From 375388b22f74707a0588de098d847bbf9959344f Mon Sep 17 00:00:00 2001
From: Mathieu Schroeter <mathieu@schroetersa.ch>
Date: Mon, 25 Jun 2018 22:17:39 +0200
Subject: [PATCH] Fix mouse position when changing zoom and fullscreen

---
 src/blupi.cxx  |  5 ++++-
 src/event.cxx  | 38 ++++++++++++++++++++++++++------------
 src/event.h    |  2 +-
 src/pixmap.cxx | 24 ++++++++++++------------
 src/pixmap.h   |  2 +-
 5 files changed, 44 insertions(+), 27 deletions(-)

diff --git a/src/blupi.cxx b/src/blupi.cxx
index 9ecdc61..58a897e 100644
--- a/src/blupi.cxx
+++ b/src/blupi.cxx
@@ -410,7 +410,10 @@ HandleEvent (const SDL_Event & event)
     case EV_WARPMOUSE:
     {
       const SDL_Point * coord = static_cast<SDL_Point *> (event.user.data1);
-      SDL_WarpMouseInWindow (g_window, coord->x, coord->y);
+
+      Sint32 x = coord->x, y = coord->y;
+      g_pPixmap->FromGameToDisplay (x, y);
+      SDL_WarpMouseInWindow (g_window, x, y);
       delete coord;
       break;
     }
diff --git a/src/event.cxx b/src/event.cxx
index 510bfef..9ca08b0 100644
--- a/src/event.cxx
+++ b/src/event.cxx
@@ -1723,6 +1723,10 @@ CEvent::GetMousePos ()
 void
 CEvent::SetFullScreen (bool bFullScreen)
 {
+  int x, y;
+  SDL_GetMouseState (&x, &y);
+  this->m_pPixmap->FromDisplayToGame (x, y);
+
   g_bFullScreen = bFullScreen;
 
   int displayIndex = 0;
@@ -1762,12 +1766,15 @@ CEvent::SetFullScreen (bool bFullScreen)
 
   m_pPixmap->LoadCursors ();
 
-  if (g_bFullScreen)
-  {
-    Sint32 w, h;
-    SDL_GetWindowSize (g_window, &w, &h);
-    SDL_WarpMouseGlobal (w / 2, h / 2);
-  }
+  /* Force this update before otherwise the coordinates retrieved with
+   * the Warp SDL function are corresponding to the previous size.
+   */
+  CEvent::PushUserEvent (EV_UPDATE);
+
+  auto coord = new SDL_Point; // Released by the event handler.
+  coord->x   = x;
+  coord->y   = y;
+  CEvent::PushUserEvent (EV_WARPMOUSE, coord);
 }
 
 /**
@@ -1803,10 +1810,11 @@ CEvent::SetWindowSize (Uint8 newScale)
  * \param[in] newScale - The new scale.
  */
 void
-CEvent::SetWindowSize (Uint8 prevScale, Uint8 newScale)
+CEvent::SetWindowSize (double prevScale, double newScale)
 {
   int x, y;
   SDL_GetMouseState (&x, &y);
+  this->m_pPixmap->FromDisplayToGame (x, y, prevScale);
 
   if (g_bFullScreen && newScale == 2)
     newScale = 1;
@@ -1829,8 +1837,8 @@ CEvent::SetWindowSize (Uint8 prevScale, Uint8 newScale)
   CEvent::PushUserEvent (EV_UPDATE);
 
   auto coord = new SDL_Point; // Released by the event handler.
-  coord->x   = newScale < prevScale ? x / prevScale : x * newScale;
-  coord->y   = newScale < prevScale ? y / prevScale : x * newScale;
+  coord->x   = x;
+  coord->y   = y;
   CEvent::PushUserEvent (EV_WARPMOUSE, coord);
 }
 
@@ -4245,16 +4253,21 @@ CEvent::ChangeButtons (Sint32 message)
       break;
     }
     case EV_BUTTON4:
+    {
+      Sint32 w1;
+      SDL_GetWindowSize (g_window, &w1, nullptr);
       SetFullScreen (false);
-      SetWindowSize (g_zoom, g_zoom);
+      SetWindowSize (g_zoom * static_cast<double> (w1) / LXIMAGE, g_zoom);
       break;
+    }
     case EV_BUTTON5:
     {
       auto scale = g_zoom;
       if (g_zoom > 1)
         --g_zoom;
       SetWindowSize (scale, g_zoom);
-      SetFullScreen (g_bFullScreen);
+      if (g_bFullScreen)
+        SetFullScreen (g_bFullScreen);
       break;
     }
     case EV_BUTTON6:
@@ -4263,7 +4276,8 @@ CEvent::ChangeButtons (Sint32 message)
       if (g_zoom < 2)
         ++g_zoom;
       SetWindowSize (scale, g_zoom);
-      SetFullScreen (g_bFullScreen);
+      if (g_bFullScreen)
+        SetFullScreen (g_bFullScreen);
       break;
     }
     case EV_BUTTON7:
diff --git a/src/event.h b/src/event.h
index 1f4b1cd..2cd6db3 100644
--- a/src/event.h
+++ b/src/event.h
@@ -167,7 +167,7 @@ protected:
   Language GetStartLanguage ();
   Language GetLanguage ();
   void     SetLanguage (Language lang = Language::undef);
-  void     SetWindowSize (Uint8 prevScale, Uint8 newScale);
+  void     SetWindowSize (double prevScale, double newScale);
 
   void ChangeButtons (Sint32 message);
 
diff --git a/src/pixmap.cxx b/src/pixmap.cxx
index 606782c..87177b6 100644
--- a/src/pixmap.cxx
+++ b/src/pixmap.cxx
@@ -979,24 +979,24 @@ CPixmap::GetDisplayScale ()
 }
 
 void
-CPixmap::FromDisplayToGame (Sint32 & x, Sint32 & y)
+CPixmap::FromDisplayToGame (Sint32 & x, Sint32 & y, double prevScale)
 {
   if (this->event->IsDemoPlaying ())
     return;
 
-  SDL_DisplayMode displayMode;
-  SDL_GetWindowDisplayMode (g_window, &displayMode);
+  Sint32 w, h;
+  SDL_GetWindowSize (g_window, &w, &h);
 
-  if (
-    static_cast<double> (displayMode.w) / displayMode.h ==
-    static_cast<double> (SCRNUM) / SCRDEN)
+  double factor = 1;
+
+  if (!g_bFullScreen)
+    factor = prevScale;
+
+  x /= factor;
+  y /= factor;
+
+  if (!g_bFullScreen)
     return;
-
-  double w = displayMode.w, h = displayMode.h;
-  double ratio = w * SCRDEN / SCRNUM;
-
-  x = (x - (w - ratio) / 2) / (ratio / LXIMAGE);
-  y = y / (h / LYIMAGE);
 }
 
 void
diff --git a/src/pixmap.h b/src/pixmap.h
index 0b315fa..3b660da 100644
--- a/src/pixmap.h
+++ b/src/pixmap.h
@@ -95,7 +95,7 @@ public:
 
 public:
   double GetDisplayScale ();
-  void   FromDisplayToGame (Sint32 & x, Sint32 & y);
+  void   FromDisplayToGame (Sint32 & x, Sint32 & y, double prevScale = 1);
   void   FromGameToDisplay (Sint32 & x, Sint32 & y);
 
 protected: