Make the editor window resizable and fill it with the (wrapping) map

CGame.h

@@ -74,6 +74,9 @@ class CGame
 
     bool Init();
     bool ReCreateWindow();
+    /// Resize the render target (display surface + texture) to the given size, e.g. after the user resized or maximized
+    /// the window. Keeps the existing window and renderer, so it is cheap enough to call while dragging the border.
+    bool ResizeDisplay(Extent newSize);
 
     void EventHandling(SDL_Event* Event);
 

CGame_Event.cpp

@@ -377,6 +377,19 @@ void CGame::EventHandling(SDL_Event* Event)
             break;
         }
 
+        case SDL_WINDOWEVENT:
+        {
+            // Follow user-driven window resizing/maximizing by growing the editor's working area, just like the
+            // game client does. The map view and menus re-derive their surfaces from GameResolution.
+            if(Event->window.event == SDL_WINDOWEVENT_SIZE_CHANGED && !fullscreen)
+            {
+                const Extent newSize(Event->window.data1, Event->window.data2);
+                if(newSize != GameResolution)
+                    ResizeDisplay(newSize);
+            }
+            break;
+        }
+
         case SDL_QUIT: Running = false; break;
 
         default: break;

CGame_Init.cpp

@@ -22,22 +22,33 @@ bool CGame::ReCreateWindow()
     window_.reset();
     window_.reset(SDL_CreateWindow("Return to the Roots Map editor [BETA]", SDL_WINDOWPOS_CENTERED,
                                    SDL_WINDOWPOS_CENTERED, GameResolution.x, GameResolution.y,
-                                   fullscreen ? SDL_WINDOW_FULLSCREEN : 0));
+                                   fullscreen ? SDL_WINDOW_FULLSCREEN : SDL_WINDOW_RESIZABLE));
     if(!window_)
         return false;
+    // Don't allow shrinking below the smallest resolution we have a dedicated map frame for
+    SDL_SetWindowMinimumSize(window_.get(), 640, 480);
     renderer_.reset(SDL_CreateRenderer(window_.get(), -1, 0));
     if(!renderer_)
         return false;
-    displayTexture_ = makeSdlTexture(renderer_, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_STREAMING, GameResolution.x,
-                                     GameResolution.y);
-    Surf_Display = makeRGBSurface(GameResolution.x, GameResolution.y, true);
-    if(!displayTexture_ || !Surf_Display)
+    if(!ResizeDisplay(GameResolution))
         return false;
 
     SetAppIcon();
     return true;
 }
 
+bool CGame::ResizeDisplay(Extent newSize)
+{
+    // Ignore degenerate sizes, e.g. while the window is minimized
+    if(newSize.x == 0 || newSize.y == 0)
+        return true;
+    GameResolution = newSize;
+    displayTexture_ =
+      makeSdlTexture(renderer_, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_STREAMING, newSize.x, newSize.y);
+    Surf_Display = makeRGBSurface(newSize.x, newSize.y, true);
+    return displayTexture_ && Surf_Display;
+}
+
 bool CGame::Init()
 {
     std::cout << "Return to the Roots Map editor\n";