findTopCellItem() handle underflow (f4)

Meter.c

@@ -410,6 +410,8 @@ static uint8_t GraphMeterMode_findTopCellItem(const Meter* this, double scaledTo
       // Find the item that occupies the largest area of the top cell.
       // Favor item with higher index in case of a tie.
 
+      double area = (value / scaledTotal) * (double)(int)graphHeight;
+
       // if (maxValue <= 0.0)
       // if (topCellItem >= i)
       if (topCellItem > i) {
@@ -422,7 +424,6 @@ static uint8_t GraphMeterMode_findTopCellItem(const Meter* this, double scaledTo
          // If (topCell == 0), permit the cases where the division underflows
          // (topPoint == 0.0).
 
-         double area = (value / scaledTotal) * (double)(int)graphHeight;
          if (area > topPoint - (double)(int)topCell) {
             hasArea = true;
 	    maxValue = topPoint - (double)(int)topCell;
@@ -432,7 +433,6 @@ static uint8_t GraphMeterMode_findTopCellItem(const Meter* this, double scaledTo
          topCellItem = i;
       } else {
          if (hasArea) {
-            double area = (value / scaledTotal) * (double)(int)graphHeight;
             if (area >= maxValue) {
                hasArea = false;
                maxValue = value;