emfview.c

Windows Programming source code

/*----------------------------------------
   EMFVIEW.C -- View Enhanced Metafiles
                (c) Charles Petzold, 1998
  ----------------------------------------*/

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

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

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

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 ("Enhanced Metafile Viewer"),
                          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 ;
}

HPALETTE CreatePaletteFromMetaFile (HENHMETAFILE hemf)
{
     HPALETTE     hPalette ;
     int          iNum ;
     LOGPALETTE * plp ;

     if (!hemf)
          return NULL ;

     if (0 == (iNum = GetEnhMetaFilePaletteEntries (hemf, 0, NULL)))
          return NULL ;

     plp = malloc (sizeof (LOGPALETTE) + (iNum - 1) * sizeof (PALETTEENTRY)) ;

     plp->palVersion    = 0x0300 ;
     plp->palNumEntries = iNum ;

     GetEnhMetaFilePaletteEntries (hemf, iNum, plp->palPalEntry) ;
     
     hPalette = CreatePalette (plp) ;

     free (plp) ;

     return hPalette ;
}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
     static DOCINFO      di = { sizeof (DOCINFO), TEXT ("EmfView: Printing") } ;
     static HENHMETAFILE hemf ;
     static OPENFILENAME ofn ;
     static PRINTDLG     printdlg = { sizeof (PRINTDLG) } ;
     static TCHAR        szFileName [MAX_PATH], szTitleName [MAX_PATH] ;
     static TCHAR        szFilter[] = 
                               TEXT ("Enhanced Metafiles (*.EMF)\0*.emf\0")
                               TEXT ("All Files (*.*)\0*.*\0\0") ;
     BOOL                bSuccess ;
     ENHMETAHEADER       header ;
     HDC                 hdc, hdcPrn ;
     HENHMETAFILE        hemfCopy ;
     HMENU               hMenu ;
     HPALETTE            hPalette ;
     int                 i, iLength, iEnable ;
     PAINTSTRUCT         ps ;
     RECT                rect ;
     PTSTR               pBuffer ;

     switch (message)
     {
     case WM_CREATE:
               // Initialize OPENFILENAME structure
     
          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 ("emf") ;
          ofn.lCustData         = 0 ;
          ofn.lpfnHook          = NULL ;
          ofn.lpTemplateName    = NULL ;
          return 0 ;

     case WM_INITMENUPOPUP:
          hMenu = GetMenu (hwnd) ;

          iEnable = hemf ? MF_ENABLED : MF_GRAYED ;

          EnableMenuItem (hMenu, IDM_FILE_SAVE_AS,    iEnable) ;
          EnableMenuItem (hMenu, IDM_FILE_PRINT,      iEnable) ;
          EnableMenuItem (hMenu, IDM_FILE_PROPERTIES, iEnable) ;
          EnableMenuItem (hMenu, IDM_EDIT_CUT,        iEnable) ;
          EnableMenuItem (hMenu, IDM_EDIT_COPY,       iEnable) ;
          EnableMenuItem (hMenu, IDM_EDIT_DELETE,     iEnable) ;

          EnableMenuItem (hMenu, IDM_EDIT_PASTE,
               IsClipboardFormatAvailable (CF_ENHMETAFILE) ?
                    MF_ENABLED : MF_GRAYED) ;
          return 0 ;

     case WM_COMMAND:
          switch (LOWORD (wParam))
          {
          case IDM_FILE_OPEN:
                    // Show the File Open dialog box

               ofn.Flags = 0 ;
     
               if (!GetOpenFileName (&ofn))
                    return 0 ;
               
                    // If there's an existing EMF, get rid of it.

               if (hemf)
               {
                    DeleteEnhMetaFile (hemf) ;
                    hemf = NULL ;
               }
                    // Load the EMF into memory

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

               hemf = GetEnhMetaFile (szFileName) ;

               ShowCursor (FALSE) ;
               SetCursor (LoadCursor (NULL, IDC_ARROW)) ;

                    // Invalidate the client area for later update

               InvalidateRect (hwnd, NULL, TRUE) ;

               if (hemf == NULL)
               {
                    MessageBox (hwnd, TEXT ("Cannot load metafile"), 
                                szAppName, MB_ICONEXCLAMATION | MB_OK) ;
               }
               return 0 ;

          case IDM_FILE_SAVE_AS:
               if (!hemf)
                    return 0 ;

                    // Show the File Save dialog box

               ofn.Flags = OFN_OVERWRITEPROMPT ;
     
               if (!GetSaveFileName (&ofn))
                    return 0 ;
               
                    // Save the EMF to disk file

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

               hemfCopy = CopyEnhMetaFile (hemf, szFileName) ;

               ShowCursor (FALSE) ;
               SetCursor (LoadCursor (NULL, IDC_ARROW)) ;

               if (hemfCopy)
               {
                    DeleteEnhMetaFile (hemf) ;
                    hemf = hemfCopy ;
               }
               else
                    MessageBox (hwnd, TEXT ("Cannot save metafile"), 
                                szAppName, MB_ICONEXCLAMATION | MB_OK) ;
               return 0 ;

          case IDM_FILE_PRINT:
                    // Show the Print dialog box and get printer DC
	
	          printdlg.Flags = PD_RETURNDC | PD_NOPAGENUMS | PD_NOSELECTION ;

	          if (!PrintDlg (&printdlg))
		          return 0 ;
               
               if (NULL == (hdcPrn = printdlg.hDC)) 
               {
                    MessageBox (hwnd, TEXT ("Cannot obtain printer DC"),
                                szAppName, MB_ICONEXCLAMATION | MB_OK) ;
                    return 0 ;
               }
                    // Get size of printable area of page

               rect.left   = 0 ;
               rect.right  = GetDeviceCaps (hdcPrn, HORZRES) ;
               rect.top    = 0 ;
               rect.bottom = GetDeviceCaps (hdcPrn, VERTRES) ;

               bSuccess = FALSE ;

                    // Play the EMF to the printer

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

               if ((StartDoc (hdcPrn, &di) > 0) && (StartPage (hdcPrn) > 0))
               {
                    PlayEnhMetaFile (hdcPrn, hemf, &rect) ;
                    
                    if (EndPage (hdcPrn) > 0)
                    {
                         bSuccess = TRUE ;
                         EndDoc (hdcPrn) ;
                    }
               }
               ShowCursor (FALSE) ;
               SetCursor (LoadCursor (NULL, IDC_ARROW)) ;

               DeleteDC (hdcPrn) ;

               if (!bSuccess)
                    MessageBox (hwnd, TEXT ("Could not print metafile"),
                                szAppName, MB_ICONEXCLAMATION | MB_OK) ;
               return 0 ;

          case IDM_FILE_PROPERTIES:
               if (!hemf)
                    return 0 ;

               iLength = GetEnhMetaFileDescription (hemf, 0, NULL) ;
               pBuffer = malloc ((iLength + 256) * sizeof (TCHAR)) ;

               GetEnhMetaFileHeader (hemf, sizeof (ENHMETAHEADER), &header) ;

                    // Format header file information 

               i  = wsprintf (pBuffer, 
                              TEXT ("Bounds = (%i, %i) to (%i, %i) pixels\n"),
                              header.rclBounds.left, header.rclBounds.top,
                              header.rclBounds.right, header.rclBounds.bottom) ;

               i += wsprintf (pBuffer + i, 
                              TEXT ("Frame = (%i, %i) to (%i, %i) mms\n"),
                              header.rclFrame.left, header.rclFrame.top,
                              header.rclFrame.right, header.rclFrame.bottom) ;

               i += wsprintf (pBuffer + i,
                              TEXT ("Resolution = (%i, %i) pixels")
                              TEXT (" = (%i, %i) mms\n"),
                              header.szlDevice.cx, header.szlDevice.cy,
                              header.szlMillimeters.cx, 
                              header.szlMillimeters.cy) ;

               i += wsprintf (pBuffer + i,
                              TEXT ("Size = %i, Records = %i, ")
                              TEXT ("Handles = %i, Palette entries = %i\n"),
                              header.nBytes, header.nRecords,
                              header.nHandles, header.nPalEntries) ;

                    // Include the metafile description, if present

               if (iLength)
               {
                    i += wsprintf (pBuffer + i, TEXT ("Description = ")) ;
                    GetEnhMetaFileDescription (hemf, iLength, pBuffer + i) ;
                    pBuffer [lstrlen (pBuffer)] = '\t' ;
               }

               MessageBox (hwnd, pBuffer, TEXT ("Metafile Properties"), MB_OK) ;
               free (pBuffer) ;                              
               return 0 ;

          case IDM_EDIT_COPY:
          case IDM_EDIT_CUT:
               if (!hemf)
                    return 0 ;

                    // Transfer metafile copy to the clipboard

               hemfCopy = CopyEnhMetaFile (hemf, NULL) ;

               OpenClipboard (hwnd) ;
               EmptyClipboard () ;
               SetClipboardData (CF_ENHMETAFILE, hemfCopy) ;
               CloseClipboard () ;

               if (LOWORD (wParam) == IDM_EDIT_COPY)
                    return 0 ;
                                        // fall through if IDM_EDIT_CUT 
          case IDM_EDIT_DELETE:
               if (hemf)
               {
                    DeleteEnhMetaFile (hemf) ;
                    hemf = NULL ;
                    InvalidateRect (hwnd, NULL, TRUE) ;
               }
               return 0 ;

          case IDM_EDIT_PASTE:
               OpenClipboard (hwnd) ;
               hemfCopy = GetClipboardData (CF_ENHMETAFILE) ;
               CloseClipboard () ;

               if (hemfCopy && hemf)
               {
                    DeleteEnhMetaFile (hemf) ;
                    hemf = NULL ;
               }

               hemf = CopyEnhMetaFile (hemfCopy, NULL) ;
               InvalidateRect (hwnd, NULL, TRUE) ;
               return 0 ;

          case IDM_APP_ABOUT:
               MessageBox (hwnd, TEXT ("Enhanced Metafile Viewer\n")
                                 TEXT ("(c) Charles Petzold, 1998"),
                           szAppName, MB_OK) ;
               return 0 ;

          case IDM_APP_EXIT:
               SendMessage (hwnd, WM_CLOSE, 0, 0L) ;
               return 0 ;
          }
          break ;
         
     case WM_PAINT:
          hdc = BeginPaint (hwnd, &ps) ;

          if (hemf)
          {
               if (hPalette = CreatePaletteFromMetaFile (hemf))
               {
                    SelectPalette (hdc, hPalette, FALSE) ;
                    RealizePalette (hdc) ;
               }
               GetClientRect (hwnd, &rect) ;
               PlayEnhMetaFile (hdc, hemf, &rect) ;

               if (hPalette)
                    DeleteObject (hPalette) ;
          }
          EndPaint (hwnd, &ps) ;
          return 0 ;

     case WM_QUERYNEWPALETTE:
          if (!hemf || !(hPalette = CreatePaletteFromMetaFile (hemf)))
               return FALSE ;

          hdc = GetDC (hwnd) ;
          SelectPalette (hdc, hPalette, FALSE) ;
          RealizePalette (hdc) ;
          InvalidateRect (hwnd, NULL, FALSE) ;

          DeleteObject (hPalette) ;
          ReleaseDC (hwnd, hdc) ;
          return TRUE ;

     case WM_PALETTECHANGED:
          if ((HWND) wParam == hwnd)
               break ;

          if (!hemf || !(hPalette = CreatePaletteFromMetaFile (hemf)))
               break ;

          hdc = GetDC (hwnd) ;
          SelectPalette (hdc, hPalette, FALSE) ;
          RealizePalette (hdc) ;
          UpdateColors (hdc) ;

          DeleteObject (hPalette) ;
          ReleaseDC (hwnd, hdc) ;
          break ;
          
     case WM_DESTROY:
          if (hemf)
               DeleteEnhMetaFile (hemf) ;

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