Make temporary wheel measurement vars per-instance

Author: Narciso Jaramillo

lib/codemirror.js

@@ -1637,7 +1637,7 @@ window.CodeMirror = (function() {
   // is that it gives us a chance to update the display before the
   // actual scrolling happens, reducing flickering.
 
-  var wheelSamples = 0, wheelDX, wheelDY, wheelStartX, wheelStartY, wheelPixelsPerUnit = null;
+  var wheelSamples = 0, wheelPixelsPerUnit = null;
   // Fill in a browser-detected starting value on browsers where we
   // know one. These don't have to be accurate -- the result of them
   // being wrong would just be a slight flicker on the first wheel
@@ -1678,7 +1678,7 @@ window.CodeMirror = (function() {
         setScrollTop(cm, Math.max(0, Math.min(scroll.scrollTop + dy * wheelPixelsPerUnit, scroll.scrollHeight - scroll.clientHeight)));
       setScrollLeft(cm, Math.max(0, Math.min(scroll.scrollLeft + dx * wheelPixelsPerUnit, scroll.scrollWidth - scroll.clientWidth)));
       e_preventDefault(e);
-      wheelStartX = null; // Abort measurement, if in progress
+      cm.wheelStartX = null; // Abort measurement, if in progress
       return;
     }
 
@@ -1691,22 +1691,22 @@ window.CodeMirror = (function() {
     }
 
     if (wheelSamples < 20) {
-      if (wheelStartX == null) {
-        wheelStartX = scroll.scrollLeft; wheelStartY = scroll.scrollTop;
-        wheelDX = dx; wheelDY = dy;
+      if (cm.wheelStartX == null) {
+        cm.wheelStartX = scroll.scrollLeft; cm.wheelStartY = scroll.scrollTop;
+        cm.wheelDX = dx; cm.wheelDY = dy;
         setTimeout(function() {
-          if (wheelStartX == null) return;
-          var movedX = scroll.scrollLeft - wheelStartX;
-          var movedY = scroll.scrollTop - wheelStartY;
-          var sample = (movedY && wheelDY && movedY / wheelDY) ||
-            (movedX && wheelDX && movedX / wheelDX);
-          wheelStartX = wheelStartY = null;
+          if (cm.wheelStartX == null) return;
+          var movedX = scroll.scrollLeft - cm.wheelStartX;
+          var movedY = scroll.scrollTop - cm.wheelStartY;
+          var sample = (movedY && cm.wheelDY && movedY / cm.wheelDY) ||
+            (movedX && cm.wheelDX && movedX / cm.wheelDX);
+          cm.wheelStartX = cm.wheelStartY = null;
           if (!sample) return;
           wheelPixelsPerUnit = (wheelPixelsPerUnit * wheelSamples + sample) / (wheelSamples + 1);
           ++wheelSamples;
         }, 200);
       } else {
-        wheelDX += dx; wheelDY += dy;
+        cm.wheelDX += dx; cm.wheelDY += dy;
       }
     }
   }