seqdisp.c

本书介绍了在Microsoft Windows 98、Microsoft Windows NT 4.0和Windows NT 5.0下程序写作的方法。这些程序用C语言编写并使用原始的Windows A

/*-----------------------------------------
   SEQDISP.C -- Sequential Display of DIBs
                (c) Charles Petzold, 1998
  -----------------------------------------*/

#include <windows.h>
#include "resource.h"

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

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

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
{
     HACCEL   hAccel ;
     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 Sequential Display"),
                          WS_OVERLAPPEDWINDOW,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          CW_USEDEFAULT, CW_USEDEFAULT, 
                          NULL, NULL, hInstance, NULL) ;
     
     ShowWindow (hwnd, iCmdShow) ;
     UpdateWindow (hwnd) ;

     hAccel = LoadAccelerators (hInstance, szAppName) ;
     
     while (GetMessage (&msg, NULL, 0, 0))
     {
          if (!TranslateAccelerator (hwnd, hAccel, &msg))
          {
               TranslateMessage (&msg) ;
               DispatchMessage (&msg) ;
          }
     }
     return msg.wParam ;
}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
     static BITMAPINFO * pbmi ;
     static BYTE       * pBits ;
     static int          cxDib, cyDib, cBits ;
     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") ;
     BITMAPFILEHEADER    bmfh ;
     BOOL                bSuccess, bTopDown ;
     DWORD               dwBytesRead ;
     HANDLE              hFile ;
     HDC                 hdc ;
     HMENU               hMenu ;
     int                 iInfoSize, iBitsSize, iRowLength, y ;
     PAINTSTRUCT         ps ;
     
     switch (message)
     {
     case WM_CREATE:
          ofn.lStructSize       = sizeof (OPENFILENAME) ;
          ofn.hwndOwner         = hwnd ;
          ofn.hInstance         = NULL ;
          ofn.lpstrFilter       = szFilter ;
          ofn.lpstrCustomFilter = NULL ;
          ofn.nMaxCustFilter    = 0 ;
          ofn.nFilterIndex      = 0 ;
          ofn.lpstrFile         = szFileName ;
          ofn.nMaxFile          = MAX_PATH ;
          ofn.lpstrFileTitle    = szTitleName ;
          ofn.nMaxFileTitle     = MAX_PATH ;
          ofn.lpstrInitialDir   = NULL ;
          ofn.lpstrTitle        = NULL ;
          ofn.Flags             = 0 ;
          ofn.nFileOffset       = 0 ;
          ofn.nFileExtension    = 0 ;
          ofn.lpstrDefExt       = TEXT ("bmp") ;
          ofn.lCustData         = 0 ;
          ofn.lpfnHook          = NULL ;
          ofn.lpTemplateName    = NULL ;
          return 0 ;

     case WM_COMMAND:
          hMenu = GetMenu (hwnd) ; 

          switch (LOWORD (wParam))
          {
          case IDM_FILE_OPEN:
                    // Display File Open dialog

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

                    // Get rid of old DIB

               if (pbmi)
               {
                    free (pbmi) ;
                    pbmi = NULL ;
               }

               if (pBits)
               {
                    free (pBits) ;
                    pBits = NULL ;
               }

                    // Generate WM_PAINT message to erase background

               InvalidateRect (hwnd, NULL, TRUE) ;
               UpdateWindow (hwnd) ;

                    // Open the file

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

               if (hFile == INVALID_HANDLE_VALUE)
               {
                    MessageBox (hwnd, TEXT ("Cannot open file."), 
                                szAppName, MB_ICONWARNING | MB_OK) ;
                    return 0 ;
               }

                    // Read in the BITMAPFILEHEADER

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

               if (!bSuccess || dwBytesRead != sizeof (BITMAPFILEHEADER))
               {
                    MessageBox (hwnd, TEXT ("Cannot read file."), 
                                szAppName, MB_ICONWARNING | MB_OK) ;
                    CloseHandle (hFile) ;
                    return 0 ;
               }

                    // Check that it's a bitmap

               if (bmfh.bfType != * (WORD *) "BM")
               {
                    MessageBox (hwnd, TEXT ("File is not a bitmap."), 
                                szAppName, MB_ICONWARNING | MB_OK) ;
                    CloseHandle (hFile) ;
                    return 0 ;
               }

                    // Allocate memory for header and bits

               iInfoSize = bmfh.bfOffBits - sizeof (BITMAPFILEHEADER) ;
               iBitsSize = bmfh.bfSize - bmfh.bfOffBits ;

               pbmi  = malloc (iInfoSize) ;
               pBits = malloc (iBitsSize) ;

               if (pbmi == NULL || pBits == NULL)
               {
                    MessageBox (hwnd, TEXT ("Cannot allocate memory."), 
                                szAppName, MB_ICONWARNING | MB_OK) ;
                    if (pbmi) 
                         free (pbmi) ;
                    if (pBits) 
                         free (pBits) ;
                    CloseHandle (hFile) ;
                    return 0 ;
               }

                    // Read in the Information Header

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

               if (!bSuccess || (int) dwBytesRead != iInfoSize)
               {
                    MessageBox (hwnd, TEXT ("Cannot read file."), 
                                szAppName, MB_ICONWARNING | MB_OK) ;
                    if (pbmi) 
                         free (pbmi) ;
                    if (pBits) 
                         free (pBits) ;
                    CloseHandle (hFile) ;
                    return 0 ;
               }

                    // Get the DIB width and height

               bTopDown = FALSE ;

               if (pbmi->bmiHeader.biSize == sizeof (BITMAPCOREHEADER))
               {
                    cxDib = ((BITMAPCOREHEADER *) pbmi)->bcWidth ;
                    cyDib = ((BITMAPCOREHEADER *) pbmi)->bcHeight ;
                    cBits = ((BITMAPCOREHEADER *) pbmi)->bcBitCount ;
               }
               else
               {
                    if (pbmi->bmiHeader.biHeight < 0)
                         bTopDown = TRUE ;

                    cxDib =      pbmi->bmiHeader.biWidth ;
                    cyDib = abs (pbmi->bmiHeader.biHeight) ;
                    cBits =      pbmi->bmiHeader.biBitCount ;

                    if (pbmi->bmiHeader.biCompression != BI_RGB &&
                        pbmi->bmiHeader.biCompression != BI_BITFIELDS)
                    {
                         MessageBox (hwnd, TEXT ("File is compressed."), 
                                     szAppName, MB_ICONWARNING | MB_OK) ;
                         if (pbmi) 
                              free (pbmi) ;
                         if (pBits) 
                              free (pBits) ;
                         CloseHandle (hFile) ;
                         return 0 ;
                    }
               }
   
                    // Get the row length

               iRowLength = ((cxDib * cBits + 31) & ~31) >> 3 ;

                    // Read and display

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

               hdc = GetDC (hwnd) ;

               for (y = 0 ; y < cyDib ; y++)
               {
                    ReadFile (hFile, pBits + y * iRowLength, iRowLength,
                              &dwBytesRead, NULL) ;

                    SetDIBitsToDevice (hdc, 
                                       0,         // xDst
                                       0,         // yDst
                                       cxDib,     // cxSrc
                                       cyDib,     // cySrc
                                       0,         // xSrc
                                       0,         // ySrc
                                       bTopDown ? cyDib - y - 1 : y,
                                                  // first scan line
                                       1,         // number of scan lines
                                       pBits + y * iRowLength, 
                                       pbmi, 
                                       DIB_RGB_COLORS) ;
               }
               ReleaseDC (hwnd, hdc) ;
               CloseHandle (hFile) ;
               ShowCursor (FALSE) ;
               SetCursor (LoadCursor (NULL, IDC_ARROW)) ;
               return 0 ;
          }
          break ;

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

          if (pbmi && pBits)
               SetDIBitsToDevice (hdc, 
                                  0,         // xDst
                                  0,         // yDst
                                  cxDib,     // cxSrc
                                  cyDib,     // cySrc
                                  0,         // xSrc
                                  0,         // ySrc
                                  0,         // first scan line
                                  cyDib,     // number of scan lines
                                  pBits, 
                                  pbmi, 
                                  DIB_RGB_COLORS) ;
          EndPaint (hwnd, &ps) ;
          return 0 ;
     
     case WM_DESTROY:
          if (pbmi)
               free (pbmi) ;
          
          if (pBits)
               free (pBits) ;

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