Add some comments about some previous modifications (#6533)

public/app/plugins/panel/graph/graph.ts

@@ -183,6 +183,8 @@ module.directive('grafanaGraph', function($rootScope, timeSrv) {
         }
       }
 
+      // Series could have different timeSteps,
+      // let's find the smallest one so that bars are correctly rendered.
       function getMinTimeStepOfSeries(data) {
         var min = 100000000000;
 

public/app/plugins/panel/graph/graph_tooltip.js

@@ -21,7 +21,9 @@ function ($) {
       var initial = last*ps;
       var len = series.datapoints.points.length;
       for (var j = initial; j < len; j += ps) {
+        // Special case of a non stepped line, highlight the very last point just before a null point
         if ((series.datapoints.points[initial] != null && series.datapoints.points[j] == null && ! series.lines.steps)
+            //normal case
             || series.datapoints.points[j] > posX) {
           return Math.max(j - ps,  0)/ps;
         }
@@ -58,11 +60,13 @@ function ($) {
         series = seriesList[i];
 
         if (!series.data.length || (panel.legend.hideEmpty && series.allIsNull)) {
+          // Init value & yaxis so that it does not brake series sorting
           results.push({ hidden: true, value: 0, yaxis: 0 });
           continue;
         }
 
         if (!series.data.length || (panel.legend.hideZero && series.allIsZero)) {
+          // Init value & yaxis so that it does not brake series sorting
           results.push({ hidden: true, value: 0, yaxis: 0 });
           continue;
         }
@@ -71,6 +75,7 @@ function ($) {
         hoverDistance = pos.x - series.data[hoverIndex][0];
         pointTime = series.data[hoverIndex][0];
 
+        // Take the closest point before the cursor, or if it does not exist, the closest after
         if (! minDistance
             || (hoverDistance >=0 && (hoverDistance < minDistance || minDistance < 0))
             || (hoverDistance < 0 && hoverDistance > minDistance)) {
@@ -99,6 +104,7 @@ function ($) {
           hoverIndex = this.findHoverIndexFromDataPoints(pos.x, series, hoverIndex);
         }
 
+        // Be sure we have a yaxis so that it does not brake series sorting
         yaxis = 0;
         if (series.yaxis) {
           yaxis = series.yaxis.n;
@@ -116,7 +122,7 @@ function ($) {
         });
       }
 
-      // Find point which closer to pointer
+      // Time of the point closer to pointer
       results.time = minTime;
 
       return results;

public/vendor/flot/jquery.flot.js

@@ -1210,7 +1210,7 @@ Licensed under the MIT license.
                         // middle point has same y
                         points[k + 1] = points[k - ps + 1] || 0;
 
-                        // if series has null values, let's give the last correct value a nice step
+                        // if series has null values, let's give the last !null value a nice step
                         if(nullify)
                         	points[k] = p[0];
 

public/vendor/flot/jquery.flot.stack.js

@@ -78,9 +78,12 @@ charts or filled areas).
                 i = 0, j = 0, l, m;
 
             while (true) {
+                // browse all points from the current series and from the previous series
                 if (i >= points.length && j >= otherpoints.length)
                     break;
 
+                // newpoints will replace current series with
+                // as many points as different timestamps we have in the 2 (current & previous) series
                 l = newpoints.length;
                 px = points[i + keyOffset];
                 py = points[i + accumulateOffset];
@@ -89,30 +92,32 @@ charts or filled areas).
                 bottom = 0;
 
                 if (i < points.length && px == null) {
-                    // ignore point
+                    // let's ignore null points from current series, nothing to do with them
                     i += ps;
                 }
                 else if (j < otherpoints.length && qx == null) {
-                    // ignore point
+                    // let's ignore null points from previous series, nothing to do with them
                     j += otherps;
                 }
                 else if (i >= points.length) {
-                    // take the remaining points from the previous series
+                    // no more points in the current series, simply take the remaining points
+                    // from the previous series so that next series will correctly stack
                     for (m = 0; m < ps; ++m)
                         newpoints.push(otherpoints[j + m]);
                     bottom = qy;
                     j += otherps;
                 }
                 else if (j >= otherpoints.length) {
-                    // take the remaining points from the current series
+                    // no more points in the previous series, of course let's take
+                    // the remaining points from the current series
                     for (m = 0; m < ps; ++m)
                         newpoints.push(points[i + m]);
                     i += ps;
                 }
                 else {
-                    // cases where we actually got two points
+                    // next available points from current and previous series have the same timestamp
                     if (px == qx) {
-                        // take the point from the current series and skip the previous' one
+                        // so take the point from the current series and skip the previous' one
                         for (m = 0; m < ps; ++m)
                             newpoints.push(points[i + m]);
 
@@ -122,8 +127,9 @@ charts or filled areas).
                         i += ps;
                         j += otherps;
                     }
+                    // next available point with the smallest timestamp is from the previous series
                     else if (px > qx) {
-                        // take the point from the previous series so that the next series can stack over it
+                        // so take the point from the previous series so that next series will correctly stack
                         for (m = 0; m < ps; ++m)
                             newpoints.push(otherpoints[j + m]);
 
@@ -135,8 +141,9 @@ charts or filled areas).
 
                         j += otherps;
                     }
-                    else { // px < qx
-                        // take the point from the current series
+                    // (px < qx) next available point with the smallest timestamp is from the current series
+                    else {
+                        // so of course let's take the point from the current series
                         for (m = 0; m < ps; ++m)
                             newpoints.push(points[i + m]);