dib.cpp

一个完整的编辑器的代码（很值得参考

/////////////////////////////////////////////////////////////////////////////
// Copyright (C) 1998 by Jorge Lodos
// All rights reserved
//
// Distribute and use freely, except:
// 1. Don't alter or remove this notice.
// 2. Mark the changes you made
//
// Send bug reports, bug fixes, enhancements, requests, etc. to:
//    [e-mail]
/////////////////////////////////////////////////////////////////////////////

//  dib.cpp
//

#include "stdafx.h"
#include "dib.h"
#include <windowsx.h>
#include <afxadv.h>
#include <io.h>
#include <errno.h>

/////////////////////////////////////////////////////////////////////////////
// CDib

IMPLEMENT_DYNAMIC(CDib, CObject)

CDib::CDib()
{
	m_pBMI = NULL;
	m_pBits = NULL;
	m_pPalette = NULL;
}

CDib::~CDib()
{
	Free();
}

void CDib::Free()
{
	// Make sure all member data that might have been allocated is freed.
	if (m_pBits)
	{
		GlobalFreePtr(m_pBits);
		m_pBits = NULL;
	}
	if (m_pBMI)
	{
		GlobalFreePtr(m_pBMI);
		m_pBMI = NULL;
	}
	if (m_pPalette)
	{
		m_pPalette->DeleteObject();
		delete m_pPalette;
		m_pPalette = NULL;
	}
}

/*************************************************************************
 *
 * Paint()
 *
 * Parameters:
 *
 * HDC hDC          - DC to do output to
 *
 * LPRECT lpDCRect  - rectangle on DC to do output to
 *
 * LPRECT lpDIBRect - rectangle of DIB to output into lpDCRect
 *
 * CPalette* pPal   - pointer to CPalette containing DIB's palette
 *
 * Return Value:
 *
 * BOOL             - TRUE if DIB was drawn, FALSE otherwise
 *
 * Description:
 *   Painting routine for a DIB.  Calls StretchDIBits() or
 *   SetDIBitsToDevice() to paint the DIB.  The DIB is
 *   output to the specified DC, at the coordinates given
 *   in lpDCRect.  The area of the DIB to be output is
 *   given by lpDIBRect.
 *
 ************************************************************************/

BOOL CDib::Paint(HDC hDC, LPRECT lpDCRect, LPRECT lpDIBRect) const
{
	if (!m_pBMI)
		return FALSE;

	HPALETTE hPal = NULL;           // Our DIB's palette
	HPALETTE hOldPal = NULL;        // Previous palette

	// Get the DIB's palette, then select it into DC
	if (m_pPalette != NULL)
	{
		hPal = (HPALETTE) m_pPalette->m_hObject;

		// Select as background since we have
		// already realized in forground if needed
		hOldPal = ::SelectPalette(hDC, hPal, TRUE);
	}

	/* Make sure to use the stretching mode best for color pictures */
	::SetStretchBltMode(hDC, COLORONCOLOR);

	/* Determine whether to call StretchDIBits() or SetDIBitsToDevice() */
	BOOL bSuccess;
	if ((RECTWIDTH(lpDCRect)  == RECTWIDTH(lpDIBRect)) &&
	   (RECTHEIGHT(lpDCRect) == RECTHEIGHT(lpDIBRect)))
		bSuccess = ::SetDIBitsToDevice(hDC,        // hDC
								   lpDCRect->left,             // DestX
								   lpDCRect->top,              // DestY
								   RECTWIDTH(lpDCRect),        // nDestWidth
								   RECTHEIGHT(lpDCRect),       // nDestHeight
								   lpDIBRect->left,            // SrcX
								   (int)Height() -
									  lpDIBRect->top -
									  RECTHEIGHT(lpDIBRect),     // SrcY
								   0,                          // nStartScan
								   (WORD)Height(),             // nNumScans
								   m_pBits,                    // lpBits
								   m_pBMI,                     // lpBitsInfo
								   DIB_RGB_COLORS);            // wUsage
   else
	  bSuccess = ::StretchDIBits(hDC,            // hDC
							   lpDCRect->left,               // DestX
							   lpDCRect->top,                // DestY
							   RECTWIDTH(lpDCRect),          // nDestWidth
							   RECTHEIGHT(lpDCRect),         // nDestHeight
							   lpDIBRect->left,              // SrcX
							   lpDIBRect->top,               // SrcY
							   RECTWIDTH(lpDIBRect),         // wSrcWidth
							   RECTHEIGHT(lpDIBRect),        // wSrcHeight
							   m_pBits,                      // lpBits
							   m_pBMI,                       // lpBitsInfo
							   DIB_RGB_COLORS,               // wUsage
							   SRCCOPY);                     // dwROP

	/* Reselect old palette */
	if (hOldPal != NULL)
	{
		::SelectPalette(hDC, hOldPal, TRUE);
	}

   return bSuccess;
}

/*************************************************************************
 *
 * CreatePalette()
 *
 * Return Value:
 *
 * TRUE if succesfull, FALSE otherwise
 *
 * 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).
 *
 ************************************************************************/

BOOL CDib::CreatePalette()
{
	if (!m_pBMI)
		return FALSE;

   //get the number of colors in the DIB
   WORD wNumColors = NumColors();

   if (wNumColors != 0)
   {
		// allocate memory block for logical palette
		HANDLE hLogPal = ::GlobalAlloc(GHND, sizeof(LOGPALETTE) + sizeof(PALETTEENTRY)*wNumColors);

		// if not enough memory, clean up and return NULL
		if (hLogPal == 0)
			return FALSE;

		LPLOGPALETTE lpPal = (LPLOGPALETTE)::GlobalLock((HGLOBAL)hLogPal);

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

		for (int i = 0; i < (int)wNumColors; i++)
		{
			lpPal->palPalEntry[i].peRed = m_pBMI->bmiColors[i].rgbRed;
			lpPal->palPalEntry[i].peGreen = m_pBMI->bmiColors[i].rgbGreen;
			lpPal->palPalEntry[i].peBlue = m_pBMI->bmiColors[i].rgbBlue;
			lpPal->palPalEntry[i].peFlags = 0;
		}

		/* create the palette and get handle to it */
		if (m_pPalette)
		{
			m_pPalette->DeleteObject();
			delete m_pPalette;
		}
		m_pPalette = new CPalette;
		BOOL bResult = m_pPalette->CreatePalette(lpPal);
		::GlobalUnlock((HGLOBAL) hLogPal);
		::GlobalFree((HGLOBAL) hLogPal);
		return bResult;
	}

	return TRUE;
}

/*************************************************************************
 *
 * Width()
 *
 * Return Value:
 *
 * DWORD            - width of the DIB
 *
 * Description:
 *
 * This function gets the width of the DIB from the BITMAPINFOHEADER
 * width field 
 *
 ************************************************************************/

DWORD CDib::Width() const
{
	if (!m_pBMI)
		return 0;

	/* return the DIB width */
	return m_pBMI->bmiHeader.biWidth;
}


/*************************************************************************
 *
 * Height()
 *
 * Return Value:
 *
 * DWORD            - height of the DIB
 *
 * Description:
 *
 * This function gets the height of the DIB from the BITMAPINFOHEADER
 * height field 
 *
 ************************************************************************/

DWORD CDib::Height() const
{
	if (!m_pBMI)
		return 0;
	
	/* return the DIB height */
	return m_pBMI->bmiHeader.biHeight;
}


/*************************************************************************
 *
 * PaletteSize()
 *
 * 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 
 *
 ************************************************************************/

WORD CDib::PaletteSize() const
{
	if (!m_pBMI)
		return 0;

	return NumColors() * sizeof(RGBQUAD);
}


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