dib.cpp

数据结构链表的演示程序

// Dib.cpp : implementation of the CDIB class
// written by Xu
////////////////////////////////////////////////

#include "stdafx.h"
#include "dib.h"

CDIB::CDIB()
{
	m_hDrawDib=NULL;
	m_pDIB=NULL;
	m_Colors=0;
}

CDIB::~CDIB()
{
	Close();
}

void CDIB:: Draw (CDC * pDC, int nWidth, int nHeight)
{
	ASSERT (IsValid());

	DrawDibRealize (m_hDrawDib, pDC->GetSafeHdc (), TRUE);

	DrawDibDraw (m_hDrawDib, pDC->GetSafeHdc (),
		0,			// dest left
		0,			// dest top
		nWidth,
		nHeight,
		(BITMAPINFOHEADER *) m_pDIB,
		(LPVOID) GetBits (),
		0,			// source left
		0,			// source top
		((BITMAPINFOHEADER * ) m_pDIB)->biWidth,
		((BITMAPINFOHEADER * ) m_pDIB)->biHeight,
		DDF_BACKGROUNDPAL);
}

CSize CDIB:: GetSize()
{
	return CSize (((BITMAPINFOHEADER *) m_pDIB) ->biWidth,
		((BITMAPINFOHEADER *) m_pDIB) ->biHeight);
}

void CDIB:: Close()
{
	if (m_hDrawDib != NULL)
	{
		DrawDibClose (m_hDrawDib);
		m_hDrawDib=NULL;
	}

	if (m_pDIB != NULL)
		delete m_pDIB;
}


BOOL CDIB:: Open (const char * pzFileName)
{
	BITMAPFILEHEADER bmpfh;
	CFile file;
	int nHeaderSize;
	int i;
	RGBQUAD quad;
	RGBQUAD *quads;
	BITMAPINFOHEADER * pDib;

	Close ();
	// DrawDibOpen initializes the DrawDib library and
	// return a handle for all DrawDib operations
	if (! (m_hDrawDib=DrawDibOpen ()))
		goto fail;
	
	// Open and read the DIB file header
	nHeaderSize=sizeof (BITMAPFILEHEADER);

	if (! file.Open (pzFileName, CFile:: modeRead | CFile:: typeBinary))
		goto fail;

	if (file.Read ( (void * ) &bmpfh, nHeaderSize) != (UINT) nHeaderSize)
		goto fail;

	// Validate the DIB file header by checking the first
	// two characters for the signature " BM "
	if (bmpfh.bfType != * ( (WORD *) "BM"))
		goto fail;
	
	FileSize=bmpfh.bfSize;
	// Allocate a big chunk of global memory to store the DIB
	m_pDIB= (BYTE *) new char [bmpfh.bfSize-nHeaderSize];
	if (! m_pDIB)
		goto fail;

	// Read the DIB into the buffer 32K at a time using ReadHuge
	file.ReadHuge (m_pDIB, bmpfh.bfSize-nHeaderSize);
	pDib= (BITMAPINFOHEADER *) m_pDIB;
	if ( ( (BITMAPINFOHEADER *) m_pDIB) ->biSizeImage==0)
	{
		// The application that created this bitmap didn't fill in
		// the biSizeImage field (Photoshop 3.0x does this) . Let's
		// fill it in even though the DrawDib * functions don't need it.
		// Scan lines must be DWORD aligned, hence the strange bit stuff
		pDib->biSizeImage=
			((((pDib->biWidth * pDib->biBitCount)+31)&~31)>>3) * pDib->biHeight;
	}

	m_nBitcount=pDib->biBitCount;

	if(pDib->biClrUsed!=0)
		m_Colors=pDib->biClrUsed;
	else if(pDib->biBitCount<=8)
		m_Colors=(1<<pDib->biBitCount);

	if(m_Colors>0&&m_Colors<=256)
	{// 填入调色板数组索引
		quads=(RGBQUAD*)(m_pDIB+sizeof(BITMAPINFOHEADER));
		m_Quads.SetSize(m_Colors,-1);
		for(i=0;i<m_Colors;i++)
		{
			quad.rgbRed=quads[i].rgbRed;
			quad.rgbGreen=quads[i].rgbGreen;
			quad.rgbBlue=quads[i].rgbBlue;
			m_Quads[i]=quad;
		}
	}
	file.Close ();
	return TRUE;

fail:
	Close ();
	return FALSE;
}


BYTE * CDIB:: GetBits ()
{
	// The size of the color map is determined by the number of
	// RGBQUAD structures present.	It also depends on the bit-depth
	// of the DIB.
	DWORD dwNumColors, dwColorTableSize;
	BITMAPINFOHEADER * lpDib= (BITMAPINFOHEADER *) m_pDIB;

	WORD wBitCount=lpDib->biBitCount;

	if (lpDib->biSize>=36)
		dwNumColors=lpDib->biClrUsed;
	else
		dwNumColors=0;

	if (dwNumColors==0)
	{
		if (wBitCount !=24)
			dwNumColors=1L<<wBitCount;
		else
			dwNumColors=0;
	}

	dwColorTableSize=dwNumColors * sizeof (RGBQUAD);

	return m_pDIB+lpDib->biSize+dwColorTableSize;
}