData[k] = to[k]
+                  }
+                  break
+              }
+            }
+            
+            for (var k in colors){
+              if (lastTick){
+                nodeData[k] = colors[k][2]
+              }else{
+                var rgb = lerpRGB(proportion, colors[k][0], colors[k][1])
+                nodeData[k] = Colors.encode(rgb)
+              }
+            }
+
+            if (lastTick){
+               tween.completed = true
+               unprunedTweens = true
+            }
+          })
+          
+          if (unprunedTweens){
+            _tweens[id] = $.map(tweens, function(t){ if (!t.completed) return t})
+            if (_tweens[id].length==0) delete _tweens[id]
+          }
+        })
+        
+        _done = $.isEmptyObject(_tweens)
+        return _done
+      }
+    }
+    return that.init()
+  }
+  
+  var lerpNumber = function(proportion,from,to){
+    return from + proportion*(to-from)
+  }
+  
+  var lerpRGB = function(proportion,from,to){
+    proportion = Math.max(Math.min(proportion,1),0)
+    var mixture = {}
+    
+    $.each('rgba'.split(""), function(i, c){
+      mixture[c] = Math.round( from[c] + proportion*(to[c]-from[c]) )
+    })
+    return mixture
+  }
+
+  
+// })()