--- a/tools/64vw.c	Mon Nov 27 09:21:29 2023 +0200
+++ b/tools/64vw.c	Mon Nov 27 10:14:07 2023 +0200
@@ -17,8 +17,8 @@
 #define SET_SKIP_AMOUNT 10
 
 
-int     optVFlags = 0;
-int     optScrWidth, optScrHeight;
+int     optWindowFlags = 0;
+int     optSetWindowWidth, optSetWindowHeight;
 int     optForcedFormat = -1;
 bool    optInfoOnly  = false,
         optProbeOnly = false,
@@ -54,8 +54,8 @@
 
 void dmSetScaleFactor(float factor)
 {
-    optScrWidth = (int) ((float) D64_SCR_WIDTH * factor * D64_SCR_PAR_XY);
-    optScrHeight = (int) ((float) D64_SCR_HEIGHT * factor);
+    optSetWindowWidth = (int) ((float) D64_SCR_WIDTH * factor * D64_SCR_PAR_XY);
+    optSetWindowHeight = (int) ((float) D64_SCR_HEIGHT * factor);
 }
 
 
@@ -102,7 +102,7 @@
             break;
 
         case 10:
-            optVFlags |= SDL_WINDOW_FULLSCREEN_DESKTOP;
+            optWindowFlags |= SDL_WINDOW_FULLSCREEN_DESKTOP;
             break;
 
         case 12:
@@ -273,8 +273,9 @@
     SDL_Texture *texture = NULL;
     SDL_Surface *surf = NULL;
     DMImage *bimage = NULL;
-    bool initSDL = false, exitFlag, needRedraw;
+    bool initSDL = false, exitFlag, needRedraw, allowResize;
     size_t currIndex, prevIndex;
+    int currWindowWidth, currWindowHeight;
     int res = DMERR_OK;
 
     // Initialize pre-requisites
@@ -427,8 +428,8 @@
     // Open window
     if ((window = SDL_CreateWindow(dmProgName,
         SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
-        optScrWidth, optScrHeight,
-        optVFlags | SDL_WINDOW_RESIZABLE
+        optSetWindowWidth, optSetWindowHeight,
+        optWindowFlags | SDL_WINDOW_RESIZABLE
         //| SDL_WINDOW_HIDDEN
         )) == NULL)
     {
@@ -445,9 +446,12 @@
 //    SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "best");
 
     // Start main loop
+    currWindowWidth = optSetWindowWidth;
+    currWindowHeight = optSetWindowHeight;
     currIndex = 0;
     prevIndex = 1;
     needRedraw = true;
+    allowResize = true;
     exitFlag = false;
     while (!exitFlag)
     {
@@ -503,9 +507,16 @@
                         break;
 
                     case SDLK_f:
-                        optVFlags ^= SDL_WINDOW_FULLSCREEN_DESKTOP;
-                        if (SDL_SetWindowFullscreen(window, optVFlags) != 0)
+                        // If we switch to/from fullscreen, set a flag so we do not
+                        // use the fullscreen window size as new stored window size
+                        allowResize = false;
+                        optWindowFlags ^= SDL_WINDOW_FULLSCREEN_DESKTOP;
+
+                        if (SDL_SetWindowFullscreen(window, optWindowFlags) != 0)
                             goto out;
+
+                        if ((optWindowFlags & SDL_WINDOW_FULLSCREEN_DESKTOP) == 0)
+                            SDL_SetWindowSize(window, optSetWindowWidth, optSetWindowHeight);
                         break;
 
                     default:
@@ -523,9 +534,14 @@
                         break;
 
                     case SDL_WINDOWEVENT_RESIZED:
-                        optScrWidth  = event.window.data1;
-                        optScrHeight = event.window.data2;
-
+                        if (allowResize)
+                        {
+                            optSetWindowWidth  = event.window.data1;
+                            optSetWindowHeight = event.window.data2;
+                        }
+                        currWindowWidth = event.window.data1;
+                        currWindowHeight = event.window.data2;
+                        allowResize = true;
                         needRedraw = true;
                         break;
                 }
@@ -542,6 +558,7 @@
             DMC64Image *cimage = NULL;
             char *title = NULL;
 
+            // Delete previous surface if any
             if (surf != NULL)
             {
                 SDL_FreeSurface(surf);
@@ -570,7 +587,7 @@
                 goto fail;
             }
 
-            // Create surface (we are lazy and ugly)
+            // Convert image to surface (we are lazy and ugly)
             if (dmConvertC64ImageToSDLSurface(&bimage, &surf, cimage, &optSpec) == DMERR_OK)
             {
                 title = dm_strdup_printf("%s - [%d / %d] %s (%dx%d @ %s)",
@@ -591,6 +608,7 @@
 fail:
             dmC64ImageFree(cimage);
 
+            // Create or update surface and texture
             if (surf == NULL && (surf = SDL_CreateRGBSurfaceWithFormat(0,
                 D64_SCR_WIDTH, D64_SCR_HEIGHT, 8, SDL_PIXELFORMAT_INDEX8)) == NULL)
             {
@@ -607,6 +625,7 @@
                 goto out;
             }
 
+            // Create stub title string if we didn't manage to decode the image
             if (title == NULL)
             {
                 title = dm_strdup_printf("%s - [%d / %d] %s",
@@ -625,13 +644,20 @@
 
         if (needRedraw)
         {
+            // Calculate the render size
+            SDL_Rect dstRect;
+            dstRect.w = (((float) currWindowHeight) * D64_SCR_FULL_WIDTH / D64_SCR_FULL_HEIGHT / D64_SCR_PAR_XY);
+            dstRect.h = currWindowHeight;
+            dstRect.x = (currWindowWidth - dstRect.w) / 2;
+            dstRect.y = 0;
+
             SDL_RenderClear(renderer);
-            SDL_RenderCopy(renderer, texture, NULL, NULL);
+            SDL_RenderCopy(renderer, texture, NULL, &dstRect);
             SDL_RenderPresent(renderer);
             needRedraw = false;
         }
-
-        SDL_Delay(50);
+        else
+            SDL_Delay(50);
     }
 
 out: