屏幕保护程序使用EnumDisplayMonitors第二个监视器上绘制黑色rectanlge

我想下面的代码，但我得到我的第二个监视器上没有，但应该是我的绘画图像的黑色矩形（使用GDI）。有没有人听说过这个问题吗？我做第二个监视器上（位图或文字）任何绘图呈现为一个黑色的矩形。谢谢！

LRESULT WINAPI ScreenSaverProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam)  

{

   static UINT         uTimer;   // timer identifier



   // Handles screen saver messages  

   switch(message)  

   { 

      // <snip>

      case WM_PAINT:   //  Sent when the system or another application makes a request to paint a portion of an application's window (e.g., UpdateWindow/RedrawWindow)

      {

         PAINTSTRUCT lpPaint = {0};

         HDC hdc = BeginPaint(hwnd, &lpPaint );

            EnumDisplayMonitors(hdc, NULL, MonitorNumProcPaint, 0);  // For every monitor attached, call the passed in function

         EndPaint(hwnd, &lpPaint);

         return true;

      }

      // <snip>

   }

}

 

BOOL CALLBACK MonitorNumProcPaint(HMONITOR hMonitor, HDC hdc, LPRECT lprcMonitor, LPARAM data)

{

   // If the coordinates of the top left corner are 0,0, then we're rendering on the primary monitor, otherwise we're not.

   if (lprcMonitor->left == 0 && lprcMonitor->top == 0)

      return (PaintPrimaryDisplay(hMonitor, hdc, lprcMonitor, data));

   else

      return (PaintNonPrimaryDisplay(hMonitor, hdc, lprcMonitor, data));

}

 

bool PaintNonPrimaryDisplay(HMONITOR hMonitor, HDC hdc, LPRECT lprcMonitor, LPARAM data)

{

   Gdiplus::Graphics * pGraphics = Gdiplus::Graphics::FromHDC(hdc);

 

   if (gpBitmapMotivation2)

   {

      pGraphics->DrawImage(gpBitmapMotivation2, lprcMonitor->left, lprcMonitor->top, lprcMonitor->right - lprcMonitor->left, lprcMonitor->bottom - lprcMonitor->top);

   }

 

   int sizeX = (int) ceil( (lprcMonitor->right - lprcMonitor->left) * SS_SCREEN_PERCENTAGE);

   int sizeY = (int) ceil( (lprcMonitor->bottom- lprcMonitor->top)  * SS_SCREEN_PERCENTAGE);

   DrawMyText(lprcMonitor, sizeX, sizeY, pGraphics, "MyText"); // This custom function sets up the font, etc and renders the text.



   BitBlt(hdc, lprcMonitor->left, lprcMonitor->top, lprcMonitor->right - lprcMonitor->left, lprcMonitor->bottom - lprcMonitor->top, hdc, lprcMonitor->left, lprcMonitor->top, SRCCOPY);

 

   return true;

}