dibutil.c

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//**********************************************************************
//
//  dibutil.c
//
//  Source file for Device-Independent Bitmap (DIB) API.  Provides
//  the following functions:
//
//  CreateDIB()         - Creates new DIB
//  FindDIBBits()       - Sets pointer to the DIB bits
//  DIBWidth()          - Gets the width of the DIB
//  DIBHeight()         - Gets the height of the DIB
//  PaletteSize()       - Calculates the buffer size required by a palette
//  DIBNumColors()      - Calculates number of colors in the DIB's color table
//  CreateDIBPalette()  - Creates a palette from a DIB
//  DIBToBitmap()       - Creates a bitmap from a DIB
//  BitmapToDIB()       - Creates a DIB from a bitmap
//  PalEntriesOnDevice()- Gets the number of palette entries of a device
//  GetSystemPalette()  - Returns a handle to the current system palette
//  AllocRoomForDIB()   - Allocates memory for a DIB
//  ChangeDIBFormat()   - Changes a DIB's BPP and/or compression format
//  ChangeBitmapFormat()- Changes a bitmap to a DIB with specified BPP and
//                        compression format
//
// Development Team: Mark Bader
//                   Patrick Schreiber
//                   Garrett McAuliffe
//                   Eric Flo
//                   Tony Claflin
//
// Written by Microsoft Product Support Services, Developer Support.
// COPYRIGHT:
//
//   (C) Copyright Microsoft Corp. 1993.  All rights reserved.
//
//   You have a royalty-free right to use, modify, reproduce and
//   distribute the Sample Files (and/or any modified version) in
//   any way you find useful, provided that you agree that
//   Microsoft has no warranty obligations or liability for any
//   Sample Application Files which are modified.
//
//**********************************************************************

/* header files */
#include <windows.h>
#include <assert.h>
#include "dibapi.h"
#include "dibutil.h"
#include <stdio.h>


/*************************************************************************
 *
 * 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 FAR 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 = (VOID FAR *)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 FAR 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 FAR 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 FAR 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 FAR 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 FAR 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 FAR 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 = 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)
   {