From 62cba726a8cb6a2a83a426afabd3194926cb895f Mon Sep 17 00:00:00 2001
From: Tim Schubert <tim.schubert@tu-bs.de>
Date: Tue, 19 Jan 2016 22:09:14 +0100
Subject: [PATCH] Added a panning navigation mode.

---
 src/Grid.cpp | 14 ++++++++++++++
 src/Grid.hpp |  2 +-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/Grid.cpp b/src/Grid.cpp
index c84b3b8..b2191b0 100644
--- a/src/Grid.cpp
+++ b/src/Grid.cpp
@@ -271,8 +271,22 @@ void Grid::handle_event(SDL_Event *event)
     }
     if (event->type == SDL_MOUSEMOTION)
     {
+        if (this->panning)
+        {
+            SDL_Point mouse = {0, 0};
+            SDL_GetMouseState(&mouse.x, &mouse.y);
+            Point marker_pos = field_to_point(this->marker, this->layout);
+            SDL_Point p;
+            p.x = (int) marker_pos.x;
+            p.y = (int) marker_pos.y;
+            this->move(mouse - p);
+        }
         this->update_marker();
     }
+    if (event->type == SDL_MOUSEBUTTONDOWN && event->button.button == SDL_BUTTON_MIDDLE)
+    {
+        this->panning = !(this->panning);
+    }
 }
 
 void Grid::move(SDL_Point m)
diff --git a/src/Grid.hpp b/src/Grid.hpp
index 2582ef7..44de88d 100644
--- a/src/Grid.hpp
+++ b/src/Grid.hpp
@@ -173,7 +173,7 @@ protected:
     std::unordered_set<Field> *fields;
     Layout *layout;
     Field marker;
-
+    bool panning;
     bool on_rectangle(SDL_Rect *rect);
 public:
     Grid(Layout *layout_)