/*******************************************************************************
 * pvbitmap.cpp
 *
 * Provides an API for bitmap manipulation.
 *
 * This file is derived from Microsoft sample source and is used by permission.
 *
 * ---------------------------------------------------------------------------
 * Persistence of Vision Ray Tracer ('POV-Ray') version 3.7.
 * Copyright 1991-2013 Persistence of Vision Raytracer Pty. Ltd.
 *
 * POV-Ray is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * POV-Ray is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * ---------------------------------------------------------------------------
 * POV-Ray is based on the popular DKB raytracer version 2.12.
 * DKBTrace was originally written by David K. Buck.
 * DKBTrace Ver 2.0-2.12 were written by David K. Buck & Aaron A. Collins.
 * ---------------------------------------------------------------------------
 * $File: //depot/public/povray/3.x/windows/pvbitmap.cpp $
 * $Revision: #1 $
 * $Change: 6069 $
 * $DateTime: 2013/11/06 11:59:40 $
 * $Author: chrisc $
 *******************************************************************************/

#define POVWIN_FILE
#define _WIN32_IE COMMONCTRL_VERSION

#include <windows.h>
#include <string.h>
#include "pvengine.h"
#include "pvbitmap.h"
#include "pvdisplay.h"

// this must be the last file included
#include "syspovdebug.h"

#define DIB_HEADER_MARKER   ((WORD) ('M' << 8) | 'B')

/*********************************************************************
 *
 * Local Function Prototypes
 *
 *********************************************************************/

namespace povwin
{

HANDLE ReadDIBFile(int);
bool MyRead(int, LPSTR, DWORD);
bool SaveDIBFile(void);
bool WriteDIB(LPSTR, HANDLE);
DWORD PASCAL MyWrite(int, VOID *, DWORD);

extern int              render_bitmap_depth ;
extern HPALETTE         hPalBitmap ;

/*************************************************************************
 *
 * CreateDIB()
 *
 * Parameters:
 *
 * DWORD dwWidth    - Width for new bitmap, in pixels
 * DWORD dwHeight   - Height for new bitmap 
 * WORD  wBitCount  - Bit Count for new DIB (1, 4, 8, or 24)
 *
 * Return Value:
 *
 * HDIB             - Handle to new DIB
 *
 * Description:
 *
 * This function allocates memory for and initializes a new DIB by
 * filling in the BITMAPINFOHEADER, allocating memory for the color
 * table, and allocating memory for the bitmap bits.  As with all
 * HDIBs, the header, colortable and bits are all in one contiguous
 * memory block.  This function is similar to the CreateBitmap() 
 * Windows API.
 *
 * The colortable and bitmap bits are left uninitialized (zeroed) in the
 * returned HDIB.
 *
 *
 * History:   Date      Author              Reason
 *            3/20/92   Mark Bader          Created
 *
 ************************************************************************/

HDIB CreateDIB(DWORD dwWidth, DWORD dwHeight, WORD wBitCount)
{
   BITMAPINFOHEADER bi;         // bitmap header
   LPBITMAPINFOHEADER lpbi;     // pointer to BITMAPINFOHEADER
   DWORD dwLen;                 // size of memory block
   HDIB hDIB;
   DWORD dwBytesPerLine;        // Number of bytes per scanline


   // Make sure bits per pixel is valid
   if (wBitCount <= 1)
      wBitCount = 1;
   else if (wBitCount <= 4)
      wBitCount = 4;
   else if (wBitCount <= 8)
      wBitCount = 8;
   else if (wBitCount <= 24)
      wBitCount = 24;
   else
      wBitCount = 4;  // set default value to 4 if parameter is bogus

   // initialize BITMAPINFOHEADER
   bi.biSize = sizeof(BITMAPINFOHEADER);
   bi.biWidth = dwWidth;         // fill in width from parameter
   bi.biHeight = dwHeight;       // fill in height from parameter
   bi.biPlanes = 1;              // must be 1
   bi.biBitCount = wBitCount;    // from parameter
   bi.biCompression = BI_RGB;    
   bi.biSizeImage = 0;           // 0's here mean "default"
   bi.biXPelsPerMeter = 0;
   bi.biYPelsPerMeter = 0;
   bi.biClrUsed = 0;
   bi.biClrImportant = 0;

   // calculate size of memory block required to store the DIB.  This
   // block should be big enough to hold the BITMAPINFOHEADER, the color
   // table, and the bits

   dwBytesPerLine = WIDTHBYTES(wBitCount * dwWidth);
   dwLen = bi.biSize + PaletteSize((LPSTR)&bi) + (dwBytesPerLine * dwHeight);

   // alloc memory block to store our bitmap
   hDIB = GlobalAlloc(GHND, dwLen);

   // major bummer if we couldn't get memory block
   if (!hDIB)
   {
      return NULL;
   }

   // lock memory and get pointer to it
   lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDIB);

   // use our bitmap info structure to fill in first part of
   // our DIB with the BITMAPINFOHEADER
   *lpbi = bi;

   // Since we don't know what the colortable and bits should contain,
   // just leave these blank.  Unlock the DIB and return the HDIB.

   GlobalUnlock(hDIB);

   /* return handle to the DIB */
   return hDIB;
}



/*************************************************************************
 *
 * FindDIBBits()
 *
 * Parameter:
 *
 * LPSTR lpDIB      - pointer to packed-DIB memory block
 *
 * Return Value:
 *
 * LPSTR            - pointer to the DIB bits
 *
 * Description:
 *
 * This function calculates the address of the DIB's bits and returns a
 * pointer to the DIB bits.
 *
 * History:   Date      Author              Reason
 *            6/01/91   Garrett McAuliffe   Created
 *            9/15/91   Patrick Schreiber   Added header and comments
 *
 ************************************************************************/


LPSTR FindDIBBits(LPSTR lpDIB)
{
   return (lpDIB + *(LPDWORD)lpDIB + PaletteSize(lpDIB));
}


/*************************************************************************
 *
 * DIBWidth()
 *
 * Parameter:
 *
 * LPSTR lpDIB      - pointer to packed-DIB memory block
 *
 * Return Value:
 *
 * DWORD            - width of the DIB
 *
 * Description:
 *
 * This function gets the width of the DIB from the BITMAPINFOHEADER
 * width field if it is a Windows 3.0-style DIB or from the BITMAPCOREHEADER
 * width field if it is an OS/2-style DIB.
 *
 * History:   Date      Author               Reason
 *            6/01/91   Garrett McAuliffe    Created
 *            9/15/91   Patrick Schreiber    Added header and comments
 *
 ************************************************************************/


DWORD DIBWidth(LPSTR lpDIB)
{
   LPBITMAPINFOHEADER lpbmi;  // pointer to a Win 3.0-style DIB
   LPBITMAPCOREHEADER lpbmc;  // pointer to an OS/2-style DIB

   /* point to the header (whether Win 3.0 and OS/2) */

   lpbmi = (LPBITMAPINFOHEADER)lpDIB;
   lpbmc = (LPBITMAPCOREHEADER)lpDIB;

   /* return the DIB width if it is a Win 3.0 DIB */
   if (lpbmi->biSize == sizeof(BITMAPINFOHEADER))
      return lpbmi->biWidth;
   else  /* it is an OS/2 DIB, so return its width */
      return (DWORD)lpbmc->bcWidth;
}


/*************************************************************************
 *
 * DIBHeight()
 *
 * Parameter:
 *
 * LPSTR lpDIB      - pointer to packed-DIB memory block
 *
 * Return Value:
 *
 * DWORD            - height of the DIB
 *
 * Description:
 *
 * This function gets the height of the DIB from the BITMAPINFOHEADER
 * height field if it is a Windows 3.0-style DIB or from the BITMAPCOREHEADER
 * height field if it is an OS/2-style DIB.
 *
 * History:   Date      Author               Reason
 *            6/01/91   Garrett McAuliffe    Created
 *            9/15/91   Patrick Schreiber    Added header and comments
 *
 ************************************************************************/


DWORD DIBHeight(LPSTR lpDIB)
{
   LPBITMAPINFOHEADER lpbmi;  // pointer to a Win 3.0-style DIB
   LPBITMAPCOREHEADER lpbmc;  // pointer to an OS/2-style DIB

   /* point to the header (whether OS/2 or Win 3.0 */

   lpbmi = (LPBITMAPINFOHEADER)lpDIB;
   lpbmc = (LPBITMAPCOREHEADER)lpDIB;

   /* return the DIB height if it is a Win 3.0 DIB */
   if (lpbmi->biSize == sizeof(BITMAPINFOHEADER))
      return lpbmi->biHeight;
   else  /* it is an OS/2 DIB, so return its height */
      return (DWORD)lpbmc->bcHeight;
}


/*************************************************************************
 *
 * PaletteSize()
 *
 * Parameter:
 *
 * LPSTR lpDIB      - pointer to packed-DIB memory block
 *
 * Return Value:
 *
 * WORD             - size of the color palette of the DIB
 *
 * Description:
 *
 * This function gets the size required to store the DIB's palette by
 * multiplying the number of colors by the size of an RGBQUAD (for a
 * Windows 3.0-style DIB) or by the size of an RGBTRIPLE (for an OS/2-
 * style DIB).
 *
 * History:   Date      Author             Reason
 *            6/01/91   Garrett McAuliffe  Created
 *            9/15/91   Patrick Schreiber  Added header and comments
 *
 ************************************************************************/


WORD PaletteSize(LPSTR lpDIB)
{
   /* calculate the size required by the palette */
   if (IS_WIN30_DIB (lpDIB))
      return (DIBNumColors(lpDIB) * sizeof(RGBQUAD));
   else
      return (DIBNumColors(lpDIB) * sizeof(RGBTRIPLE));
}


/*************************************************************************
 *
 * DIBNumColors()
 *
 * Parameter:
 *
 * LPSTR lpDIB      - pointer to packed-DIB memory block
 *
 * Return Value:
 *
 * WORD             - number of colors in the color table
 *
 * Description:
 *
 * This function calculates the number of colors in the DIB's color table
 * by finding the bits per pixel for the DIB (whether Win3.0 or OS/2-style
 * DIB). If bits per pixel is 1: colors=2, if 4: colors=16, if 8: colors=256,
 * if 24, no colors in color table.
 *
 * History:   Date      Author               Reason
 *            6/01/91   Garrett McAuliffe    Created
 *            9/15/91   Patrick Schreiber    Added header and comments
 *
 ************************************************************************/


WORD DIBNumColors(LPSTR lpDIB)
{
   WORD wBitCount;  // DIB bit count

   /*  If this is a Windows-style DIB, the number of colors in the
    *  color table can be less than the number of bits per pixel
    *  allows for (i.e. lpbi->biClrUsed can be set to some value).
    *  If this is the case, return the appropriate value.
    */

   if (IS_WIN30_DIB(lpDIB))
   {
      DWORD dwClrUsed;

      dwClrUsed = ((LPBITMAPINFOHEADER)lpDIB)->biClrUsed;
      if (dwClrUsed)
     return (WORD)dwClrUsed;
   }

   /*  Calculate the number of colors in the color table based on
    *  the number of bits per pixel for the DIB.
    */
   if (IS_WIN30_DIB(lpDIB))
      wBitCount = ((LPBITMAPINFOHEADER)lpDIB)->biBitCount;
   else
      wBitCount = ((LPBITMAPCOREHEADER)lpDIB)->bcBitCount;

   /* return number of colors based on bits per pixel */
   switch (wBitCount)
      {
   case 1:
      return 2;

   case 4:
      return 16;

   case 8:
      return 256;

   default:
      return 0;
      }
}


/*************************************************************************
 *
 * CreateDIBPalette()
 *
 * Parameter:
 *
 * HDIB hDIB        - specifies the DIB
 *
 * Return Value:
 *
 * HPALETTE         - specifies the palette
 *
 * Description:
 *
 * This function creates a palette from a DIB by allocating memory for the
 * logical palette, reading and storing the colors from the DIB's color table
 * into the logical palette, creating a palette from this logical palette,
 * and then returning the palette's handle. This allows the DIB to be
 * displayed using the best possible colors (important for DIBs with 256 or
 * more colors).
 *
 * History:   Date      Author               Reason
 *            6/01/91   Garrett McAuliffe    Created
 *            9/15/91   Patrick Schreiber    Added header and comments
 *
 ************************************************************************/


HPALETTE CreateDIBPalette(HDIB hDIB)
{
   LPLOGPALETTE lpPal;      // pointer to a logical palette
   HANDLE hLogPal;          // handle to a logical palette
   HPALETTE hPal = NULL;    // handle to a palette
   int i, wNumColors;       // loop index, number of colors in color table
   LPSTR lpbi;              // pointer to packed-DIB
   LPBITMAPINFO lpbmi;      // pointer to BITMAPINFO structure (Win3.0)
   LPBITMAPCOREINFO lpbmc;  // pointer to BITMAPCOREINFO structure (OS/2)
   bool bWinStyleDIB;       // flag which signifies whether this is a Win3.0 DIB

   /* if handle to DIB is invalid, return NULL */

   if (!hDIB)
      return NULL;

   /* lock DIB memory block and get a pointer to it */
   lpbi = (LPSTR)GlobalLock(hDIB);

   /* get pointer to BITMAPINFO (Win 3.0) */
   lpbmi = (LPBITMAPINFO)lpbi;

   /* get pointer to BITMAPCOREINFO (OS/2 1.x) */
   lpbmc = (LPBITMAPCOREINFO)lpbi;

   /* get the number of colors in the DIB */
   wNumColors = DIBNumColors(lpbi);

   /* is this a Win 3.0 DIB? */
   bWinStyleDIB = IS_WIN30_DIB(lpbi);
   if (wNumColors)
   {
      /* allocate memory block for logical palette */
      hLogPal = GlobalAlloc(GHND, sizeof(LOGPALETTE) + sizeof(PALETTEENTRY) *
                wNumColors);

      /* if not enough memory, clean up and return NULL */
      if (!hLogPal)
      {
     GlobalUnlock(hDIB);
     return NULL;
      }

      /* lock memory block and get pointer to it */
      lpPal = (LPLOGPALETTE)GlobalLock(hLogPal);

      /* set version and number of palette entries */
      lpPal->palVersion = PALVERSION;
      lpPal->palNumEntries = wNumColors;

      /*  store RGB triples (if Win 3.0 DIB) or RGB quads (if OS/2 DIB)
       *  into palette
       */
      for (i = 0; i < wNumColors; i++)
      {
     if (bWinStyleDIB)
     {
        lpPal->palPalEntry[i].peRed = lpbmi->bmiColors[i].rgbRed;
        lpPal->palPalEntry[i].peGreen = lpbmi->bmiColors[i].rgbGreen;
        lpPal->palPalEntry[i].peBlue = lpbmi->bmiColors[i].rgbBlue;
        lpPal->palPalEntry[i].peFlags = 0;
     }
     else
     {
        lpPal->palPalEntry[i].peRed = lpbmc->bmciColors[i].rgbtRed;
        lpPal->palPalEntry[i].peGreen = lpbmc->bmciColors[i].rgbtGreen;
        lpPal->palPalEntry[i].peBlue = lpbmc->bmciColors[i].rgbtBlue;
        lpPal->palPalEntry[i].peFlags = 0;
     }
      }

      /* create the palette and get handle to it */
      hPal = CreatePalette(lpPal);

      /* if error getting handle to palette, clean up and return NULL */
      if (!hPal)
      {
     GlobalUnlock(hLogPal);
     GlobalFree(hLogPal);
     return NULL;
      }
   }

   /* clean up */
   GlobalUnlock(hLogPal);
   GlobalFree(hLogPal);
   GlobalUnlock(hDIB);

   /* return handle to DIB's palette */
   return hPal;
}

/*************************************************************************
 *
 * DIBToBitmap()
 *
 * Parameters:
 *
 * HDIB hDIB        - specifies the DIB to convert
 *
 * HPALETTE hPal    - specifies the palette to use with the bitmap
 *
 * Return Value:
 *
 * HBITMAP          - identifies the device-dependent bitmap
 *
 * Description:
 *
 * This function creates a bitmap from a DIB using the specified palette.
 * If no palette is specified, default is used.
 *
 * NOTE:
 *
 * The bitmap returned from this funciton is always a bitmap compatible
 * with the screen (e.g. same bits/pixel and color planes) rather than
 * a bitmap with the same attributes as the DIB.  This behavior is by
 * design, and occurs because this function calls CreateDIBitmap to
 * do its work, and CreateDIBitmap always creates a bitmap compatible
 * with the hDC parameter passed in (because it in turn calls
 * CreateCompatibleBitmap).
 *
 * So for instance, if your DIB is a monochrome DIB and you call this
 * function, you will not get back a monochrome HBITMAP -- you will
 * get an HBITMAP compatible with the screen DC, but with only 2
 * colors used in the bitmap.
 *
 * If your application requires a monochrome HBITMAP returned for a
 * monochrome DIB, use the function SetDIBits().
 *
 * Also, the DIBpassed in to the function is not destroyed on exit. This
 * must be done later, once it is no longer needed.
 *
 * History:   Date      Author               Reason
 *            6/01/91   Garrett McAuliffe    Created
 *            9/15/91   Patrick Schreiber    Added header and comments
 *            3/27/92   Mark Bader           Added comments about resulting
 *                                           bitmap format
 *
 ************************************************************************/


HBITMAP DIBToBitmap(HDIB hDIB, HPALETTE hPal)
{
   LPSTR lpDIBHdr, lpDIBBits;  // pointer to DIB header, pointer to DIB bits
   HBITMAP hBitmap;            // handle to device-dependent bitmap
   HDC hDC;                    // handle to DC
   HPALETTE hOldPal = NULL;    // handle to a palette

   /* if invalid handle, return NULL */

   if (!hDIB)
      return NULL;

   /* lock memory block and get a pointer to it */
   lpDIBHdr = (LPSTR)GlobalLock(hDIB);

   /* get a pointer to the DIB bits */
   lpDIBBits = FindDIBBits(lpDIBHdr);

   /* get a DC */
   hDC = GetDC(NULL);
   if (!hDC)
   {
      /* clean up and return NULL */
      GlobalUnlock(hDIB);
      return NULL;
   }

   /* select and realize palette */
   if (hPal)
      hOldPal = SelectPalette(hDC, hPal, FALSE);
   RealizePalette(hDC);

   /* create bitmap from DIB info. and bits */
   hBitmap = CreateDIBitmap(hDC, (LPBITMAPINFOHEADER)lpDIBHdr, CBM_INIT,
                lpDIBBits, (LPBITMAPINFO)lpDIBHdr, DIB_RGB_COLORS);

   /* restore previous palette */
   if (hOldPal)
      SelectPalette(hDC, hOldPal, FALSE);

   /* clean up */
   ReleaseDC(NULL, hDC);
   GlobalUnlock(hDIB);

   /* return handle to the bitmap */
   return hBitmap;
}

HBITMAP lpDIBToBitmap(void *lpDIBHdr, HPALETTE hPal)
{
   LPSTR lpDIBBits;            // pointer to DIB header, pointer to DIB bits
   HBITMAP hBitmap;            // handle to device-dependent bitmap
   HDC hDC;                    // handle to DC
   HPALETTE hOldPal = NULL;    // handle to a palette

   if (!lpDIBHdr)
      return NULL;

   /* get a pointer to the DIB bits */
   lpDIBBits = FindDIBBits((LPSTR)lpDIBHdr) ;

   /* get a DC */
   hDC = GetDC(NULL);
   if (!hDC)
      return NULL;

   /* select and realize palette */
   if (hPal)
      hOldPal = SelectPalette(hDC, hPal, FALSE);
   RealizePalette(hDC);

   /* create bitmap from DIB info. and bits */
   hBitmap = CreateDIBitmap(hDC, (LPBITMAPINFOHEADER)lpDIBHdr, CBM_INIT,
                lpDIBBits, (LPBITMAPINFO)lpDIBHdr, DIB_RGB_COLORS);

   /* restore previous palette */
   if (hOldPal)
      SelectPalette(hDC, hOldPal, FALSE);

   /* clean up */
   ReleaseDC(NULL, hDC);

   /* return handle to the bitmap */
   return hBitmap;
}

HBITMAP lpDIBToBitmapAndPalette(void *lpDIBHdr)
{
   LPSTR lpDIBBits;            // pointer to DIB header, pointer to DIB bits
   HBITMAP hBitmap;            // handle to device-dependent bitmap
   HDC hDC;                    // handle to DC
   HPALETTE hOldPal;           // handle to a palette

   if (!lpDIBHdr)
      return NULL;

   /* get a pointer to the DIB bits */
   lpDIBBits = FindDIBBits((LPSTR)lpDIBHdr) ;

   /* get a DC */
   hDC = GetDC(NULL);
   if (!hDC)
      return NULL;

   hPalBitmap = pov_frontend::WinLegacyDisplay::CreatePalette (((BITMAPINFO *) lpDIBHdr)->bmiColors, ((BITMAPINFO *) lpDIBHdr)->bmiHeader.biClrImportant, render_bitmap_depth != 24) ;
   if (hPalBitmap)
   {
     hOldPal = SelectPalette(hDC, hPalBitmap, FALSE);
     SelectPalette(hDC, hPalBitmap, FALSE);
     RealizePalette(hDC);
   }

   /* create bitmap from DIB info. and bits */
   hBitmap = CreateDIBitmap(hDC, (LPBITMAPINFOHEADER)lpDIBHdr, CBM_INIT,
                            lpDIBBits, (LPBITMAPINFO)lpDIBHdr, DIB_RGB_COLORS);
   /* restore previous palette */
   if (hPalBitmap)
    if (hOldPal)
        SelectPalette(hDC, hOldPal, FALSE);

   /* clean up */
   ReleaseDC(NULL, hDC);

   /* return handle to the bitmap */
   return hBitmap;
}

/*************************************************************************
 *
 * BitmapToDIB()
 *
 * Parameters:
 *
 * HBITMAP hBitmap  - specifies the bitmap to convert
 *
 * HPALETTE hPal    - specifies the palette to use with the bitmap
 *
 * Return Value:
 *
 * HDIB             - identifies the device-dependent bitmap
 *
 * Description:
 *
 * This function creates a DIB from a bitmap using the specified palette.
 *
 * History:   Date      Author               Reason
 *            6/01/91   Garrett McAuliffe    Created
 *            9/15/91   Patrick Schreiber    Added header and comments
 *            12/10/91  Patrick Schreiber    Added bits per pixel validation
 *                                           and check GetObject return value
 *
 ************************************************************************/


HDIB BitmapToDIB(HBITMAP hBitmap, HPALETTE hPal)
{
   BITMAP bm;                   // bitmap structure
   BITMAPINFOHEADER bi;         // bitmap header
   BITMAPINFOHEADER *lpbi;      // pointer to BITMAPINFOHEADER
   DWORD dwLen;                 // size of memory block
   HANDLE hDIB, h;              // handle to DIB, temp handle
   HDC hDC;                     // handle to DC
   WORD biBits;                 // bits per pixel

   /* check if bitmap handle is valid */

   if (!hBitmap)
      return NULL;

   /* fill in BITMAP structure, return NULL if it didn't work */
   if (!GetObject(hBitmap, sizeof(bm), (LPSTR)&bm))
      return NULL;

   /* if no palette is specified, use default palette */
   if (hPal == NULL)
      hPal = (HPALETTE)GetStockObject(DEFAULT_PALETTE);

   /* calculate bits per pixel */
   biBits = bm.bmPlanes * bm.bmBitsPixel;

   /* make sure bits per pixel is valid */
   if (biBits <= 1)
      biBits = 1;
   else if (biBits <= 4)
      biBits = 4;
   else if (biBits <= 8)
      biBits = 8;
   else /* if greater than 8-bit, force to 24-bit */
      biBits = 24;

   /* initialize BITMAPINFOHEADER */
   bi.biSize = sizeof(BITMAPINFOHEADER);
   bi.biWidth = bm.bmWidth;
   bi.biHeight = bm.bmHeight;
   bi.biPlanes = 1;
   bi.biBitCount = biBits;
   bi.biCompression = BI_RGB;
   bi.biSizeImage = 0;
   bi.biXPelsPerMeter = 0;
   bi.biYPelsPerMeter = 0;
   bi.biClrUsed = 0;
   bi.biClrImportant = 0;

   /* calculate size of memory block required to store BITMAPINFO */
   dwLen = bi.biSize + PaletteSize((LPSTR)&bi);

   /* get a DC */
   hDC = GetDC(NULL);

   /* select and realize our palette */
   hPal = SelectPalette(hDC, hPal, FALSE);
   RealizePalette(hDC);

   /* alloc memory block to store our bitmap */
   hDIB = GlobalAlloc(GHND, dwLen);

   /* if we couldn't get memory block */
   if (!hDIB)
   {
      /* clean up and return NULL */
      SelectPalette(hDC, hPal, TRUE);
      RealizePalette(hDC);
      ReleaseDC(NULL, hDC);
      return NULL;
   }

   /* lock memory and get pointer to it */
   lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDIB);

   /* use our bitmap info. to fill BITMAPINFOHEADER */
   *lpbi = bi;

   /*  call GetDIBits with a NULL lpBits param, so it will calculate the
    *  biSizeImage field for us
    */
   GetDIBits(hDC, hBitmap, 0, (WORD)bi.biHeight, NULL, (LPBITMAPINFO)lpbi,
         DIB_RGB_COLORS);

   /* get the info. returned by GetDIBits and unlock memory block */
   bi = *lpbi;
   GlobalUnlock(hDIB);

   /* if the driver did not fill in the biSizeImage field, make one up */
   if (bi.biSizeImage == 0)
      bi.biSizeImage = WIDTHBYTES((DWORD)bm.bmWidth * biBits) * bm.bmHeight;

   /* realloc the buffer big enough to hold all the bits */
   dwLen = bi.biSize + PaletteSize((LPSTR)&bi) + bi.biSizeImage;
   if ((h = GlobalReAlloc(hDIB, dwLen, 0)) != NULL)
      hDIB = h;
   else
   {
      /* clean up and return NULL */
      GlobalFree(hDIB);
      SelectPalette(hDC, hPal, TRUE);
      RealizePalette(hDC);
      ReleaseDC(NULL, hDC);
      return NULL;
   }

   /* lock memory block and get pointer to it */
   lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDIB);

   /*  call GetDIBits with a NON-NULL lpBits param, and actualy get the
    *  bits this time
    */
   if (GetDIBits(hDC, hBitmap, 0, (WORD)bi.biHeight, (LPSTR)lpbi + (WORD)lpbi
         ->biSize + PaletteSize((LPSTR)lpbi), (LPBITMAPINFO)lpbi,
         DIB_RGB_COLORS) == 0)
   {
      /* clean up and return NULL */
      GlobalUnlock(hDIB);
      SelectPalette(hDC, hPal, TRUE);
      RealizePalette(hDC);
      ReleaseDC(NULL, hDC);
      return NULL;
   }
   bi = *lpbi;

   /* clean up */
   GlobalUnlock(hDIB);
   SelectPalette(hDC, hPal, TRUE);
   RealizePalette(hDC);
   ReleaseDC(NULL, hDC);

   /* return handle to the DIB */
   return hDIB;
}


/*************************************************************************
 *
 * PalEntriesOnDevice()
 *
 * Parameter:
 *
 * HDC hDC          - device context
 *
 * Return Value:
 *
 * int              - number of palette entries on device
 *
 * Description:
 *
 * This function gets the number of palette entries on the specified device
 *
 * History:   Date      Author               Reason
 *            6/01/91   Garrett McAuliffe    Created
 *            9/15/91   Patrick Schreiber    Added header and comments
 *
 ************************************************************************/


int PalEntriesOnDevice(HDC hDC)
{
   int nColors;  // number of colors

   /*  Find out the number of palette entries on this
    *  device.
    */

   nColors = GetDeviceCaps(hDC, SIZEPALETTE);

   /*  For non-palette devices, we'll use the # of system
    *  colors for our palette size.
    */
   if (!nColors)
      nColors = GetDeviceCaps(hDC, NUMCOLORS);
   return nColors;
}


/*************************************************************************
 *
 * GetSystemPalette()
 *
 * Parameters:
 *
 * None
 *
 * Return Value:
 *
 * HPALETTE         - handle to a copy of the current system palette
 *
 * Description:
 *
 * This function returns a handle to a palette which represents the system
 * palette.  The system RGB values are copied into our logical palette using
 * the GetSystemPaletteEntries function.  
 *
 * History:
 *            
 *    Date      Author               Reason        
 *    6/01/91   Garrett McAuliffe    Created        
 *    9/15/91   Patrick Schreiber    Added header and comments
 *    12/20/91  Mark Bader           Added GetSystemPaletteEntries call
 *
 ************************************************************************/


HPALETTE GetSystemPalette(void)
{
   HDC hDC;                // handle to a DC
   static HPALETTE hPal = NULL;   // handle to a palette
   HANDLE hLogPal;         // handle to a logical palette
   LPLOGPALETTE lpLogPal;  // pointer to a logical palette
   int nColors;            // number of colors

   /* Find out how many palette entries we want. */

   hDC = GetDC(NULL);
   if (!hDC)
      return NULL;
   nColors = PalEntriesOnDevice(hDC);   // Number of palette entries

   /* Allocate room for the palette and lock it. */
   hLogPal = GlobalAlloc(GHND, sizeof(LOGPALETTE) + nColors * sizeof(
             PALETTEENTRY));

   /* if we didn't get a logical palette, return NULL */
   if (!hLogPal)
      return NULL;

   /* get a pointer to the logical palette */
   lpLogPal = (LPLOGPALETTE)GlobalLock(hLogPal);

   /* set some important fields */
   lpLogPal->palVersion = PALVERSION;
   lpLogPal->palNumEntries = nColors;

   /* Copy the current system palette into our logical palette */

   GetSystemPaletteEntries(hDC, 0, nColors, 
                           (LPPALETTEENTRY)(lpLogPal->palPalEntry));

   /*  Go ahead and create the palette.  Once it's created,
    *  we no longer need the LOGPALETTE, so free it.
    */

   hPal = CreatePalette(lpLogPal);

   /* clean up */
   GlobalUnlock(hLogPal);
   GlobalFree(hLogPal);
   ReleaseDC(NULL, hDC);

   return hPal;
}


/*************************************************************************
 *
 * AllocRoomForDIB()
 *
 * Parameters:
 *
 * BITMAPINFOHEADER - bitmap info header stucture
 *
 * HBITMAP          - handle to the bitmap
 *
 * Return Value:
 *
 * HDIB             - handle to memory block
 *
 * Description:
 *
 *  This routine takes a BITMAPINOHEADER, and returns a handle to global
 *  memory which can contain a DIB with that header.  It also initializes
 *  the header portion of the global memory.  GetDIBits() is used to determine
 *  the amount of room for the DIB's bits.  The total amount of memory
 *  needed = sizeof(BITMAPINFOHEADER) + size of color table + size of bits.
 *
 * History:   Date      Author               Reason
 *            6/01/91   Garrett McAuliffe    Created
 *            12/11/91  Patrick Schreiber    Added header and some comments
 *
 ************************************************************************/

HANDLE AllocRoomForDIB(BITMAPINFOHEADER bi, HBITMAP hBitmap)
{
   DWORD              dwLen;
   HANDLE             hDIB;
   HDC                hDC;
   LPBITMAPINFOHEADER lpbi;
   HANDLE             hTemp;

   /* Figure out the size needed to hold the BITMAPINFO structure
    * (which includes the BITMAPINFOHEADER and the color table).
    */

   dwLen = bi.biSize + PaletteSize((LPSTR) &bi);
   hDIB  = GlobalAlloc(GHND,dwLen);

   /* Check that DIB handle is valid */
   if (!hDIB)
      return NULL;

   /* Set up the BITMAPINFOHEADER in the newly allocated global memory,
    * then call GetDIBits() with lpBits = NULL to have it fill in the
    * biSizeImage field for us.
    */
   lpbi  = (LPBITMAPINFOHEADER)GlobalLock(hDIB);
   *lpbi = bi;

   hDC   = GetDC(NULL);
   GetDIBits(hDC, hBitmap, 0, (WORD) bi.biHeight,
          NULL, (LPBITMAPINFO) lpbi, DIB_RGB_COLORS);
   ReleaseDC(NULL, hDC);

   /* If the driver did not fill in the biSizeImage field,
    * fill it in -- NOTE: this is a bug in the driver!
    */
   if (lpbi->biSizeImage == 0)
      lpbi->biSizeImage = WIDTHBYTES((DWORD)lpbi->biWidth * lpbi->biBitCount) *
              lpbi->biHeight;

   /* Get the size of the memory block we need */
   dwLen = lpbi->biSize + PaletteSize((LPSTR) &bi) + lpbi->biSizeImage;

   /* Unlock the memory block */
   GlobalUnlock(hDIB);

   /* ReAlloc the buffer big enough to hold all the bits */
   if ((hTemp = GlobalReAlloc(hDIB,dwLen,0)) != NULL)
      return hTemp;
   else
      {
      /* Else free memory block and return failure */
      GlobalFree(hDIB);
      return NULL;
      }
}


/*************************************************************************
 *
 * ChangeDIBFormat()
 *
 * Parameter:
 *
 * HDIB             - handle to packed-DIB in memory
 *
 * WORD             - desired bits per pixel
 *
 * DWORD            - desired compression format
 *
 * Return Value:
 *
 * HDIB             - handle to the new DIB if successful, else NULL
 *
 * Description:
 *
 * This function will convert the bits per pixel and/or the compression
 * format of the specified DIB. Note: If the conversion was unsuccessful,
 * we return NULL. The original DIB is left alone. Don't use code like the
 * following:
 *
 *    hMyDIB = ChangeDIBFormat(hMyDIB, 8, BI_RLE4);
 *
 * The conversion will fail, but hMyDIB will now be NULL and the original
 * DIB will now hang around in memory. We could have returned the old
 * DIB, but we wanted to allow the programmer to check whether this
 * conversion succeeded or failed.
 *
 * History:   
 *            
 *   Date      Author             Reason         
 *   6/01/91   Garrett McAuliffe  Created         
 *   12/10/91  Patrick Schreiber  Modified from converting RGB to RLE8        
 *                                  to converting RGB/RLE to RGB/RLE.         
 *                                  Added wBitCount and dwCompression         
 *                                  parameters. Also added header and         
 *                                  comments.         
 *
 ************************************************************************/

HDIB ChangeDIBFormat(HDIB hDIB, WORD wBitCount, DWORD dwCompression)
{
   HDC                hDC;             // Handle to DC
   HBITMAP            hBitmap;         // Handle to bitmap
   BITMAP             Bitmap;          // BITMAP data structure
   BITMAPINFOHEADER   bi;              // Bitmap info header
   LPBITMAPINFOHEADER lpbi;            // Pointer to bitmap info
   HDIB               hNewDIB;         // Handle to new DIB
   HPALETTE           hPal, hOldPal;   // Handle to palette, prev pal
   WORD               DIBBPP, NewBPP;  // DIB bits per pixel, new bpp
   DWORD              NewComp;         // New compression

   /* Check for a valid DIB handle */
   if (!hDIB)
      return NULL;

   /* Get the old DIB's bits per pixel and compression format */
   lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDIB);
   DIBBPP = ((LPBITMAPINFOHEADER)lpbi)->biBitCount;
   GlobalUnlock(hDIB);

   /* Validate wBitCount and dwCompression
    * They must match correctly (i.e., BI_RLE4 and 4 BPP or
    * BI_RLE8 and 8BPP, etc.) or we return failure */
   if (wBitCount == 0)
      {
      NewBPP = DIBBPP;
      if ((dwCompression == BI_RLE4 && NewBPP == 4) ||
      (dwCompression == BI_RLE8 && NewBPP == 8) ||
      (dwCompression == BI_RGB))
     NewComp = dwCompression;
      else
     return NULL;
      }
   else if (wBitCount == 1 && dwCompression == BI_RGB)
      {
      NewBPP = wBitCount;
      NewComp = BI_RGB;
      }
   else if (wBitCount == 4)
      {
      NewBPP = wBitCount;
      if (dwCompression == BI_RGB || dwCompression == BI_RLE4)
     NewComp = dwCompression;
      else
     return NULL;
      }
   else if (wBitCount == 8)
      {
      NewBPP = wBitCount;
      if (dwCompression == BI_RGB || dwCompression == BI_RLE8)
     NewComp = dwCompression;
      else
     return NULL;
      }
   else if (wBitCount == 24 && dwCompression == BI_RGB)
      {
      NewBPP = wBitCount;
      NewComp = BI_RGB;
      }
   else
      return NULL;

   /* Save the old DIB's palette */
   hPal = CreateDIBPalette(hDIB);
   if (!hPal)
      return NULL;

   /* Convert old DIB to a bitmap */
   hBitmap = DIBToBitmap(hDIB, hPal);
   if (!hBitmap)
      {
      DeleteObject(hPal);
      return NULL;
      }

   /* Get info about the bitmap */
   GetObject(hBitmap, sizeof(BITMAP), (LPSTR)&Bitmap);

   /* Fill in the BITMAPINFOHEADER appropriately */
   bi.biSize               = sizeof(BITMAPINFOHEADER);
   bi.biWidth              = Bitmap.bmWidth;
   bi.biHeight             = Bitmap.bmHeight;
   bi.biPlanes             = 1;
   bi.biBitCount           = NewBPP;
   bi.biCompression        = NewComp;
   bi.biSizeImage          = 0;
   bi.biXPelsPerMeter      = 0;
   bi.biYPelsPerMeter      = 0;
   bi.biClrUsed            = 0;
   bi.biClrImportant       = 0;

   /* Go allocate room for the new DIB */
   hNewDIB = AllocRoomForDIB(bi, hBitmap);
   if (!hNewDIB)
      return NULL;

   /* Get a pointer to the new DIB */
   lpbi = (LPBITMAPINFOHEADER)GlobalLock(hNewDIB);

   /* Get a DC and select/realize our palette in it */
   hDC  = GetDC(NULL);
   hOldPal = SelectPalette(hDC, hPal, FALSE);
   RealizePalette(hDC);

   /* Call GetDIBits and get the new DIB bits */
   if (!GetDIBits(hDC, hBitmap, 0, (WORD) lpbi->biHeight,
       (LPSTR)lpbi + (WORD)lpbi->biSize + PaletteSize((LPSTR)lpbi),
       (LPBITMAPINFO)lpbi, DIB_RGB_COLORS))
      {
      GlobalUnlock(hNewDIB);
      GlobalFree(hNewDIB);
      hNewDIB = NULL;
      }

   /* Clean up and return */
   SelectPalette(hDC, hOldPal, TRUE);
   RealizePalette(hDC);
   ReleaseDC(NULL, hDC);

   if (hNewDIB)
      /* Unlock the new DIB's memory block */
      GlobalUnlock(hNewDIB);

   DeleteObject(hBitmap);
   DeleteObject(hPal);

   return hNewDIB;
}


/*************************************************************************
 *
 * ChangeBitmapFormat()
 *
 * Parameter:
 *
 * HBITMAP          - handle to a bitmap
 *
 * WORD             - desired bits per pixel
 *
 * DWORD            - desired compression format
 *
 * HPALETTE         - handle to palette
 *
 * Return Value:
 *
 * HDIB             - handle to the new DIB if successful, else NULL
 *
 * Description:
 *
 * This function will convert a bitmap to the specified bits per pixel
 * and compression format. The bitmap and it's palette will remain
 * after calling this function.
 *
 * History:   
 *            
 *   Date      Author             Reason
 *   6/01/91   Garrett McAuliffe  Created         
 *   12/10/91  Patrick Schreiber  Modified from converting RGB to RLE8         
 *                                 to converting RGB/RLE to RGB/RLE.         
 *                                 Added wBitCount and dwCompression         
 *                                 parameters. Also added header and         
 *                                 comments.         
 *   12/11/91  Patrick Schreiber  Destroy old DIB if conversion was         
 *                                 successful.         
 *   12/16/91  Patrick Schreiber  Modified from converting DIB to new         
 *                                 DIB to bitmap to new DIB. Added palette
 *                                 parameter.
 *
 ************************************************************************/

HDIB ChangeBitmapFormat(HBITMAP  hBitmap,
            WORD     wBitCount,
            DWORD    dwCompression,
            HPALETTE hPal)
{
   HDC                hDC;          // Screen DC
   HDIB               hNewDIB;      // Handle to new DIB
   BITMAP             Bitmap;       // BITMAP data structure
   BITMAPINFOHEADER   bi;           // Bitmap info. header
   LPBITMAPINFOHEADER lpbi;         // Pointer to bitmap header
   HPALETTE           hOldPal=NULL; // Handle to palette
   WORD               NewBPP;       // New bits per pixel
   DWORD              NewComp;      // New compression format

   /* Check for a valid bitmap handle */
   if (!hBitmap)
      return NULL;

   /* Validate wBitCount and dwCompression
    * They must match correctly (i.e., BI_RLE4 and 4 BPP or
    * BI_RLE8 and 8BPP, etc.) or we return failure
    */
   if (wBitCount == 0)
      {
      NewComp = dwCompression;
      if (NewComp == BI_RLE4)
     NewBPP = 4;
      else if (NewComp == BI_RLE8)
     NewBPP = 8;
      else /* Not enough info */
     return NULL;
      }
   else if (wBitCount == 1 && dwCompression == BI_RGB)
      {
      NewBPP = wBitCount;
      NewComp = BI_RGB;
      }
   else if (wBitCount == 4)
      {
      NewBPP = wBitCount;
      if (dwCompression == BI_RGB || dwCompression == BI_RLE4)
         NewComp = dwCompression;
      else
         return NULL;
      }
   else if (wBitCount == 8)
      {
      NewBPP = wBitCount;
      if (dwCompression == BI_RGB || dwCompression == BI_RLE8)
         NewComp = dwCompression;
      else
         return NULL;
      }
   else if (wBitCount == 24 && dwCompression == BI_RGB)
      {
      NewBPP = wBitCount;
      NewComp = BI_RGB;
      }
   else
      return NULL;

   /* Get info about the bitmap */
   GetObject(hBitmap, sizeof(BITMAP), (LPSTR)&Bitmap);

   /* Fill in the BITMAPINFOHEADER appropriately */
   bi.biSize               = sizeof(BITMAPINFOHEADER);
   bi.biWidth              = Bitmap.bmWidth;
   bi.biHeight             = Bitmap.bmHeight;
   bi.biPlanes             = 1;
   bi.biBitCount           = NewBPP;
   bi.biCompression        = NewComp;
   bi.biSizeImage          = 0;
   bi.biXPelsPerMeter      = 0;
   bi.biYPelsPerMeter      = 0;
   bi.biClrUsed            = 0;
   bi.biClrImportant       = 0;

   /* Go allocate room for the new DIB */
   hNewDIB = AllocRoomForDIB(bi, hBitmap);
   if (!hNewDIB)
      return NULL;

   /* Get a pointer to the new DIB */
   lpbi = (LPBITMAPINFOHEADER)GlobalLock(hNewDIB);

   /* If we have a palette, get a DC and select/realize it */
   if (hPal)
   {
      hDC  = GetDC(NULL);
      hOldPal = SelectPalette(hDC, hPal, FALSE);
      RealizePalette(hDC);
   }

   /* Call GetDIBits and get the new DIB bits */
   if (!GetDIBits(hDC, hBitmap, 0, (WORD) lpbi->biHeight,
       (LPSTR)lpbi + (WORD)lpbi->biSize + PaletteSize((LPSTR)lpbi),
       (LPBITMAPINFO)lpbi, DIB_RGB_COLORS))
      {
      GlobalUnlock(hNewDIB);
      GlobalFree(hNewDIB);
      hNewDIB = NULL;
      }

   /* Clean up and return */
   if (hOldPal)
   {
      SelectPalette(hDC, hOldPal, TRUE);
      RealizePalette(hDC);
      ReleaseDC(NULL, hDC);
   }

   if (hNewDIB)
      {
      /* Unlock the new DIB's memory block */
      GlobalUnlock(hNewDIB);
      }

   return hNewDIB;
}

/*************************************************************************
 *
 * LoadDIB()
 *
 * Loads the specified DIB from a file, allocates memory for it,
 * and reads the disk file into the memory.
 *
 *
 * Parameters:
 *
 * LPSTR lpFileName - specifies the file to load a DIB from
 *
 * Returns: A handle to a DIB, or NULL if unsuccessful.
 *
 * NOTE: The DIB API were not written to handle OS/2 DIBs; This
 * function will reject any file that is not a Windows DIB.
 *
 * History:   Date      Author       Reason
 *            9/15/91   Mark Bader   Based on DIBVIEW
 *
 *************************************************************************/

HDIB LoadDIB(LPSTR lpFileName)
{
   HDIB hDIB;
   int hFile;
   OFSTRUCT ofs;

   /*
    * Set the cursor to a hourglass, in case the loading operation
    * takes more than a sec, the user will know what's going on.
    */

   SetCursor(LoadCursor(NULL, IDC_WAIT));
   if ((hFile = OpenFile(lpFileName, &ofs, OF_READ)) != -1)
   {
      hDIB = ReadDIBFile(hFile);
      _lclose(hFile);
      SetCursor(LoadCursor(NULL, IDC_ARROW));
      return hDIB;
   }
   else
   {
      SetCursor(LoadCursor(NULL, IDC_ARROW));
      return NULL;
   }
}

/*************************************************************************
 *
 * SaveDIB()
 *
 * Saves the specified DIB into the specified file name on disk.  No
 * error checking is done, so if the file already exists, it will be
 * written over.
 *
 * Parameters:
 *
 * HDIB hDib - Handle to the dib to save
 *
 * LPSTR lpFileName - pointer to full pathname to save DIB under
 *
 * Return value: 0 if successful, or one of:
 *        ERR_INVALIDHANDLE
 *        ERR_OPEN
 *        ERR_LOCK
 *
 * History:
 *
 * NOTE: The DIB API were not written to handle OS/2 DIBs, so this
 * function will not save a file if it is not a Windows DIB.
 *
 * History:   Date      Author       Reason
 *            9/15/91   Mark Bader   Taken from DIBVIEW (which was taken
 *                                      from SHOWDIB)
 *            1/30/92   Mark Bader   Fixed problem of writing too many
 *                                      bytes to the file
 *            6/24/92   Mark Bader   Added check for OS/2 DIB
 *
 *************************************************************************/


WORD SaveDIB(HDIB hDib, LPSTR lpFileName)
{
   BITMAPFILEHEADER bmfHdr; // Header for Bitmap file
   LPBITMAPINFOHEADER lpBI;   // Pointer to DIB info structure
   int fh;     // file handle for opened file
   OFSTRUCT of;     // OpenFile structure
   DWORD dwDIBSize;
   DWORD dwError;   // Error return from MyWrite

   if (!hDib)
      return ERR_INVALIDHANDLE;
   fh = OpenFile(lpFileName, &of, OF_CREATE | OF_READWRITE);
   if (fh == -1)
      return ERR_OPEN;

   /*
    * Get a pointer to the DIB memory, the first of which contains
    * a BITMAPINFO structure
    */
   lpBI = (LPBITMAPINFOHEADER)GlobalLock(hDib);
   if (!lpBI)
      return ERR_LOCK;

   // Check to see if we're dealing with an OS/2 DIB.  If so, don't
   // save it because our functions aren't written to deal with these
   // DIBs.

   if (lpBI->biSize != sizeof(BITMAPINFOHEADER))
   {
     GlobalUnlock(hDib);
     return ERR_NOT_DIB;
   }

   /*
    * Fill in the fields of the file header
    */

   /* Fill in file type (first 2 bytes must be "BM" for a bitmap) */
   bmfHdr.bfType = DIB_HEADER_MARKER;  // "BM"

   // Calculating the size of the DIB is a bit tricky (if we want to
   // do it right).  The easiest way to do this is to call GlobalSize()
   // on our global handle, but since the size of our global memory may have
   // been padded a few bytes, we may end up writing out a few too
   // many bytes to the file (which may cause problems with some apps,
   // like HC 3.0).
   //
   // So, instead let's calculate the size manually.
   //
   // To do this, find size of header plus size of color table.  Since the
   // first DWORD in both BITMAPINFOHEADER and BITMAPCOREHEADER conains
   // the size of the structure, let's use this.

   dwDIBSize = *(LPDWORD)lpBI + PaletteSize((LPSTR)lpBI);  // Partial Calculation

   // Now calculate the size of the image

   if ((lpBI->biCompression == BI_RLE8) || (lpBI->biCompression == BI_RLE4)) {

      // It's an RLE bitmap, we can't calculate size, so trust the
      // biSizeImage field

      dwDIBSize += lpBI->biSizeImage;
      }
   else {
      DWORD dwBmBitsSize;  // Size of Bitmap Bits only

      // It's not RLE, so size is Width (DWORD aligned) * Height

      dwBmBitsSize = WIDTHBYTES((lpBI->biWidth)*((DWORD)lpBI->biBitCount)) * lpBI->biHeight;

      dwDIBSize += dwBmBitsSize;

      // Now, since we have calculated the correct size, why don't we
      // fill in the biSizeImage field (this will fix any .BMP files which
      // have this field incorrect).

      lpBI->biSizeImage = dwBmBitsSize;
      }


   // Calculate the file size by adding the DIB size to sizeof(BITMAPFILEHEADER)

   bmfHdr.bfSize = dwDIBSize + sizeof(BITMAPFILEHEADER);
   bmfHdr.bfReserved1 = 0;
   bmfHdr.bfReserved2 = 0;

   /*
    * Now, calculate the offset the actual bitmap bits will be in
    * the file -- It's the Bitmap file header plus the DIB header,
    * plus the size of the color table.
    */
   bmfHdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + lpBI->biSize +
                      PaletteSize((LPSTR)lpBI);

   /* Write the file header */
   _lwrite(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER));

   /*
    * Write the DIB header and the bits -- use local version of
    * MyWrite, so we can write more than 32767 bytes of data
    */
   dwError = MyWrite(fh, (LPSTR)lpBI, dwDIBSize);
   GlobalUnlock(hDib);
   _lclose(fh);

   if (dwError == 0)
     return ERR_OPEN; // oops, something happened in the write
   else
     return 0; // Success code
}


/*************************************************************************
 *
 * DestroyDIB ()
 *
 * Purpose:  Frees memory associated with a DIB
 *
 * Returns:  Nothing
 *
 * History:   Date      Author       Reason
 *            9/15/91   Mark Bader   Created
 *
 *************************************************************************/


WORD DestroyDIB(HDIB hDib)
{
   GlobalFree(hDib);
   return 0;
}


//************************************************************************
//
// Auxiliary Functions which the above procedures use
//
//************************************************************************


/*************************************************************************
 *
 * Function:  ReadDIBFile (int)
 *
 *  Purpose:  Reads in the specified DIB file into a global chunk of
 *            memory.
 *
 *  Returns:  A handle to a dib (hDIB) if successful.
 *            NULL if an error occurs.
 *
 * Comments:  BITMAPFILEHEADER is stripped off of the DIB.  Everything
 *            from the end of the BITMAPFILEHEADER structure on is
 *            returned in the global memory handle.
 *
 *
 * NOTE: The DIB API were not written to handle OS/2 DIBs, so this
 * function will reject any file that is not a Windows DIB.
 *
 * History:   Date      Author       Reason
 *            9/15/91   Mark Bader   Based on DIBVIEW
 *            6/25/92   Mark Bader   Added check for OS/2 DIB
 *            7/21/92   Mark Bader   Added code to deal with bfOffBits
 *                                     field in BITMAPFILEHEADER
 *            9/11/92   Mark Bader   Fixed Realloc Code to free original mem
 *
 *************************************************************************/

HANDLE ReadDIBFile(int hFile)
{
   BITMAPFILEHEADER bmfHeader;
   UINT nNumColors;   // Number of colors in table
   HANDLE hDIB;
   HANDLE hDIBtmp;    // Used for GlobalRealloc() //MPB
   LPBITMAPINFOHEADER lpbi;
   DWORD offBits;

   /*
    * get length of DIB in bytes for use when reading
    */

   // Allocate memory for header & color table.	We'll enlarge this
   // memory as needed.

   hDIB = GlobalAlloc(GMEM_MOVEABLE,
       (DWORD)(sizeof(BITMAPINFOHEADER) + 256 * sizeof(RGBQUAD)));

   if (!hDIB) return NULL;

   lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDIB);
   if (!lpbi)
   {
     GlobalFree(hDIB);
     return NULL;
   }

   // read the BITMAPFILEHEADER from our file

   if (sizeof (BITMAPFILEHEADER) != _lread (hFile, (LPSTR)&bmfHeader, sizeof (BITMAPFILEHEADER)))
     goto ErrExit;

   if (bmfHeader.bfType != 0x4d42)	/* 'BM' */
     goto ErrExit;

   // read the BITMAPINFOHEADER

   if (sizeof(BITMAPINFOHEADER) != _lread (hFile, (LPSTR)lpbi, sizeof(BITMAPINFOHEADER)))
     goto ErrExit;

   // Check to see that it's a Windows DIB -- an OS/2 DIB would cause
   // strange problems with the rest of the DIB API since the fields
   // in the header are different and the color table entries are
   // smaller.
   //
   // If it's not a Windows DIB (e.g. if biSize is wrong), return NULL.

   if (lpbi->biSize == sizeof(BITMAPCOREHEADER))
     goto ErrExit;

   // Now determine the size of the color table and read it.  Since the
   // bitmap bits are offset in the file by bfOffBits, we need to do some
   // special processing here to make sure the bits directly follow
   // the color table (because that's the format we are susposed to pass
   // back)

   if (!(nNumColors = (UINT)lpbi->biClrUsed))
    {
      // no color table for 24-bit, default size otherwise
      if (lpbi->biBitCount != 24)
        nNumColors = 1 << lpbi->biBitCount; /* standard size table */
    }

   // fill in some default values if they are zero
   if (lpbi->biClrUsed == 0)
     lpbi->biClrUsed = nNumColors;

   if (lpbi->biSizeImage == 0)
   {
     lpbi->biSizeImage = ((((lpbi->biWidth * (DWORD)lpbi->biBitCount) + 31) & ~31) >> 3)
			 * lpbi->biHeight;
   }

   // get a proper-sized buffer for header, color table and bits
   GlobalUnlock(hDIB);
   hDIBtmp = GlobalReAlloc(hDIB, lpbi->biSize +
                        nNumColors * sizeof(RGBQUAD) +
                        lpbi->biSizeImage, 0);

   if (!hDIBtmp) // can't resize buffer for loading
     goto ErrExitNoUnlock; //MPB
   else
     hDIB = hDIBtmp;

   lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDIB);

   // read the color table
   _lread (hFile, (LPSTR)(lpbi) + lpbi->biSize, nNumColors * sizeof(RGBQUAD));

   // offset to the bits from start of DIB header
   offBits = lpbi->biSize + nNumColors * sizeof(RGBQUAD);

   // If the bfOffBits field is non-zero, then the bits might *not* be
   // directly following the color table in the file.  Use the value in
   // bfOffBits to seek the bits.

   if (bmfHeader.bfOffBits != 0L)
      _llseek(hFile, bmfHeader.bfOffBits, SEEK_SET);

   if (MyRead(hFile, (LPSTR)lpbi + offBits, lpbi->biSizeImage))
     goto OKExit;


ErrExit:
    GlobalUnlock(hDIB);
ErrExitNoUnlock:
    GlobalFree(hDIB);
    return NULL;

OKExit:
    GlobalUnlock(hDIB);
    return hDIB;
}

/*************************************************************************

  Function:  MyRead (int, LPSTR, DWORD)

   Purpose:  Routine to read files greater than 64K in size.

   Returns:  TRUE if successful.
             FALSE if an error occurs.


  History:   Date      Author       Reason
             9/15/91   Mark Bader   Based on DIBVIEW

*************************************************************************/


bool MyRead(int hFile, LPSTR lpBuffer, DWORD dwSize)
{
   char *lpInBuf = (char *)lpBuffer;
   int nBytes;

   /*
    * Read in the data in 32767 byte chunks (or a smaller amount if it's
    * the last chunk of data read)
    */

   while (dwSize)
   {
      nBytes = (int)(dwSize > (DWORD)32767 ? 32767 : LOWORD (dwSize));
      if (_lread(hFile, (LPSTR)lpInBuf, nBytes) != (WORD)nBytes)
         return FALSE;
      dwSize -= nBytes;
      lpInBuf += nBytes;
   }
   return TRUE;
}


/****************************************************************************

 FUNCTION   : MyWrite(int fh, VOID *pv, DWORD ul)

 PURPOSE    : Writes data in steps of 32k till all the data is written.
              Normal _lwrite uses a WORD as 3rd parameter, so it is
              limited to 32767 bytes, but this procedure is not.

 RETURNS    : 0 - If write did not proceed correctly.
              number of bytes written otherwise.

  History:   Date      Author       Reason
             9/15/91   Mark Bader   Based on DIBVIEW

 ****************************************************************************/


DWORD PASCAL MyWrite(int iFileHandle, VOID *lpBuffer, DWORD dwBytes)
{
   DWORD dwBytesTmp = dwBytes;       // Save # of bytes for return value
   BYTE *hpBuffer = (BYTE *)lpBuffer;   // make a huge pointer to the data

   /*
    * Write out the data in 32767 byte chunks.
    */

   while (dwBytes > 32767)
   {
      if (_lwrite(iFileHandle, (LPSTR)hpBuffer, (WORD)32767) != 32767)
         return 0;
      dwBytes -= 32767;
      hpBuffer += 32767;
   }

   /* Write out the last chunk (which is < 32767 bytes) */
   if (_lwrite(iFileHandle, (LPSTR)hpBuffer, (WORD)dwBytes) != (WORD)dwBytes)
      return 0;
   return dwBytesTmp;
}

}