Cygwin/X: Deal with RANDR depth changes correctly in ShadowGDI drawing engine

Make ShadowGDI drawing engine only change the size of the screen
pixmap/shadow framebuffer on an RANDR change, not the bpp/depth
as well.

The server requires the screen pixmap's depth to be invariant.

Other drawing engines aren't quite as affected by this issue as
they won't draw to the display, if it has changed colour depth,
but probably still need some attention.

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, 60 insertions, 70 deletions

diff --git a/hw/xwin/win.h b/hw/xwin/win.h
index 96a868e22..3f40fdbe0 100644
--- a/hw/xwin/win.h
+++ b/hw/xwin/win.h
@@ -504,7 +504,8 @@ typedef struct _winPrivScreenRec
   HDC			hdcScreen;
   HDC			hdcShadow;
   HWND			hwndScreen;
-  
+  BITMAPINFOHEADER      *pbmih;
+
   /* Privates used by shadow fb and primary fb DirectDraw servers */
   LPDIRECTDRAW		pdd;
   LPDIRECTDRAWSURFACE2	pddsPrimary;
diff --git a/hw/xwin/winscrinit.c b/hw/xwin/winscrinit.c
index f505dddca..699ed949e 100644
--- a/hw/xwin/winscrinit.c
+++ b/hw/xwin/winscrinit.c
@@ -126,7 +126,7 @@ winScreenInit (int index,
       return FALSE;
     }
 
-  /* Adjust the video mode for our engine type */
+  /* Horribly misnamed function: Allow engine to adjust BPP for screen */
   if (!(*pScreenPriv->pwinAdjustVideoMode) (pScreen))
     {
       ErrorF ("winScreenInit - winAdjustVideoMode () failed\n");
@@ -269,7 +269,8 @@ winFinishScreenInitFB (int index,
     }
 
   /*
-   * Grab the number of bits that are used to represent color in each pixel.
+   * Calculate the number of bits that are used to represent color in each pixel,
+   * the color depth for the screen
    */
   if (pScreenInfo->dwBPP == 8)
     pScreenInfo->dwDepth = 8;
@@ -277,7 +278,7 @@ winFinishScreenInitFB (int index,
     pScreenInfo->dwDepth = winCountBits (pScreenPriv->dwRedMask)
       + winCountBits (pScreenPriv->dwGreenMask)
       + winCountBits (pScreenPriv->dwBlueMask);
-  
+
   winErrorFVerb (2, "winFinishScreenInitFB - Masks: %08x %08x %08x\n",
 	  (unsigned int) pScreenPriv->dwRedMask,
 	  (unsigned int) pScreenPriv->dwGreenMask,
diff --git a/hw/xwin/winshadgdi.c b/hw/xwin/winshadgdi.c
index 721234eee..e9c51ee64 100644
--- a/hw/xwin/winshadgdi.c
+++ b/hw/xwin/winshadgdi.c
@@ -338,33 +338,20 @@ winAllocateFBShadowGDI (ScreenPtr pScreen)
 {
   winScreenPriv(pScreen);
   winScreenInfo		*pScreenInfo = pScreenPriv->pScreenInfo;
-  BITMAPINFOHEADER	*pbmih = NULL;
   DIBSECTION		dibsection;
   Bool			fReturn = TRUE;
 
-  /* Allocate bitmap info header */
-  pbmih = (BITMAPINFOHEADER*) malloc (sizeof (BITMAPINFOHEADER)
-				      + 256 * sizeof (RGBQUAD));
-  if (pbmih == NULL)
-    {
-      ErrorF ("winAllocateFBShadowGDI - malloc () failed\n");
-      return FALSE;
-    }
-
-  /* Query the screen format */
-  fReturn = winQueryScreenDIBFormat (pScreen, pbmih);
-
   /* Describe shadow bitmap to be created */
-  pbmih->biWidth = pScreenInfo->dwWidth;
-  pbmih->biHeight = -pScreenInfo->dwHeight;
-  
+  pScreenPriv->pbmih->biWidth = pScreenInfo->dwWidth;
+  pScreenPriv->pbmih->biHeight = -pScreenInfo->dwHeight;
+
   ErrorF ("winAllocateFBShadowGDI - Creating DIB with width: %d height: %d "
 	  "depth: %d\n",
-	  (int) pbmih->biWidth, (int) -pbmih->biHeight, pbmih->biBitCount);
+	  (int) pScreenPriv->pbmih->biWidth, (int) -pScreenPriv->pbmih->biHeight, pScreenPriv->pbmih->biBitCount);
 
   /* Create a DI shadow bitmap with a bit pointer */
   pScreenPriv->hbmpShadow = CreateDIBSection (pScreenPriv->hdcScreen,
-					      (BITMAPINFO *) pbmih,
+					      (BITMAPINFO *) pScreenPriv->pbmih,
 					      DIB_RGB_COLORS,
 					      (VOID**) &pScreenInfo->pfb,
 					      NULL,
@@ -445,13 +432,6 @@ winAllocateFBShadowGDI (ScreenPtr pScreen)
 	  (int) pScreenInfo->dwStride);
 #endif
 
-  /* Determine our color masks */
-  if (!winQueryRGBBitsAndMasks (pScreen))
-    {
-      ErrorF ("winAllocateFBShadowGDI - winQueryRGBBitsAndMasks failed\n");
-      return FALSE;
-    }
-
 #ifdef XWIN_MULTIWINDOW
   /* Redraw all windows */
   if (pScreenInfo->fMultiWindow)
@@ -607,6 +587,29 @@ winInitScreenShadowGDI (ScreenPtr pScreen)
   pScreenPriv->hdcScreen = GetDC (pScreenPriv->hwndScreen);
   pScreenPriv->hdcShadow = CreateCompatibleDC (pScreenPriv->hdcScreen);
 
+  /* Allocate bitmap info header */
+  pScreenPriv->pbmih = (BITMAPINFOHEADER*) malloc (sizeof (BITMAPINFOHEADER)
+                                                   + 256 * sizeof (RGBQUAD));
+  if (pScreenPriv->pbmih == NULL)
+    {
+      ErrorF ("winInitScreenShadowGDI - malloc () failed\n");
+      return FALSE;
+    }
+
+  /* Query the screen format */
+  if (!winQueryScreenDIBFormat (pScreen, pScreenPriv->pbmih))
+    {
+      ErrorF ("winInitScreenShadowGDI - winQueryScreenDIBFormat failed\n");
+      return FALSE;
+    }
+
+  /* Determine our color masks */
+  if (!winQueryRGBBitsAndMasks (pScreen))
+    {
+      ErrorF ("winInitScreenShadowGDI - winQueryRGBBitsAndMasks failed\n");
+      return FALSE;
+    }
+
   return winAllocateFBShadowGDI(pScreen);
 }
 
diff --git a/hw/xwin/winwndproc.c b/hw/xwin/winwndproc.c
index 80f5e1a7b..dd8f27edb 100644
--- a/hw/xwin/winwndproc.c
+++ b/hw/xwin/winwndproc.c
@@ -183,28 +183,6 @@ winWindowProc (HWND hwnd, UINT message,
 	      LOWORD (lParam), HIWORD (lParam), wParam);
 
       /*
-       * TrueColor --> TrueColor depth changes are disruptive for:
-       *	Windowed:
-       *		Shadow DirectDraw
-       *		Shadow DirectDraw Non-Locking
-       *		Primary DirectDraw
-       *
-       * TrueColor --> TrueColor depth changes are non-optimal for:
-       *	Windowed:
-       *		Shadow GDI
-       *
-       *	FullScreen:
-       *		Shadow GDI
-       *
-       * TrueColor --> PseudoColor or vice versa are disruptive for:
-       *	Windowed:
-       *		Shadow DirectDraw
-       *		Shadow DirectDraw Non-Locking
-       *		Primary DirectDraw
-       *		Shadow GDI
-       */
-
-      /*
        * Check for a disruptive change in depth.
        * We can only display a message for a disruptive depth change,
        * we cannot do anything to correct the situation.
@@ -213,31 +191,38 @@ winWindowProc (HWND hwnd, UINT message,
         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
+      if (s_pScreenInfo->dwBPP != GetDeviceCaps (s_pScreenPriv->hdcScreen, BITSPIXEL))
+        {
+          if ((s_pScreenInfo->dwEngine == WIN_SERVER_SHADOW_DD
+               || s_pScreenInfo->dwEngine == WIN_SERVER_SHADOW_DDNL
 #ifdef XWIN_PRIMARYFB
-	      || s_pScreenInfo->dwEngine == WIN_SERVER_PRIMARY_DD
+               || s_pScreenInfo->dwEngine == WIN_SERVER_PRIMARY_DD
 #endif
-	      ))
-	{
-	  /* Cannot display the visual until the depth is restored */
-	  ErrorF ("winWindowProc - Disruptive change in depth\n");
+               ))
+            {
+              /* Cannot display the visual until the depth is restored */
+              ErrorF ("winWindowProc - Disruptive change in depth\n");
 
-	  /* Display depth change dialog */
-	  winDisplayDepthChangeDialog (s_pScreenPriv);
+              /* Display depth change dialog */
+              winDisplayDepthChangeDialog (s_pScreenPriv);
 
-	  /* Flag that we have an invalid screen depth */
-	  s_pScreenPriv->fBadDepth = TRUE;
+              /* Flag that we have an invalid screen depth */
+              s_pScreenPriv->fBadDepth = TRUE;
 
-	  /* Minimize the display window */
-	  ShowWindow (hwnd, SW_MINIMIZE);
-	}
+              /* Minimize the display window */
+              ShowWindow (hwnd, SW_MINIMIZE);
+            }
+          else
+            {
+              /* For GDI, performance may suffer until original depth is restored */
+              ErrorF ("winWindowProc - Performance may be non-optimal after change in depth\n");
+            }
+        }
       else
-	{
-	  /* Flag that we have a valid screen depth */
-	  s_pScreenPriv->fBadDepth = FALSE;
-	}
+        {
+          /* Flag that we have a valid screen depth */
+          s_pScreenPriv->fBadDepth = FALSE;
+        }
 
       /*
         If we could cheaply check if this WM_DISPLAYCHANGE change