fixed centering heatmap colors

(and other rounding issue with samerange)

libs/css2/selection-panels.css

@@ -40,7 +40,7 @@
     max-height: 30%;
     padding: 0 5px;
     overflow-y:scroll;
-    bottom:0;
+    bottom:18px;
     left:0;
     border:solid 1px black;
     background-color:white;

tinawebJS/enviroment.js

@@ -97,11 +97,23 @@ function getHeatmapColors(nClasses) {
   }
 
   // floor
-  let skipStep = parseInt(listsLen / nHalfToPick)
+  let exactStep = listsLen / nHalfToPick
+  let skipStep = parseInt(exactStep)    // incrmt must be int (used for arr idx)
 
-  // cold colors
+  // to compensate for the fractional part
+  let delta = exactStep - skipStep
+  let drift = 0
+
+  // cold colors, starting from deepest color
   for (let i = listsLen-1 ; i > 0 ; i -= skipStep ) {
     outColors.push(TW.gui.heatmapColorListToColdest[i])
+
+    // catching back one step from time to time
+    drift += delta
+    if (drift >= 1) {
+      i--
+      drift -= 1
+    }
   }
 
   // white

tinawebJS/sigma.parseCustom.js

@@ -410,9 +410,8 @@ function facetsBinning (valuesIdx) {
 
           // same interval each time
           let step = (vMax - vMin) / nBins
-
-          for (var k=vMin ; k < vMax ; k += step ){
-            legendRefTicks.push(k)
+          for (var i = 0 ; i < nBins ; i++) {
+            legendRefTicks.push(vMin + i*step)
           }
           // NB these ticks are *minimums* so we stop one step *before* vMax
           //    and simply include it in last interval