Fix major DC suckage on win2k and 98. Instead of calling GetDC all the time,

only call it when we need it and then be sure to release it. r=mjudge, bug#49285

gfx/src/windows/nsScreenManagerWin.cpp

@@ -107,7 +107,7 @@ NS_IMPL_ISUPPORTS(nsScreenManagerWin, NS_GET_IID(nsIScreenManager))
 //        screen. This should change when a multi-monitor impl is done.
 //
 nsIScreen* 
-nsScreenManagerWin :: CreateNewScreenObject ( HDC inContext, void* inScreen )
+nsScreenManagerWin :: CreateNewScreenObject ( void* inScreen )
 {
   nsIScreen* retScreen = nsnull;
   
@@ -121,7 +121,7 @@ nsScreenManagerWin :: CreateNewScreenObject ( HDC inContext, void* inScreen )
     }
   } // for each screen.
  
-  retScreen = new nsScreenWin(inContext, inScreen);
+  retScreen = new nsScreenWin(inScreen);
   ScreenListItem* listItem = new ScreenListItem ( (HMONITOR)inScreen, retScreen );
   mScreenList.AppendElement ( listItem );
 
@@ -144,7 +144,7 @@ nsScreenManagerWin :: ScreenForRect ( PRInt32 inLeft, PRInt32 inTop, PRInt32 inW
 {
   if ( !(inWidth || inHeight) ) {
     NS_WARNING ( "trying to find screen for sizeless window, using primary monitor" );
-    *outScreen = CreateNewScreenObject ( ::GetDC(nsnull), nsnull );    // addrefs
+    *outScreen = CreateNewScreenObject ( nsnull );    // addrefs
     return NS_OK;
   }
 
@@ -161,7 +161,7 @@ nsScreenManagerWin :: ScreenForRect ( PRInt32 inLeft, PRInt32 inTop, PRInt32 inW
   }
 #endif
 
-  *outScreen = CreateNewScreenObject ( ::GetDC(nsnull), genScreen );    // addrefs
+  *outScreen = CreateNewScreenObject ( genScreen );    // addrefs
   
   return NS_OK;
     
@@ -177,7 +177,7 @@ nsScreenManagerWin :: ScreenForRect ( PRInt32 inLeft, PRInt32 inTop, PRInt32 inW
 NS_IMETHODIMP 
 nsScreenManagerWin :: GetPrimaryScreen(nsIScreen** aPrimaryScreen) 
 {
-  *aPrimaryScreen = CreateNewScreenObject ( ::GetDC(nsnull), nsnull );    // addrefs  
+  *aPrimaryScreen = CreateNewScreenObject ( nsnull );    // addrefs  
   return NS_OK;
   
 } // GetPrimaryScreen

gfx/src/windows/nsScreenManagerWin.h

@@ -45,7 +45,7 @@ public:
 
 private:
 
-  nsIScreen* CreateNewScreenObject ( HDC inContext, void* inScreen ) ;
+  nsIScreen* CreateNewScreenObject ( void* inScreen ) ;
 
   PRBool mHasMultiMonitorAPIs;
   PRUint32 mNumberOfScreens;

gfx/src/windows/nsScreenWin.cpp

@@ -45,15 +45,19 @@ typedef BOOL (WINAPI *GetMonitorInfoProc)(HMONITOR inMon, LPMONITORINFO ioInfo);
 #endif
 
 
-nsScreenWin :: nsScreenWin ( HDC inContext, void* inScreen )
+nsScreenWin :: nsScreenWin ( void* inScreen )
-  : mContext(inContext), mScreen(inScreen), mHasMultiMonitorAPIs(PR_FALSE),
+  : mScreen(inScreen), mHasMultiMonitorAPIs(PR_FALSE),
       mGetMonitorInfoProc(nsnull)
 {
   NS_INIT_REFCNT();
 
-  NS_ASSERTION ( inContext, "Passing null device to nsScreenWin" );
+#ifdef DEBUG
-  NS_ASSERTION ( ::GetDeviceCaps(inContext, TECHNOLOGY) == DT_RASDISPLAY, "Not a display screen");
+  HDC hDCScreen = ::GetDC(nsnull);
-  
+  NS_ASSERTION(hDCScreen,"GetDC Failure");
+  NS_ASSERTION ( ::GetDeviceCaps(hDCScreen, TECHNOLOGY) == DT_RASDISPLAY, "Not a display screen");
+  ::ReleaseDC(nsnull,hDCScreen);
+#endif
+   
 #if _MSC_VER >= 1200
   // figure out if we can call the multiple monitor APIs that are only
   // available on Win98/2000.
@@ -101,11 +105,15 @@ nsScreenWin :: GetRect(PRInt32 *outLeft, PRInt32 *outTop, PRInt32 *outWidth, PRI
   }
 #endif
   if (!success) {
-    *outTop = *outLeft = 0;
+     HDC hDCScreen = ::GetDC(nsnull);
-    *outWidth = ::GetDeviceCaps(mContext, HORZRES);
+     NS_ASSERTION(hDCScreen,"GetDC Failure");
-    *outHeight = ::GetDeviceCaps(mContext, VERTRES);
+    
+     *outTop = *outLeft = 0;
+     *outWidth = ::GetDeviceCaps(hDCScreen, HORZRES);
+     *outHeight = ::GetDeviceCaps(hDCScreen, VERTRES); 
+     
+     ::ReleaseDC(nsnull, hDCScreen);
   }
-
   return NS_OK;
 
 } // GetRect
@@ -148,7 +156,12 @@ NS_IMETHODIMP
 nsScreenWin :: GetPixelDepth(PRInt32 *aPixelDepth)
 {
   //XXX not sure how to get this info for multiple monitors, this might be ok...
-  *aPixelDepth = ::GetDeviceCaps(mContext, BITSPIXEL);
+  HDC hDCScreen = ::GetDC(nsnull);
+  NS_ASSERTION(hDCScreen,"GetDC Failure");
+
+  *aPixelDepth = ::GetDeviceCaps(hDCScreen, BITSPIXEL);
+
+  ::ReleaseDC(nsnull, hDCScreen);
   return NS_OK;
 
 } // GetPixelDepth

gfx/src/windows/nsScreenWin.h

@@ -31,24 +31,19 @@
 class nsScreenWin : public nsIScreen
 {
 public:
-  nsScreenWin ( HDC inContext, void* inScreen );
+  nsScreenWin ( void* inScreen );
   ~nsScreenWin();
 
   NS_DECL_ISUPPORTS
   NS_DECL_NSISCREEN
 
 private:
-
-    // are we the primary screen? Needed so we can sub out the menubar if
-    // asked.
-  //PRBool IsPrimaryScreen ( ) const { return (mScreen == ::GetMainDevice()); }
   
     // function pointers for multi-monitor API system calls that we use. Not
     // valid unless |mHasMultiMonitorAPIs| is true
   PRBool mHasMultiMonitorAPIs;
   FARPROC mGetMonitorInfoProc ;
 
-  HDC mContext;                     // the dc that represents this screen
   void* mScreen;                    // a |HMONITOR|, can't use this type in header file though.
 };