New cpp folder structure

Signed-off-by: Alexander Borsuk <me@alex.bio>

libs/drape_frontend/gui/ruler_helper.hpp

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+
+class ScreenBase;
+
+namespace gui
+{
+class RulerHelper
+{
+public:
+  RulerHelper();
+
+  void Update(ScreenBase const & screen);
+  static bool IsVisible(ScreenBase const & screen);
+  void Invalidate();
+
+  static float GetRulerHalfHeight();
+  float GetRulerPixelLength() const;
+  static float GetMaxRulerPixelLength();
+  static int GetVerticalTextOffset();
+  bool IsTextDirty() const;
+  std::string const & GetRulerText() const;
+  void ResetTextDirtyFlag();
+  static void GetTextInitInfo(std::string & alphabet, uint32_t & size);
+
+private:
+  double CalcMetersDiff(double value);
+  void SetTextDirty();
+
+private:
+  float m_pixelLength;
+  int m_rangeIndex;
+  std::string m_rulerText;
+  bool m_isTextDirty;
+  mutable bool m_dirtyTextRequested;
+  int m_currentDrawScale = 0;
+};
+}  // namespace gui