From 43ba6df7afe6ddf7d4dc47056aa423a0f119bc76 Mon Sep 17 00:00:00 2001
From: Mathieu Schroeter <mathieu@schroetersa.ch>
Date: Tue, 29 May 2018 18:06:04 +0200
Subject: [PATCH] Fix mostly the fullscreen switching with more than 1 display

It concerns the issue #59.

It's not perfect but it works much better (at leats on Linux). The idea
is to move the window to the top left corner of the current display.
---
 src/event.cxx | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/src/event.cxx b/src/event.cxx
index 50feb1d..f464fa0 100644
--- a/src/event.cxx
+++ b/src/event.cxx
@@ -1666,10 +1666,36 @@ CEvent::SetFullScreen (bool bFullScreen)
   SDL_SetWindowSize (g_window, LXIMAGE, LYIMAGE);
 
   g_bFullScreen = bFullScreen;
+
+  int displayIndex = SDL_GetWindowDisplayIndex (g_window);
+
+  if (g_bFullScreen)
+  {
+    int displays = SDL_GetNumVideoDisplays ();
+
+    std::vector<SDL_Rect> displayBounds;
+    for (int i = 0; i < displays; i++)
+    {
+      displayBounds.push_back (SDL_Rect ());
+      SDL_GetDisplayBounds (i, &displayBounds.back ());
+    }
+
+    /* It seems that the fullscreen switching works better when the window
+     * is at the top left corner of the current display.
+     */
+    SDL_SetWindowPosition (
+      g_window, displayBounds[displayIndex].x, displayBounds[displayIndex].y);
+  }
+
   SDL_SetWindowFullscreen (g_window, bFullScreen ? SDL_WINDOW_FULLSCREEN : 0);
   SDL_SetWindowBordered (g_window, bFullScreen ? SDL_FALSE : SDL_TRUE);
   SDL_SetWindowGrab (g_window, bFullScreen ? SDL_TRUE : SDL_FALSE);
 
+  if (!g_bFullScreen)
+    SDL_SetWindowPosition (
+      g_window, SDL_WINDOWPOS_CENTERED_DISPLAY (displayIndex),
+      SDL_WINDOWPOS_CENTERED_DISPLAY (displayIndex));
+
   m_pPixmap->LoadCursors (g_zoom);
   m_pPixmap->ReloadTargetTextures ();