From e1bde330986d77b9dd37b792aba94530352b0cf0 Mon Sep 17 00:00:00 2001
From: Daria Volvenkova <d.volvenkova@corp.mail.ru>
Date: Thu, 26 Nov 2015 12:38:32 +0300
Subject: [PATCH] Don't show path text in perspective when it is too small.

---
 drape/overlay_handle.hpp           |  1 +
 drape/overlay_tree.cpp             | 19 +++++++++++++++++--
 drape_frontend/path_text_shape.cpp |  2 ++
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/drape/overlay_handle.hpp b/drape/overlay_handle.hpp
index e2ed495230..3c99fa6593 100644
--- a/drape/overlay_handle.hpp
+++ b/drape/overlay_handle.hpp
@@ -50,6 +50,7 @@ public:
   void SetIsVisible(bool isVisible);
 
   bool IsBillboard() const;
+  virtual double GetMinScaleInPerspective() const { return 0.0; }
 
   virtual m2::PointD GetPivot(ScreenBase const & screen, bool perspective) const;
 
diff --git a/drape/overlay_tree.cpp b/drape/overlay_tree.cpp
index 17c2f1c7f6..a37aaa8216 100644
--- a/drape/overlay_tree.cpp
+++ b/drape/overlay_tree.cpp
@@ -119,6 +119,23 @@ void OverlayTree::InsertHandle(ref_ptr<OverlayHandle> handle,
 
   m2::RectD const pixelRect = handle->GetExtendedPixelRect(modelView);
 
+  bool const boundToParent = (parentOverlay.m_handle != nullptr && handle->IsBound());
+
+  if (is3dMode && handle->GetMinScaleInPerspective() > 0.0)
+  {
+    m2::RectD const pixelRect3d = handle->GetPixelRect(modelView, true);
+    m2::RectD const pixelRect2d = handle->GetPixelRect(modelView, false);
+    double const scale = min(pixelRect3d.SizeX() / pixelRect2d.SizeX(),
+                             pixelRect3d.SizeY() / pixelRect2d.SizeY());
+    if (scale < handle->GetMinScaleInPerspective())
+    {
+      // Handle is displaced and bound to its parent, parent will be displaced too.
+      if (boundToParent)
+        Erase(parentOverlay);
+      return;
+    }
+  }
+
   TOverlayContainer elements;
 
   // Find elements that already on OverlayTree and it's pixel rect
@@ -132,8 +149,6 @@ void OverlayTree::InsertHandle(ref_ptr<OverlayHandle> handle,
 
   if (handle->IsMinVisibilityTimeUp())
   {
-    bool const boundToParent = (parentOverlay.m_handle != nullptr && handle->IsBound());
-
     // If handle is bound to its parent, parent's handle will be used.
     ref_ptr<OverlayHandle> handleToCompare = handle;
     if (boundToParent)
diff --git a/drape_frontend/path_text_shape.cpp b/drape_frontend/path_text_shape.cpp
index 91bc4bc995..0c980a29f7 100644
--- a/drape_frontend/path_text_shape.cpp
+++ b/drape_frontend/path_text_shape.cpp
@@ -42,6 +42,8 @@ public:
     m_centerPointIter.Advance(mercatorOffset);
   }
 
+  double GetMinScaleInPerspective() const override { return 0.5; }
+
   bool Update(ScreenBase const & screen) override
   {
     if (!df::TextHandle::Update(screen))