code: public void increaseFontSize() {
          // move INTO range if we have just moved OUT of lower virtual
          if (inRange() || (atMin() && atLowerBoundary())) {
              currentFontIndex++;
          } else if (atMax()) {
              upperVirtualCount++;
          } else if (atMin() && inLower()) {
              lowerVirtualCount++;
          }
      }
docs: Move the font size pointer up. If this would move the pointer past
  the maximum font size, track this increase with a virtual size.