Readied 3d camera orientation code for merge into develop branch

lib/graph3d/Graph3d.js

@@ -1888,6 +1888,19 @@ Graph3d.prototype._redrawDataGraph = function() {
 // End methods for drawing points per graph style.
 // -----------------------------------------------------------------------------
 
+/**
+ * Store startX, startY and startOffset for mouse operations
+ *
+ * @param {Event}     event     The event that occurred
+ */
+Graph3d.prototype._storeMousePosition = function(event) {
+  // get mouse position (different code for IE and all other browsers)
+  this.startMouseX = getMouseX(event);
+  this.startMouseY = getMouseY(event);
+  
+  this._startCameraOffset = this.camera.getOffset();
+};
+
 
 /**
  * Start a moving operation inside the provided parent element
@@ -1907,11 +1920,7 @@ Graph3d.prototype._onMouseDown = function(event) {
   this.leftButtonDown = event.which ? (event.which === 1) : (event.button === 1);
   if (!this.leftButtonDown && !this.touchDown) return;
 
-  // get mouse position (different code for IE and all other browsers)
-  this.startMouseX = getMouseX(event);
-  this.startMouseY = getMouseY(event);
-  
-  this._startCameraOffset = this.camera.getOffset();
+  this._storeMousePosition(event);
 
   this.startStart = new Date(this.start);
   this.startEnd = new Date(this.end);
@@ -1938,36 +1947,25 @@ Graph3d.prototype._onMouseDown = function(event) {
  */
 Graph3d.prototype._onMouseMove = function (event) {
   event = event || window.event;
+
+  // calculate change in mouse position
+  var diffX = parseFloat(getMouseX(event)) - this.startMouseX;
+  var diffY = parseFloat(getMouseY(event)) - this.startMouseY;
   
-    // move with ctrl or rotate by other
+  // move with ctrl or rotate by other
   if (event && event.ctrlKey === true) {
       // calculate change in mouse position
-      var camera = this.camera,
-          offset = camera.getOffset();
-	  
-      var diffX = parseFloat(getMouseX(event)) - this.startMouseX;
-      var diffY = parseFloat(getMouseY(event)) - this.startMouseY;
-
-      var scaleX = this.frame.clientWidth * 0.5;
-	  var scaleY = this.frame.clientHeight * 0.5;
+      var scaleX = this.frame.clientWidth  * 0.5;
+      var scaleY = this.frame.clientHeight * 0.5;
 
       var offXNew = (this._startCameraOffset.x || 0) - ((diffX / scaleX) * this.camera.armLength) * 0.8;
       var offYNew = (this._startCameraOffset.y || 0) + ((diffY / scaleY) * this.camera.armLength) * 0.8;
 	  
       this.camera.setOffset(offXNew, offYNew);
-
-	  // меняем startX, startY и startOffset
-	  this._startCameraOffset = this.camera.getOffset();
-	  this.startMouseX = getMouseX(event);
-	  this.startMouseY = getMouseY(event);
+      this._storeMousePosition(event);
     } else {
-
-      // calculate change in mouse position
-      var diffX = parseFloat(getMouseX(event)) - this.startMouseX;
-      var diffY = parseFloat(getMouseY(event)) - this.startMouseY;
-
       var horizontalNew = this.startArmRotation.horizontal + diffX / 200;
-      var verticalNew = this.startArmRotation.vertical + diffY / 200;
+      var verticalNew   = this.startArmRotation.vertical   + diffY / 200;
 
       var snapAngle = 4; // degrees
       var snapValue = Math.sin(snapAngle / 360 * 2 * Math.PI);