#include <windows.h>

#define IDM_FILE_OPEN 40001

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;

TCHAR szAppName[] = TEXT ("DibSect") ;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
{
     HWND     hwnd ;
     MSG      msg ;
     WNDCLASS wndclass ;
     wndclass.style         = CS_HREDRAW | CS_VREDRAW ;
     wndclass.lpfnWndProc   = WndProc ;
     wndclass.cbClsExtra    = 0 ;
     wndclass.cbWndExtra    = 0 ;
     wndclass.hInstance     = hInstance ;
     wndclass.hIcon         = LoadIcon (NULL, IDI_APPLICATION) ;
     wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW) ;
     wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
     wndclass.lpszMenuName  = szAppName ;
     wndclass.lpszClassName = szAppName ;

     if (!RegisterClass (&wndclass))
     {
          MessageBox (NULL, TEXT ("This program requires Windows NT!"),
                      szAppName, MB_ICONERROR) ;
          return 0 ;
     }

     hwnd = CreateWindow (szAppName, TEXT ("DIB Section Display"),
                          WS_OVERLAPPEDWINDOW,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          NULL, NULL, hInstance, NULL) ;

     ShowWindow (hwnd, iCmdShow) ;
     UpdateWindow (hwnd) ;

     while (GetMessage (&msg, NULL, 0, 0))
     {
          TranslateMessage (&msg) ;
          DispatchMessage (&msg) ;

     }
     return msg.wParam ;
}
HBITMAP CreateDibSectionFromDibFile (PTSTR szFileName)
{
     BITMAPFILEHEADER bmfh ;
     BITMAPINFO     * pbmi ;
     BYTE           * pBits ;
     BOOL             bSuccess ;
     DWORD            dwInfoSize, dwBytesRead ;
     HANDLE           hFile ;
     HBITMAP          hBitmap = NULL;
          // Open the file: read access, prohibit write access

     hFile = CreateFile (szFileName, GENERIC_READ, FILE_SHARE_READ,
                         NULL, OPEN_EXISTING, 0, NULL) ;

     if (hFile == INVALID_HANDLE_VALUE)
          return NULL ;

          // Read in the BITMAPFILEHEADER

     bSuccess = ReadFile (hFile, &bmfh, sizeof (BITMAPFILEHEADER),
                          &dwBytesRead, NULL) ;

     if (!bSuccess || (dwBytesRead != sizeof (BITMAPFILEHEADER))
                   || (bmfh.bfType != * (WORD *) "BM"))
     {
          CloseHandle (hFile) ;
          return NULL ;
     }

          // Allocate memory for the BITMAPINFO structure & read it in

     dwInfoSize = bmfh.bfOffBits - sizeof (BITMAPFILEHEADER) ;

     pbmi = malloc (dwInfoSize) ;

     bSuccess = ReadFile (hFile, pbmi, dwInfoSize, &dwBytesRead, NULL) ;

     if (!bSuccess || (dwBytesRead != dwInfoSize))
     {
          free (pbmi) ;
          CloseHandle (hFile) ;
          return NULL ;
     }
          // Create the DIB Section

     hBitmap = CreateDIBSection (NULL, pbmi, DIB_RGB_COLORS, (VOID *)&pBits, NULL, 0) ;

     if (hBitmap == NULL)
     {
          free (pbmi) ;
          CloseHandle (hFile) ;
          return NULL ;
     }

          // Read in the bitmap bits

     ReadFile (hFile, pBits, bmfh.bfSize - bmfh.bfOffBits, &dwBytesRead, NULL) ;

     free (pbmi) ;
     CloseHandle (hFile) ;

     return hBitmap ;
}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
     static HBITMAP      hBitmap;
     static BOOL         fLeftButtonDown, fRightButtonDown ;
     static int          cxClient, cyClient, xMouse, yMouse ;
     static OPENFILENAME ofn ;
     static TCHAR        szFileName [MAX_PATH], szTitleName [MAX_PATH] ;
     static TCHAR        szFilter[] = TEXT ("Bitmap Files (*.BMP)\0*.bmp\0")
                                      TEXT ("All Files (*.*)\0*.*\0\0") ;
     BITMAP              bitmap ;
     HDC                 hdc, hdcMem ;
     PAINTSTRUCT         ps ;

     switch (message)
     {
     case WM_CREATE:
          ZeroMemory(&ofn, sizeof(OPENFILENAME));
          ofn.lStructSize       = sizeof (OPENFILENAME) ;
          ofn.hwndOwner         = hwnd ;
          ofn.lpstrFilter       = szFilter ;
          ofn.lpstrFile         = szFileName ;
          ofn.nMaxFile          = MAX_PATH ;
          ofn.lpstrFileTitle    = szTitleName ;
          ofn.nMaxFileTitle     = MAX_PATH ;
          ofn.lpstrDefExt       = TEXT ("bmp") ;

          return 0 ;

     case WM_SIZE:
          cxClient = LOWORD (lParam) ;
          cyClient = HIWORD (lParam) ;
          return 0 ;

     case WM_COMMAND:
          switch (LOWORD (wParam))
          {
          case IDM_FILE_OPEN:

                    // Show the File Open dialog box

               if (!GetOpenFileName (&ofn))
                    return 0 ;

                    // If there's an existing bitmap, delete it

               if (hBitmap)
               {
                    DeleteObject (hBitmap);
                    hBitmap = NULL ;
               }
                    // Create the DIB Section from the DIB file

               SetCursor (LoadCursor (NULL, IDC_WAIT)) ;
               ShowCursor (TRUE) ;

               hBitmap = CreateDibSectionFromDibFile (szFileName) ;
               ShowCursor (FALSE) ;
               SetCursor (LoadCursor (NULL, IDC_ARROW)) ;

                    // Invalidate the client area for later update

               InvalidateRect (hwnd, NULL, TRUE) ;

               if (hBitmap == NULL)
               {
                    MessageBox (hwnd, TEXT ("Cannot load DIB file"),
                                szAppName, MB_OK | MB_ICONEXCLAMATION) ;
               }
               return 0 ;
          }
          break ;

    case WM_LBUTTONDOWN:
          if (!fRightButtonDown)
               SetCapture (hwnd) ;

          xMouse = LOWORD (lParam) ;
          yMouse = HIWORD (lParam) ;
          fLeftButtonDown = TRUE ;
          return 0 ;

     case WM_LBUTTONUP:
          if (fLeftButtonDown)
               SetCapture (NULL) ;

          fLeftButtonDown = FALSE ;
          return 0 ;

     case WM_RBUTTONDOWN:
          if (!fLeftButtonDown)
               SetCapture (hwnd) ;

          xMouse = LOWORD (lParam) ;
          yMouse = HIWORD (lParam) ;
          fRightButtonDown = TRUE ;
          return 0 ;

     case WM_RBUTTONUP:
          if (fRightButtonDown)
               SetCapture (NULL) ;

          fRightButtonDown = FALSE ;
          return 0 ;

     case WM_MOUSEMOVE:
          if (!fLeftButtonDown && !fRightButtonDown)
               return 0 ;

          hdc = GetDC (hwnd) ;

          SelectObject (hdcMem, hBitmap);
          SelectObject (hdc, hBitmap);

          SelectObject (hdc,
               GetStockObject (fLeftButtonDown ? BLACK_PEN : WHITE_PEN)) ;

          SelectObject (hdcMem,
               GetStockObject (fLeftButtonDown ? BLACK_PEN : WHITE_PEN)) ;

          MoveToEx (hdc,    xMouse, yMouse, NULL) ;
          MoveToEx (hdcMem, xMouse, yMouse, NULL) ;

          xMouse = (short) LOWORD (lParam) ;
          yMouse = (short) HIWORD (lParam) ;

          LineTo (hdc,    xMouse, yMouse) ;
          LineTo (hdcMem, xMouse, yMouse) ;

          ReleaseDC (hwnd, hdc) ;
          return 0 ;

     case WM_PAINT:
          hdc = BeginPaint (hwnd, &ps) ;

          if (hBitmap)
          {
               GetObject (hBitmap, sizeof (BITMAP), &bitmap) ;

               hdcMem = CreateCompatibleDC (hdc) ;
               SelectObject (hdcMem, hBitmap) ;

               BitBlt (hdc,    0, 0, bitmap.bmWidth, bitmap.bmHeight,
                       hdcMem, 0, 0, SRCCOPY) ;

               DeleteDC (hdcMem) ;
          }

          EndPaint (hwnd, &ps) ;
          return 0 ;

     case WM_DESTROY:
          if (hBitmap)
               DeleteObject (hBitmap) ;

          PostQuitMessage (0) ;
          return 0 ;
     }
     return DefWindowProc (hwnd, message, wParam, lParam) ;
}

#define IDM_FILE_OPEN 40001

DIBSECT MENU DISCARDABLE
BEGIN
    POPUP "&File"
    BEGIN
        MENUITEM "&Open", IDM_FILE_OPEN
    END
END

BitBlt (ps.hdc, ps.rcPaint.left, ps.rcPaint.top, ps.rcPaint.right - ps.rcPaint.left,
ps.rcPaint.bottom - ps.rcPaint.top, hdcMem, ps.rcPaint.left, ps.rcPaint.top, SRCCOPY) ;