Cygwin/X: Remove an attempt at detecting if WM_DISPLAYCHANGE affects the X screen

Remove an attempt at the rather difficult optimization of detecting
if WM_DISPLAYCHANGE affects any of the monitors which intersect the
native window for the X screen.

We'll always act as if it does, which it probably usually the case.

Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Reviewed-by: Colin Harrison <colin.harrison@virgin.net>
Tested-by: Colin Harrison <colin.harrison@virgin.net>

4 files changed, 31 insertions, 69 deletions

diff --git a/hw/xwin/win.h b/hw/xwin/win.h
index 8b7b69990..ceb001cd6 100644
--- a/hw/xwin/win.h
+++ b/hw/xwin/win.h
@@ -481,11 +481,6 @@ typedef struct _winPrivScreenRec
   /* Handle to icons that must be freed */
   HICON			hiconNotifyIcon;
 
-  /* Last width, height, and depth of the Windows display */
-  DWORD			dwLastWindowsWidth;
-  DWORD			dwLastWindowsHeight;
-  DWORD			dwLastWindowsBitsPixel;
-
   /* Palette management */
   ColormapPtr		pcmapInstalled;
 
diff --git a/hw/xwin/windialogs.c b/hw/xwin/windialogs.c
index 679b3fab5..c3a149762 100644
--- a/hw/xwin/windialogs.c
+++ b/hw/xwin/windialogs.c
@@ -482,11 +482,11 @@ winChangeDepthDlgProc (HWND hwndDialog, UINT message,
 
 #if CYGDEBUG
       winDebug ("winChangeDepthDlgProc - WM_INITDIALOG - orig bpp: %d, "
-	      "last bpp: %d\n",
+	      "current bpp: %d\n",
 	      s_pScreenInfo->dwBPP,
-	      s_pScreenPriv->dwLastWindowsBitsPixel);
+              GetDeviceCaps(s_pScreenPriv->hdcScreen, BITSPIXEL));
 #endif
-      
+
       winInitDialog( hwndDialog );
 
       return TRUE;
@@ -494,14 +494,13 @@ winChangeDepthDlgProc (HWND hwndDialog, UINT message,
     case WM_DISPLAYCHANGE:
 #if CYGDEBUG
       winDebug ("winChangeDepthDlgProc - WM_DISPLAYCHANGE - orig bpp: %d, "
-	      "last bpp: %d, new bpp: %d\n",
+	      "new bpp: %d\n",
 	      s_pScreenInfo->dwBPP,
-	      s_pScreenPriv->dwLastWindowsBitsPixel,
-	      wParam);
+              GetDeviceCaps(s_pScreenPriv->hdcScreen, BITSPIXEL));
 #endif
 
       /* Dismiss the dialog if the display returns to the original depth */
-      if (wParam == s_pScreenInfo->dwBPP)
+      if (GetDeviceCaps(s_pScreenPriv->hdcScreen, BITSPIXEL) == s_pScreenInfo->dwBPP)
 	{
 	  ErrorF ("winChangeDelthDlgProc - wParam == s_pScreenInfo->dwBPP\n");
 
diff --git a/hw/xwin/winscrinit.c b/hw/xwin/winscrinit.c
index 46f6693bd..74ca11557 100644
--- a/hw/xwin/winscrinit.c
+++ b/hw/xwin/winscrinit.c
@@ -175,13 +175,9 @@ winScreenInit (int index,
   /* Get a device context */
   hdc = GetDC (pScreenPriv->hwndScreen);
 
-  /* Store the initial height, width, and depth of the display */
   /* Are we using multiple monitors? */
   if (pScreenInfo->fMultipleMonitors)
     {
-      pScreenPriv->dwLastWindowsWidth = GetSystemMetrics (SM_CXVIRTUALSCREEN);
-      pScreenPriv->dwLastWindowsHeight = GetSystemMetrics (SM_CYVIRTUALSCREEN);
-
       /* 
        * In this case, some of the defaults set in
        * winInitializeScreenDefaults() are not correct ...
@@ -192,14 +188,6 @@ winScreenInit (int index,
 	  pScreenInfo->dwHeight = GetSystemMetrics (SM_CYVIRTUALSCREEN);
 	}
     }
-  else
-    {
-      pScreenPriv->dwLastWindowsWidth = GetSystemMetrics (SM_CXSCREEN);
-      pScreenPriv->dwLastWindowsHeight = GetSystemMetrics (SM_CYSCREEN);
-    }
-
-  /* Save the original bits per pixel */
-  pScreenPriv->dwLastWindowsBitsPixel = GetDeviceCaps (hdc, BITSPIXEL);
 
   /* Release the device context */
   ReleaseDC (pScreenPriv->hwndScreen, hdc);
diff --git a/hw/xwin/winwndproc.c b/hw/xwin/winwndproc.c
index 6d2270a20..7983e9aa4 100644
--- a/hw/xwin/winwndproc.c
+++ b/hw/xwin/winwndproc.c
@@ -148,6 +148,13 @@ winWindowProc (HWND hwnd, UINT message,
       return 0;
 
     case WM_DISPLAYCHANGE:
+      /*
+        WM_DISPLAYCHANGE seems to be sent when the monitor layout or
+        any monitor's resolution or depth changes, but it's lParam and
+        wParam always indicate the resolution and bpp for the primary
+        monitor (so ignore that as we could be on any monitor...)
+       */
+
       /* We cannot handle a display mode change during initialization */
       if (s_pScreenInfo == NULL)
 	FatalError ("winWindowProc - WM_DISPLAYCHANGE - The display "
@@ -167,22 +174,10 @@ winWindowProc (HWND hwnd, UINT message,
 #endif
 	      ))
 	{
-	  /* 
-	   * Store the new display dimensions and depth.
-	   * We do this here for future compatibility in case we
-	   * ever allow switching from fullscreen to windowed mode.
-	   */
-	  s_pScreenPriv->dwLastWindowsWidth = GetSystemMetrics (SM_CXSCREEN);
-	  s_pScreenPriv->dwLastWindowsHeight = GetSystemMetrics (SM_CYSCREEN);
-	  s_pScreenPriv->dwLastWindowsBitsPixel
-	    = GetDeviceCaps (s_pScreenPriv->hdcScreen, BITSPIXEL);	  
 	  break;
 	}
-      
-      ErrorF ("winWindowProc - WM_DISPLAYCHANGE - orig bpp: %d, last bpp: %d, "
-	      "new bpp: %d\n",
-	      (int) s_pScreenInfo->dwBPP,
-	      (int) s_pScreenPriv->dwLastWindowsBitsPixel,
+
+      ErrorF ("winWindowProc - WM_DISPLAYCHANGE - new bpp: %d\n",
 	      wParam);
 
       ErrorF ("winWindowProc - WM_DISPLAYCHANGE - new width: %d "
@@ -216,7 +211,11 @@ winWindowProc (HWND hwnd, UINT message,
        * We can only display a message for a disruptive depth change,
        * we cannot do anything to correct the situation.
        */
-      if ((s_pScreenInfo->dwBPP != wParam)
+      /*
+        XXX: maybe we need to check if GetSystemMetrics(SM_SAMEDISPLAYFORMAT)
+        has changed as well...
+      */
+      if ((s_pScreenInfo->dwBPP != GetDeviceCaps (s_pScreenPriv->hdcScreen, BITSPIXEL))
 	  && (s_pScreenInfo->dwEngine == WIN_SERVER_SHADOW_DD
 	      || s_pScreenInfo->dwEngine == WIN_SERVER_SHADOW_DDNL
 #ifdef XWIN_PRIMARYFB
@@ -227,7 +226,7 @@ winWindowProc (HWND hwnd, UINT message,
 	  /* Cannot display the visual until the depth is restored */
 	  ErrorF ("winWindowProc - Disruptive change in depth\n");
 
-	  /* Display Exit dialog */
+	  /* Display depth change dialog */
 	  winDisplayDepthChangeDialog (s_pScreenPriv);
 
 	  /* Flag that we have an invalid screen depth */
@@ -241,14 +240,19 @@ winWindowProc (HWND hwnd, UINT message,
 	  /* Flag that we have a valid screen depth */
 	  s_pScreenPriv->fBadDepth = FALSE;
 	}
-      
+
+      /*
+        If we could cheaply check if this WM_DISPLAYCHANGE change
+        affects the monitor(s) which this X screen is displayed on
+        then we should do so here.  For the moment, assume it does.
+        (this is probably usually the case so that might be an
+        overoptimization)
+      */
+
       /*
-       * Check for a change in display dimensions.
        * We can simply recreate the same-sized primary surface when
        * the display dimensions change.
        */
-      if (s_pScreenPriv->dwLastWindowsWidth != LOWORD (lParam)
-	  || s_pScreenPriv->dwLastWindowsHeight != HIWORD (lParam))
 	{
 	  /*
 	   * NOTE: The non-DirectDraw engines set the ReleasePrimarySurface
@@ -261,7 +265,7 @@ winWindowProc (HWND hwnd, UINT message,
 #if CYGDEBUG
 	  winDebug ("winWindowProc - WM_DISPLAYCHANGE - Dimensions changed\n");
 #endif
-	  
+
 	  /* Release the old primary surface */
 	  (*s_pScreenPriv->pwinReleasePrimarySurface) (s_pScreen);
 
@@ -286,31 +290,7 @@ winWindowProc (HWND hwnd, UINT message,
 	    }
 #endif
 	}
-      else
-	{
-#if CYGDEBUG
-	  winDebug ("winWindowProc - WM_DISPLAYCHANGE - Dimensions did not "
-		  "change\n");
-#endif
-	}
 
-      /* Store the new display dimensions and depth */
-      if (s_pScreenInfo->fMultipleMonitors)
-	{
-	  s_pScreenPriv->dwLastWindowsWidth
-	    = GetSystemMetrics (SM_CXVIRTUALSCREEN);
-	  s_pScreenPriv->dwLastWindowsHeight
-	    = GetSystemMetrics (SM_CYVIRTUALSCREEN);
-	}
-      else
-	{
-	  s_pScreenPriv->dwLastWindowsWidth
-	    = GetSystemMetrics (SM_CXSCREEN);
-	  s_pScreenPriv->dwLastWindowsHeight
-	    = GetSystemMetrics (SM_CYSCREEN);
-	}
-      s_pScreenPriv->dwLastWindowsBitsPixel
-	= GetDeviceCaps (s_pScreenPriv->hdcScreen, BITSPIXEL);
       break;
 
     case WM_SIZE: