small change to avoid floating point exception in wxScrolledWindow::Scroll

[wxWidgets.git] / src / msw / dib.cpp

/*******************************************************************************
 *                                                                               *
 * MODULE        : DIB.CC                                                        *
 *                                                                               *
 *  DESCRIPTION : Routines for dealing with Device Independent Bitmaps.        *
 *                                                                               *
 *  FUNCTIONS        :                                                              *
 *                                                                               *
 *                wxReadDIB()           - Reads a DIB                            *
 *                                                                               *
 *                  WriteDIB()              - Writes a global handle in CF_DIB format*
 *                                        to a file.                               *
 *                                                                               *
 *                  wxPaletteSize()       - Calculates the palette size in bytes   *
 *                                        of given DIB                               *
 *                                                                               *
 *                  DibNumColors()      - Determines the number of colors in DIB *
 *                                                                               *
 *                  DibFromBitmap()     - Creates a DIB repr. the DDB passed in. *
 *                                                                               *
 *                                                                               *
 *                  lread()              - Private routine to read more than 64k  *
 *                                                                               *
 *                  lwrite()              - Private routine to write more than 64k *
 *                                                                               *
 *******************************************************************************/

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#if defined(__BORLANDC__)
#pragma hdrstop
#endif

#ifndef WX_PRECOMP
#include "wx/bitmap.h"
#include "wx/log.h"
#include "wx/intl.h"
#endif

#include <windows.h>
#include <stdio.h>
#include <stdlib.h>

#if !defined(__MWERKS__) && !defined(__SALFORDC__)
#include <memory.h>
#endif

#include "wx/msw/dib.h"

#ifdef __GNUWIN32_OLD__
    #include "wx/msw/gnuwin32/extra.h"
#endif

#ifndef SEEK_CUR
/* flags for _lseek */
#define        SEEK_CUR 1
#define        SEEK_END 2
#define        SEEK_SET 0
#endif

#define MAXREAD  32768                                 /* Number of bytes to be read during */
                                                 /* each read operation.                         */

/* Header signatutes for various resources */
#define BFT_ICON         0x4349         /* 'IC' */
#define BFT_BITMAP 0x4d42         /* 'BM' */
#define BFT_CURSOR 0x5450         /* 'PT(' */

/* macro to determine if resource is a DIB */
#define ISDIB(bft) ((bft) == BFT_BITMAP)

/* Macro to align given value to the closest DWORD (unsigned long ) */
#define ALIGNULONG(i)        ((i+3)/4*4)

/* Macro to determine to round off the given value to the closest byte */
#define WIDTHBYTES(i)        ((i+31)/32*4)

#define PALVERSION                0x300
#define MAXPALETTE        256          /* max. # supported palette entries */

static DWORD PASCAL lread(int fh, VOID FAR *pv, DWORD ul);
static DWORD PASCAL lwrite(int fh, VOID FAR *pv, DWORD ul);

static BOOL        WriteDIB (LPTSTR szFile,HANDLE hdib);
WORD        wxPaletteSize (VOID FAR * pv); // This is non-static as some apps use it externally
static WORD        DibNumColors (VOID FAR * pv);
// HANDLE        DibFromBitmap (HBITMAP hbm, DWORD biStyle, WORD biBits, HPALETTE hpal);
static BOOL PASCAL MakeBitmapAndPalette(HDC,HANDLE,HPALETTE *,HBITMAP *);

/****************************************************************************
 *                                                                            *
 *  FUNCTION   : WriteDIB(LPSTR szFile,HANDLE hdib)                            *
 *                                                                            *
 *  PURPOSE    : Write a global handle in CF_DIB format to a file.            *
 *                                                                            *
 *  RETURNS    : TRUE  - if successful.                                     *
 *                 FALSE - otherwise                                            *
 *                                                                            *
 ****************************************************************************/

static BOOL WriteDIB(LPTSTR szFile, HANDLE hdib)
{
        BITMAPFILEHEADER        hdr;
        LPBITMAPINFOHEADER  lpbi;
        int                 fh;
        OFSTRUCT            of;

        if (!hdib)
                return FALSE;

        fh = OpenFile(wxFNCONV(szFile), &of, OF_CREATE | OF_READWRITE);
        if (fh == -1)
                return FALSE;

#ifdef __WINDOWS_386__
        lpbi = (LPBITMAPINFOHEADER) MK_FP32(GlobalLock(hdib));
#else
        lpbi = (LPBITMAPINFOHEADER) GlobalLock(hdib);
#endif
    /* Fill in the fields of the file header */
        hdr.bfType = BFT_BITMAP;
        hdr.bfSize = GlobalSize(hdib) + sizeof(BITMAPFILEHEADER);
        hdr.bfReserved1 = 0;
        hdr.bfReserved2 = 0;
        hdr.bfOffBits = (DWORD) sizeof(BITMAPFILEHEADER) + lpbi->biSize +
                 wxPaletteSize(lpbi);

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

    /* Write the DIB header and the bits */
        lwrite(fh, (LPSTR) lpbi, GlobalSize(hdib));

        GlobalUnlock(hdib);
        _lclose(fh);
        return TRUE;
}

/****************************************************************************
 *                                                                            *
 *  FUNCTION   :  wxPaletteSize(VOID FAR * pv)                                    *
 *                                                                            *
 *  PURPOSE    :  Calculates the palette size in bytes. If the info. block  *
 *                  is of the BITMAPCOREHEADER type, the number of colors is  *
 *                  multiplied by 3 to give the palette size, otherwise the   *
 *                  number of colors is multiplied by 4.                                                                *
 *                                                                            *
 *  RETURNS    :  Palette size in number of bytes.                            *
 *                                                                            *
 ****************************************************************************/

WORD wxPaletteSize(VOID FAR * pv)
{
        LPBITMAPINFOHEADER lpbi;
        WORD               NumColors;

        lpbi = (LPBITMAPINFOHEADER) pv;
        NumColors = DibNumColors(lpbi);

        if (lpbi->biSize == sizeof(BITMAPCOREHEADER))
                return NumColors * sizeof(RGBTRIPLE);
        else
                return NumColors * sizeof(RGBQUAD);
}

/****************************************************************************
 *                                                                            *
 *  FUNCTION   : DibNumColors(VOID FAR * pv)                                    *
 *                                                                            *
 *  PURPOSE    : Determines the number of colors in the DIB by looking at   *
 *                 the BitCount filed in the info block.                            *
 *                                                                            *
 *  RETURNS    : The number of colors in the DIB.                            *
 *                                                                            *
 ****************************************************************************/

static WORD DibNumColors(VOID FAR *pv)
{
        int                 bits;
        BITMAPINFOHEADER        *lpbi;
        BITMAPCOREHEADER        *lpbc;

        lpbi = ((BITMAPINFOHEADER*) pv);
        lpbc = ((BITMAPCOREHEADER*) pv);

    /*        With the BITMAPINFO format headers, the size of the palette
     *        is in biClrUsed, whereas in the BITMAPCORE - style headers, it
     *        is dependent on the bits per pixel ( = 2 raised to the power of
     *        bits/pixel).
     */
        if (lpbi->biSize != sizeof(BITMAPCOREHEADER)) {
                if (lpbi->biClrUsed != 0)
                        return (WORD) lpbi->biClrUsed;
                bits = lpbi->biBitCount;
                }
        else
                bits = lpbc->bcBitCount;

        switch (bits) {
  case 1:
                return 2;
  case 4:
                return 16;
  case 8:
                return 256;
  default:
                /* A 24 bitcount DIB has no color table */
                return 0;
                }
}

/****************************************************************************
 *                                                                            *
 *  FUNCTION   : DibFromBitmap()                                            *
 *                                                                            *
 *  PURPOSE    : Will create a global memory block in DIB format that            *
 *                 represents the Device-dependent bitmap (DDB) passed in.    *
 *                                                                            *
 *  RETURNS    : A handle to the DIB                                            *
 *                                                                            *
 ****************************************************************************/

#if NOTHING
static HANDLE DibFromBitmap(HBITMAP hbm, DWORD biStyle, WORD biBits, HPALETTE hpal)
{
        BITMAP               bm;
        BITMAPINFOHEADER     bi;
        BITMAPINFOHEADER FAR *lpbi;
        DWORD                dwLen;
        HANDLE               hdib;
        HANDLE               h;
        HDC                  hdc;

        if (!hbm)
                return NULL;

        if (hpal == NULL)
                hpal = GetStockObject(DEFAULT_PALETTE);

        GetObject(hbm, sizeof (bm), (LPSTR) &bm);

        if (biBits == 0)
                biBits = bm.bmPlanes * bm.bmBitsPixel;

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

        dwLen = bi.biSize + wxPaletteSize(&bi);

        hdc = GetDC((HWND) NULL);
        hpal = SelectPalette(hdc, hpal, FALSE);
        RealizePalette(hdc);

        hdib = GlobalAlloc(GHND, dwLen);

        if (!hdib) {
                SelectPalette(hdc, hpal, FALSE);
                ReleaseDC(NULL, hdc);
                return NULL;
                }

#ifdef __WINDOWS_386__
        lpbi = (BITMAPINFOHEADER FAR *) MK_FP32(GlobalLock(hdib));
#else
        lpbi = (BITMAPINFOHEADER FAR *) GlobalLock(hdib);
#endif

        *lpbi = bi;

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

        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;

                if (biStyle != BI_RGB)
                        bi.biSizeImage = (bi.biSizeImage * 3) / 2;
                }

    /*        realloc the buffer big enough to hold all the bits */
        dwLen = bi.biSize + wxPaletteSize(&bi) + bi.biSizeImage;
        if (h = GlobalReAlloc(hdib, dwLen, 0))
                hdib = h;
        else {
                GlobalFree(hdib);
                hdib = NULL;

                SelectPalette(hdc, hpal, FALSE);
                ReleaseDC(NULL, hdc);
                return hdib;
                }

    /*        call GetDIBits with a NON-NULL lpBits param, and actualy get the
     *  bits this time
     */
#ifdef __WINDOWS_386__
        lpbi = (BITMAPINFOHEADER FAR *) MK_FP32(GlobalLock(hdib));
#else
        lpbi = (BITMAPINFOHEADER FAR *) GlobalLock(hdib);
#endif

        if (GetDIBits(hdc,
                 hbm,
                 0,
                 (WORD) bi.biHeight,
                 (LPSTR) lpbi + (WORD) lpbi->biSize + wxPaletteSize(lpbi),
                 (LPBITMAPINFO) lpbi, DIB_RGB_COLORS) == 0) {
                GlobalUnlock(hdib);
                hdib = NULL;
                SelectPalette(hdc, hpal, FALSE);
                ReleaseDC((HWND) NULL, hdc);
                return NULL;
                }

        bi = *lpbi;
        GlobalUnlock(hdib);

        SelectPalette(hdc, hpal, FALSE);
        ReleaseDC(NULL, hdc);
        return hdib;
}
#endif

 /************* PRIVATE ROUTINES TO READ/WRITE MORE THAN 64K ***************/
/****************************************************************************
 *                                                                            *
 *  FUNCTION   : lread(int fh, VOID FAR *pv, DWORD ul)                            *
 *                                                                            *
 *  PURPOSE    : Reads data in steps of 32k till all the data has been read.*
 *                                                                            *
 *  RETURNS    : 0 - If read did not proceed correctly.                     *
 *                 number of bytes read otherwise.                            *
 *                                                                            *
 ****************************************************************************/

static DWORD PASCAL lread(int fh, void far *pv, DWORD ul)
{
        DWORD     ulT = ul;
#if defined(WINNT) || defined(__WIN32__) || defined(__WIN32__) || defined(__WXWINE__)
        BYTE *hp = (BYTE *) pv;
#else
        BYTE huge *hp = (BYTE huge *) pv;
#endif
        while (ul > (DWORD) MAXREAD) {
                if (_lread(fh, (LPSTR) hp, (WORD) MAXREAD) != MAXREAD)
                        return 0;
                ul -= MAXREAD;
                hp += MAXREAD;
                }
        if (_lread(fh, (LPSTR) hp, (WORD) ul) != (WORD) ul)
                return 0;
        return ulT;
}

/****************************************************************************
 *                                                                            *
 *  FUNCTION   : lwrite(int fh, VOID FAR *pv, DWORD ul)                     *
 *                                                                            *
 *  PURPOSE    : Writes data in steps of 32k till all the data is written.  *
 *                                                                            *
 *  RETURNS    : 0 - If write did not proceed correctly.                    *
 *                 number of bytes written otherwise.                            *
 *                                                                            *
 ****************************************************************************/

static DWORD PASCAL lwrite(int fh, VOID FAR *pv, DWORD ul)
{
        DWORD     ulT = ul;
#if defined(WINNT) || defined(__WIN32__) || defined(__WIN32__) || defined(__WXWINE__)
        BYTE *hp = (BYTE *) pv;
#else
        BYTE huge *hp = (BYTE huge *) pv;
#endif
        while (ul > MAXREAD) {
                if (_lwrite(fh, (LPSTR) hp, (WORD) MAXREAD) != MAXREAD)
                        return 0;
                ul -= MAXREAD;
                hp += MAXREAD;
                }
        if (_lwrite(fh, (LPSTR) hp, (WORD) ul) != (WORD) ul)
                return 0;
        return ulT;
}

/****************************************************************************
 *
 *  FUNCTION   : ReadDIB(hWnd)
 *
 *  PURPOSE    : Reads a DIB from a file, obtains a handle to its
 *                 BITMAPINFO struct. and loads the DIB.  Once the DIB
 *               is loaded, the function also creates a bitmap and
 *               palette out of the DIB for a device-dependent form.
 *
 *  RETURNS    : TRUE  - DIB loaded and bitmap/palette created
 *                       The DIBINIT structure pointed to by pInfo is
 *                       filled with the appropriate handles.
 *                 FALSE - otherwise
 *
 ****************************************************************************/
BOOL wxReadDIB(LPTSTR lpFileName, HBITMAP *bitmap, HPALETTE *palette)
{
    int fh;
    LPBITMAPINFOHEADER lpbi;
    OFSTRUCT               of;
    BITMAPFILEHEADER   bf;
    WORD                nNumColors;
    BOOL result = FALSE;
    WORD offBits;
    HDC hDC;
    BOOL bCoreHead = FALSE;
    HANDLE hDIB = 0;

    /* Open the file and get a handle to it's BITMAPINFO */

    fh = OpenFile (wxFNCONV(lpFileName), &of, OF_READ);
    if (fh == -1) {
        wxLogError(_("Can't open file '%s'"), lpFileName);
        return (0);
    }

    hDIB = GlobalAlloc(GHND, (DWORD)(sizeof(BITMAPINFOHEADER) +
                                            256 * sizeof(RGBQUAD)));
    if (!hDIB)
        return(0);

#ifdef __WINDOWS_386__
    lpbi = (LPBITMAPINFOHEADER)MK_FP32(GlobalLock(hDIB));
#else
    lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDIB);
#endif

    /* read the BITMAPFILEHEADER */
    if (sizeof (bf) != _lread (fh, (LPSTR)&bf, sizeof (bf)))
        goto ErrExit;

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

    if (sizeof(BITMAPCOREHEADER) != _lread (fh, (LPSTR)lpbi, sizeof(BITMAPCOREHEADER)))
        goto ErrExit;

    if (lpbi->biSize == sizeof(BITMAPCOREHEADER))
    {
        lpbi->biSize = sizeof(BITMAPINFOHEADER);
        lpbi->biBitCount = ((LPBITMAPCOREHEADER)lpbi)->bcBitCount;
        lpbi->biPlanes = ((LPBITMAPCOREHEADER)lpbi)->bcPlanes;
        lpbi->biHeight = ((LPBITMAPCOREHEADER)lpbi)->bcHeight;
        lpbi->biWidth = ((LPBITMAPCOREHEADER)lpbi)->bcWidth;
        bCoreHead = TRUE;
    }
    else
    {
            // get to the start of the header and read INFOHEADER
        _llseek(fh,sizeof(BITMAPFILEHEADER),SEEK_SET);
        if (sizeof(BITMAPINFOHEADER) != _lread (fh, (LPSTR)lpbi, sizeof(BITMAPINFOHEADER)))
            goto ErrExit;
    }

    nNumColors = (WORD)lpbi->biClrUsed;
    if ( nNumColors == 0 )
    {
        /* 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);
    hDIB = GlobalReAlloc(hDIB, lpbi->biSize +
                                            nNumColors * sizeof(RGBQUAD) +
                                        lpbi->biSizeImage, 0);
    if (!hDIB)        /* can't resize buffer for loading */
        goto ErrExit2;

#ifdef __WINDOWS_386__
    lpbi = (LPBITMAPINFOHEADER)MK_FP32(GlobalLock(hDIB));
#else
    lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDIB);
#endif

    /* read the color table */
    if (!bCoreHead)
        _lread(fh, (LPSTR)(lpbi) + lpbi->biSize, nNumColors * sizeof(RGBQUAD));
    else
    {
        signed int i;
        RGBQUAD FAR *pQuad;
        RGBTRIPLE FAR *pTriple;

        _lread(fh, (LPSTR)(lpbi) + lpbi->biSize, nNumColors * sizeof(RGBTRIPLE));

        pQuad = (RGBQUAD FAR *)((LPSTR)lpbi + lpbi->biSize);
        pTriple = (RGBTRIPLE FAR *) pQuad;
        for (i = nNumColors - 1; i >= 0; i--)
        {
            pQuad[i].rgbRed = pTriple[i].rgbtRed;
            pQuad[i].rgbBlue = pTriple[i].rgbtBlue;
            pQuad[i].rgbGreen = pTriple[i].rgbtGreen;
            pQuad[i].rgbReserved = 0;
        }
    }

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

    if (bf.bfOffBits != 0L)
    {
        _llseek(fh,bf.bfOffBits,SEEK_SET);
    }

    if (lpbi->biSizeImage == lread(fh, (LPSTR)lpbi + offBits, lpbi->biSizeImage))
    {
        GlobalUnlock(hDIB);

        hDC = GetDC(NULL);
        if (!MakeBitmapAndPalette(hDC, hDIB, palette,
                                        bitmap))
        {
            ReleaseDC(NULL,hDC);
            goto ErrExit2;
        }
        else
        {
            ReleaseDC(NULL,hDC);
            GlobalFree(hDIB);
            result = TRUE;
        }
    }
    else
    {
ErrExit:
        GlobalUnlock(hDIB);
ErrExit2:
        GlobalFree(hDIB);
    }

    _lclose(fh);
    return(result);
}

/****************************************************************************
 *
 *  FUNCTION   : MakeBitmapAndPalette
 *
 *  PURPOSE    : Given a DIB, creates a bitmap and corresponding palette
 *               to be used for a device-dependent representation of
 *               of the image.
 *
 *  RETURNS    : TRUE  --> success. phPal and phBitmap are filled with
 *                         appropriate handles.  Caller is responsible
 *                         for freeing objects.
 *               FALSE --> unable to create objects.  both pointer are
 *                         not valid
 *
 ****************************************************************************/
static BOOL PASCAL MakeBitmapAndPalette(HDC hDC, HANDLE hDIB,
                        HPALETTE * phPal, HBITMAP * phBitmap)
{
    LPBITMAPINFOHEADER lpInfo;
    BOOL result = FALSE;
    HBITMAP hBitmap;
    HPALETTE hPalette, hOldPal;
    LPSTR lpBits;

#ifdef __WINDOWS_386__
    lpInfo = (LPBITMAPINFOHEADER) MK_FP32(GlobalLock(hDIB));
#else
    lpInfo = (LPBITMAPINFOHEADER) GlobalLock(hDIB);
#endif

    hPalette = wxMakeDIBPalette(lpInfo);
    if ( hPalette )
    {
        // Need to realize palette for converting DIB to bitmap.
        hOldPal = SelectPalette(hDC, hPalette, TRUE);
        RealizePalette(hDC);

        lpBits = (LPSTR)lpInfo + (WORD)lpInfo->biSize +
                (WORD)lpInfo->biClrUsed * sizeof(RGBQUAD);
        hBitmap = CreateDIBitmap(hDC, lpInfo, CBM_INIT, lpBits,
                                (LPBITMAPINFO)lpInfo, DIB_RGB_COLORS);

        SelectPalette(hDC, hOldPal, TRUE);
        RealizePalette(hDC);

        if (!hBitmap)
            DeleteObject(hPalette);
        else
        {
            *phBitmap = hBitmap;
            *phPal = hPalette;
            result = TRUE;
        }
    }
    return(result);
}

/****************************************************************************
 *                                                                            *
 *  FUNCTION   : wxMakeDIBPalette(lpInfo)                                            *
 *                                                                            *
 *  PURPOSE    : Given a BITMAPINFOHEADER, create a palette based on
 *                 the color table.
 *
 *                                                                            *
 *  RETURNS    : non-zero - handle of a corresponding palette
 *                 zero - unable to create palette
 *                                                                            *
 ****************************************************************************/
HPALETTE wxMakeDIBPalette(LPBITMAPINFOHEADER lpInfo)
{
#ifdef __WXWINE__
        return (FALSE);
#else
    LPLOGPALETTE npPal;
    RGBQUAD far *lpRGB;
    HPALETTE hLogPal;
    WORD i;

    /* since biClrUsed field was filled during the loading of the DIB,
    ** we know it contains the number of colors in the color table.
    */
    if (lpInfo->biClrUsed)
    {
/*
        npPal = (NPLOGPALETTE)LocalAlloc(LMEM_FIXED, sizeof(LOGPALETTE) +
                                (WORD)lpInfo->biClrUsed * sizeof(PALETTEENTRY));
*/
        npPal = (LPLOGPALETTE)malloc(sizeof(LOGPALETTE) +
                                (WORD)lpInfo->biClrUsed * sizeof(PALETTEENTRY));
        if (!npPal)
            return(FALSE);

        npPal->palVersion = 0x300;
        npPal->palNumEntries = (WORD)lpInfo->biClrUsed;

        /* get pointer to the color table */
        lpRGB = (RGBQUAD FAR *)((LPSTR)lpInfo + lpInfo->biSize);

        /* copy colors from the color table to the LogPalette structure */
        for (i = 0; i < lpInfo->biClrUsed; i++, lpRGB++)
        {
            npPal->palPalEntry[i].peRed = lpRGB->rgbRed;
            npPal->palPalEntry[i].peGreen = lpRGB->rgbGreen;
            npPal->palPalEntry[i].peBlue = lpRGB->rgbBlue;
            npPal->palPalEntry[i].peFlags = 0;
        }

        hLogPal = CreatePalette((LPLOGPALETTE)npPal);
//        LocalFree((HANDLE)npPal);
        free(npPal);

        return(hLogPal);
    }

    /* 24-bit DIB with no color table.  return default palette.  Another
    ** option would be to create a 256 color "rainbow" palette to provide
    ** some good color choices.
    */
    else
        return((HPALETTE) GetStockObject(DEFAULT_PALETTE));
#endif

}

bool wxLoadIntoBitmap(wxChar *filename, wxBitmap *bitmap, wxPalette **pal)
{
  HBITMAP hBitmap;
  HPALETTE hPalette;

  bool success = (wxReadDIB(filename, &hBitmap, &hPalette) != 0);

  if (!success)
  {
    DeleteObject(hPalette);
    return FALSE;
  }

  if (hPalette)
  {
    if (pal)
    {
      *pal = new wxPalette;
      (*pal)->SetHPALETTE((WXHPALETTE) hPalette);
    }
    else
      DeleteObject(hPalette);
  }
  else if (pal)
    *pal = NULL;

  if (hBitmap)
  {
    BITMAP bm;
    GetObject(hBitmap, sizeof(bm), (LPSTR)&bm);

    bitmap->SetHBITMAP((WXHBITMAP) hBitmap);
    bitmap->SetWidth(bm.bmWidth);
    bitmap->SetHeight(bm.bmHeight);
    bitmap->SetDepth(bm.bmPlanes * bm.bmBitsPixel);
#if WXWIN_COMPATIBILITY_2
    bitmap->SetOk(TRUE);
#endif // WXWIN_COMPATIBILITY_2
    return TRUE;
  }
  else return FALSE;
}

wxBitmap *wxLoadBitmap(wxChar *filename, wxPalette **pal)
{
  wxBitmap *bitmap = new wxBitmap;
  if (wxLoadIntoBitmap(filename, bitmap, pal))
    return bitmap;
  else
  {
    delete bitmap;
    return NULL;
  }
}

//---------------------------------------------------------------------
//
// Function:   InitBitmapInfoHeader
//
// Purpose:    Does a "standard" initialization of a BITMAPINFOHEADER,
//             given the Width, Height, and Bits per Pixel for the
//             DIB.
//
//             By standard, I mean that all the relevant fields are set
//             to the specified values.  biSizeImage is computed, the
//             biCompression field is set to "no compression," and all
//             other fields are 0.
//
//             Note that DIBs only allow BitsPixel values of 1, 4, 8, or
//             24.  This routine makes sure that one of these values is
//             used (whichever is most appropriate for the specified
//             nBPP).
//
// Parms:      lpBmInfoHdr == Far pointer to a BITMAPINFOHEADER structure
//                            to be filled in.
//             dwWidth     == Width of DIB (not in Win 3.0 & 3.1, high
//                            word MUST be 0).
//             dwHeight    == Height of DIB (not in Win 3.0 & 3.1, high
//                            word MUST be 0).
//             nBPP        == Bits per Pixel for the DIB.
//
// History:   Date      Reason
//            11/07/91  Created
//
//---------------------------------------------------------------------

static void InitBitmapInfoHeader (LPBITMAPINFOHEADER lpBmInfoHdr,
                                        DWORD dwWidth,
                                        DWORD dwHeight,
                                          int nBPP)
{
//   _fmemset (lpBmInfoHdr, 0, sizeof (BITMAPINFOHEADER));
   memset (lpBmInfoHdr, 0, sizeof (BITMAPINFOHEADER));

   lpBmInfoHdr->biSize      = sizeof (BITMAPINFOHEADER);
   lpBmInfoHdr->biWidth     = dwWidth;
   lpBmInfoHdr->biHeight    = dwHeight;
   lpBmInfoHdr->biPlanes    = 1;

   if (nBPP <= 1)
      nBPP = 1;
   else if (nBPP <= 4)
      nBPP = 4;
   else if (nBPP <= 8)
      nBPP = 8;
/* Doesn't work
   else if (nBPP <= 16)
      nBPP = 16;
*/
   else
      nBPP = 24;

   lpBmInfoHdr->biBitCount  = nBPP;
   lpBmInfoHdr->biSizeImage = WIDTHBYTES (dwWidth * nBPP) * dwHeight;
}




LPSTR wxFindDIBBits (LPSTR lpbi)
{
   return (lpbi + *(LPDWORD)lpbi + wxPaletteSize (lpbi));
}

//---------------------------------------------------------------------
//
// Function:   BitmapToDIB
//
// Purpose:    Given a device dependent bitmap and a palette, returns
//             a handle to global memory with a DIB spec in it.  The
//             DIB is rendered using the colors of the palette passed in.
//
//             Stolen almost verbatim from ShowDIB.
//
// Parms:      hBitmap == Handle to device dependent bitmap compatible
//                        with default screen display device.
//             hPal    == Palette to render the DDB with.  If it's NULL,
//                        use the default palette.
//
// History:   Date      Reason
//             6/01/91  Created
//
//---------------------------------------------------------------------

HANDLE wxBitmapToDIB (HBITMAP hBitmap, HPALETTE hPal)
{
   BITMAP             Bitmap;
   BITMAPINFOHEADER   bmInfoHdr;
   LPBITMAPINFOHEADER lpbmInfoHdr;
   LPSTR              lpBits;
   HDC                hMemDC;
   HANDLE             hDIB;
   HPALETTE           hOldPal = NULL;

      // Do some setup -- make sure the Bitmap passed in is valid,
      //  get info on the bitmap (like its height, width, etc.),
      //  then setup a BITMAPINFOHEADER.

   if (!hBitmap)
      return NULL;

   if (!GetObject (hBitmap, sizeof (Bitmap), (LPSTR) &Bitmap))
      return NULL;

   InitBitmapInfoHeader (&bmInfoHdr,
                         Bitmap.bmWidth,
                         Bitmap.bmHeight,
                         Bitmap.bmPlanes * Bitmap.bmBitsPixel);


      // Now allocate memory for the DIB.  Then, set the BITMAPINFOHEADER
      //  into this memory, and find out where the bitmap bits go.

   hDIB = GlobalAlloc (GHND, sizeof (BITMAPINFOHEADER) +
             wxPaletteSize ((LPSTR) &bmInfoHdr) + bmInfoHdr.biSizeImage);

   if (!hDIB)
      return NULL;

#ifdef __WINDOWS_386__
   lpbmInfoHdr  = (LPBITMAPINFOHEADER) MK_FP32(GlobalLock (hDIB));
#else
   lpbmInfoHdr  = (LPBITMAPINFOHEADER) GlobalLock (hDIB);
#endif

   *lpbmInfoHdr = bmInfoHdr;
   lpBits       = wxFindDIBBits ((LPSTR) lpbmInfoHdr);


      // Now, we need a DC to hold our bitmap.  If the app passed us
      //  a palette, it should be selected into the DC.

   hMemDC       = GetDC (NULL);

   if (hPal)
      {
      hOldPal = SelectPalette (hMemDC, hPal, FALSE);
      RealizePalette (hMemDC);
      }



      // We're finally ready to get the DIB.  Call the driver and let
      //  it party on our bitmap.  It will fill in the color table,
      //  and bitmap bits of our global memory block.

   if (!GetDIBits (hMemDC,
                   hBitmap,
                   0,
                   Bitmap.bmHeight,
                   lpBits,
                   (LPBITMAPINFO) lpbmInfoHdr,
                   DIB_RGB_COLORS))
      {
      GlobalUnlock (hDIB);
      GlobalFree (hDIB);
      hDIB = NULL;
      }
   else
      GlobalUnlock (hDIB);


      // Finally, clean up and return.

   if (hOldPal)
      SelectPalette (hMemDC, hOldPal, FALSE);

   ReleaseDC (NULL, hMemDC);

   return hDIB;
}

bool wxSaveBitmap(wxChar *filename, wxBitmap *bitmap, wxPalette *colourmap)
{
  HPALETTE hPalette = 0;
  if (colourmap)
    hPalette = (HPALETTE) colourmap->GetHPALETTE();

  HANDLE dibHandle = wxBitmapToDIB((HBITMAP) bitmap->GetHBITMAP(), hPalette);
  if (dibHandle)
  {
    bool success = (WriteDIB(filename, dibHandle) != 0);
    GlobalFree(dibHandle);
    return success;
  }
  else return FALSE;
}