Implement letter- and windowboxing for GDI

main.c

@@ -265,6 +265,7 @@ HRESULT __stdcall ddraw_SetDisplayMode(IDirectDrawImpl *This, DWORD width, DWORD
 
 LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 {
+    RECT rc = { 0, 0, ddraw->render.width, ddraw->render.height };
     POINT pt;
 
     switch(uMsg)
@@ -372,6 +373,12 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
                 return ddraw->WndProc(hWnd, uMsg, wParam, MAKELPARAM(pt.x, pt.y));
             }
             return ddraw->WndProc(hWnd, uMsg, wParam, lParam);
+
+        case WM_ERASEBKGND:
+            EnterCriticalSection(&ddraw->cs);
+            FillRect(ddraw->render.hDC, &rc, (HBRUSH) GetStockObject(BLACK_BRUSH));
+            LeaveCriticalSection(&ddraw->cs);
+            return TRUE;
     }
 
     return DefWindowProc(hWnd, uMsg, wParam, lParam);
@@ -601,6 +608,8 @@ HRESULT WINAPI DirectDrawCreate(GUID FAR* lpGUID, LPDIRECTDRAW FAR* lplpDD, IUnk
             "windowed=true\n"
             "; show window borders in windowed mode\n"
             "border=true\n"
+            "; use letter- or windowboxing to make a best fit (GDI only!)\n"
+            "boxing=false\n"
             "; real rendering rate, -1 = screen rate, 0 = unlimited, n = cap\n"
             "maxfps=0\n"
             "; vertical synchronization, enable if you get tearing (OpenGL only)\n"
@@ -641,6 +650,16 @@ HRESULT WINAPI DirectDrawCreate(GUID FAR* lpGUID, LPDIRECTDRAW FAR* lplpDD, IUnk
         This->border = TRUE;
     }
 
+    GetPrivateProfileStringA("ddraw", "boxing", "FALSE", tmp, sizeof(tmp), ini_path);
+    if(tolower(tmp[0]) == 'n' || tolower(tmp[0]) == 'f' || tmp[0] == '0')
+    {
+        This->boxing = FALSE;
+    }
+    else
+    {
+        This->boxing = TRUE;
+    }
+
     This->render.maxfps = GetPrivateProfileIntA("ddraw", "maxfps", 0, ini_path);
     This->render.width = GetPrivateProfileIntA("ddraw", "width", 640, ini_path);
     if(This->render.width < 640)

main.h

@@ -39,6 +39,7 @@ typedef struct IDirectDrawImpl
     DWORD bpp;
     BOOL windowed;
     BOOL border;
+    BOOL boxing;
     BOOL windowed_init;
     DEVMODE mode;
     struct IDirectDrawSurfaceImpl *primary;

render.c

@@ -99,6 +99,7 @@ DWORD WINAPI render_main(void)
 
         /* convert ddraw surface to opengl texture */
         EnterCriticalSection(&ddraw->cs);
+
         if(ddraw->primary && ddraw->primary->palette)
         {
             if(ddraw->vhack && detect_cutscene())

render_soft.c

@@ -31,10 +31,31 @@ DWORD WINAPI render_soft_main(void)
     bmi->bmiHeader.biBitCount = ddraw->bpp;
     bmi->bmiHeader.biCompression = BI_RGB;
 
+    DWORD dst_top = 0;
+    DWORD dst_left = 0;
+    DWORD dst_width = ddraw->render.width;
+    DWORD dst_height = ddraw->render.height;
+
     DWORD tick_start = 0;
     DWORD tick_end = 0;
     DWORD frame_len = 0;
 
+    if (ddraw->boxing)
+    {
+        dst_width = ddraw->width;
+        dst_height = ddraw->height;
+
+        /* test if we can double scale the window */
+        if (ddraw->width * 2 <= ddraw->render.width && ddraw->height * 2 <= ddraw->render.height)
+        {
+            dst_width *= 2;
+            dst_height *= 2;
+        }
+
+        dst_top = ddraw->render.height / 2 - dst_height / 2;
+        dst_left = ddraw->render.width / 2 - dst_width / 2;
+    }
+
     if(ddraw->render.maxfps < 0)
     {
         ddraw->render.maxfps = ddraw->mode.dmDisplayFrequency;
@@ -53,6 +74,7 @@ DWORD WINAPI render_soft_main(void)
         }
 
         EnterCriticalSection(&ddraw->cs);
+
         if (ddraw->primary && (ddraw->primary->palette || ddraw->bpp == 16))
         {
             if (ddraw->primary->palette && ddraw->primary->palette->data_rgb == NULL)
@@ -62,7 +84,7 @@ DWORD WINAPI render_soft_main(void)
 
             if (ddraw->render.width != ddraw->width || ddraw->render.height != ddraw->height)
             {
-                StretchDIBits(ddraw->render.hDC, 0, 0, ddraw->render.width, ddraw->render.height, 0, 0, ddraw->width, ddraw->height, ddraw->primary->surface, bmi, DIB_RGB_COLORS, SRCCOPY);
+                StretchDIBits(ddraw->render.hDC, dst_left, dst_top, dst_width, dst_height, 0, 0, ddraw->width, ddraw->height, ddraw->primary->surface, bmi, DIB_RGB_COLORS, SRCCOPY);
             }
             else
             {