dib.cpp

这是《深入浅出MFC》这本书的源代码

// DIB.cpp

#include "stdafx.h"
#include "DIB.h"

CDib::CDib()
{

	// Set the Dib pointer to
	// NULL so we know if it's
	// been loaded.
	m_pDib = NULL;

}

CDib::~CDib()
{

	// If a Dib has been loaded,
	// delete the memory.
	if( m_pDib != NULL )
		delete [] m_pDib;

}

BOOL CDib::Load( const char *pszFilename )
{

	CFile cf;

	// Attempt to open the Dib file for reading.
	if( !cf.Open( pszFilename, CFile::modeRead ) )
		return( FALSE );

	// Get the size of the file and store
	// in a local variable. Subtract the
	// size of the BITMAPFILEHEADER structure
	// since we won't keep that in memory.
	DWORD dwDibSize;
	dwDibSize =
		cf.GetLength() - sizeof( BITMAPFILEHEADER );

	// Attempt to allocate the Dib memory.
	unsigned char *pDib;
	pDib = new unsigned char [dwDibSize];
	if( pDib == NULL )
		return( FALSE );

	BITMAPFILEHEADER BFH;

	// Read in the Dib header and data.
	try{

		// Did we read in the entire BITMAPFILEHEADER?
		if( cf.Read( &BFH, sizeof( BITMAPFILEHEADER ) )
			!= sizeof( BITMAPFILEHEADER ) ||

			// Is the type 'MB'?
			BFH.bfType != 'MB' ||

			// Did we read in the remaining data?
			cf.Read( pDib, dwDibSize ) != dwDibSize ){

			// Delete the memory if we had any
			// errors and return FALSE.
			delete [] pDib;
			return( FALSE );
			}
		}

	// If we catch an exception, delete the
	// exception, the temporary Dib memory,
	// and return FALSE.
	catch( CFileException *e ){
		e->Delete();
		delete [] pDib;
		return( FALSE );
		}
	
	// If we got to this point, the Dib has been
	// loaded. If a Dib was already loaded into
	// this class, we must now delete it.
	if( m_pDib != NULL )
		delete m_pDib;

	// Store the local Dib data pointer and
	// Dib size variables in the class member
	// variables.
	m_pDib = pDib;
	m_dwDibSize = dwDibSize;

	// Pointer our BITMAPINFOHEADER and RGBQUAD
	// variables to the correct place in the Dib data.
	m_pBIH = (BITMAPINFOHEADER *) m_pDib;
	m_pPalette =
		(RGBQUAD *) &m_pDib[sizeof(BITMAPINFOHEADER)];

	// Calculate the number of palette entries.
	m_nPaletteEntries = 1 << m_pBIH->biBitCount;
	if( m_pBIH->biBitCount > 8 )
		m_nPaletteEntries = 0;
	else if( m_pBIH->biClrUsed != 0 )
		m_nPaletteEntries = m_pBIH->biClrUsed;

	// Point m_pDibBits to the actual Dib bits data.
	m_pDibBits =
		&m_pDib[sizeof(BITMAPINFOHEADER)+
			m_nPaletteEntries*sizeof(RGBQUAD)];

	// If we have a valid palette, delete it.
	if( m_Palette.GetSafeHandle() != NULL )
		m_Palette.DeleteObject();

	// If there are palette entries, we'll need
	// to create a LOGPALETTE then create the
	// CPalette palette.
	if( m_nPaletteEntries != 0 ){

		// Allocate the LOGPALETTE structure.
		LOGPALETTE *pLogPal = (LOGPALETTE *) new char
				[sizeof(LOGPALETTE)+
				m_nPaletteEntries*sizeof(PALETTEENTRY)];

		if( pLogPal != NULL ){

			// Set the LOGPALETTE to version 0x300
			// and store the number of palette
			// entries.
			pLogPal->palVersion = 0x300;
			pLogPal->palNumEntries = m_nPaletteEntries;

			// Store the RGB values into each
			// PALETTEENTRY element.
			for( int i=0; i<m_nPaletteEntries; i++ ){
				pLogPal->palPalEntry[i].peRed =
					m_pPalette[i].rgbRed;
				pLogPal->palPalEntry[i].peGreen =
					m_pPalette[i].rgbGreen;
				pLogPal->palPalEntry[i].peBlue =
					m_pPalette[i].rgbBlue;
				}

			// Create the CPalette object and
			// delete the LOGPALETTE memory.
			m_Palette.CreatePalette( pLogPal );
			delete [] pLogPal;
			}
		}
	
	return( TRUE );

}

BOOL CDib::Save( const char *pszFilename )
{

	// If we have no data, we can't save.
	if( m_pDib == NULL )
		return( FALSE );

	CFile cf;

	// Attempt to create the file.
	if( !cf.Open( pszFilename,
		CFile::modeCreate | CFile::modeWrite ) )
		return( FALSE );
	
	// Write the data.
	try{

		// First, create a BITMAPFILEHEADER
		// with the correct data.
		BITMAPFILEHEADER BFH;
		memset( &BFH, 0, sizeof( BITMAPFILEHEADER ) );
		BFH.bfType = 'MB';
		BFH.bfSize = sizeof( BITMAPFILEHEADER ) + m_dwDibSize;
		BFH.bfOffBits = sizeof( BITMAPFILEHEADER ) +
			sizeof( BITMAPINFOHEADER ) +
			m_nPaletteEntries * sizeof( RGBQUAD );

		// Write the BITMAPFILEHEADER and the
		// Dib data.
		cf.Write( &BFH, sizeof( BITMAPFILEHEADER ) );
		cf.Write( m_pDib, m_dwDibSize );
		}

	// If we get an exception, delete the exception and
	// return FALSE.
	catch( CFileException *e ){
		e->Delete();
		return( FALSE );
		}

	return( TRUE );

}

BOOL CDib::Draw( CDC *pDC, int nX, int nY, int nWidth, int nHeight, int mode  )
{

	// If we have not data we can't draw.
	if( m_pDib == NULL )
		return( FALSE );

	// Check for the default values of -1
	// in the width and height arguments. If
	// we find -1 in either, we'll set them
	// to the value that's in the BITMAPINFOHEADER.
	if( nWidth == -1 )
		nWidth = m_pBIH->biWidth;
	if( nHeight == -1 )
		nHeight = m_pBIH->biHeight;
	
	// Use StretchDIBits to draw the Dib.
	StretchDIBits( pDC->m_hDC, nX, nY,
		nWidth, nHeight,
		0, 0,
		m_pBIH->biWidth, m_pBIH->biHeight,
		m_pDibBits,
		(BITMAPINFO *) m_pBIH,
		BI_RGB, mode );
	
	return( TRUE );

}

BOOL CDib::SetPalette( CDC *pDC )
{

	// If we have not data we
	// won't want to set the palette.
	if( m_pDib == NULL )
		return( FALSE );

	// Check to see if we have a palette
	// handle. For Dibs greater than 8 bits,
	// this will be NULL.
	if( m_Palette.GetSafeHandle() == NULL )
		return( TRUE );

	// Select the palette, realize the palette,
	// then finally restore the old palette.
	CPalette *pOldPalette;
	pOldPalette = pDC->SelectPalette( &m_Palette, FALSE );
	pDC->RealizePalette();
	pDC->SelectPalette( pOldPalette, FALSE );

	return( TRUE );

}