// Dib.cpp: implementation of the CDib class.
//
//////////////////////////////////////////////////////////////////////

#include "StdAfx.h"
#include "Dib.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// C
//////////////////////////////////////////////////////////////////////
//構造與析構函數
CDib::CDib()
{
	m_hDrawDib=NULL;
	m_pDib=NULL;
}

CDib::~CDib()
{
	Close();
}
//在設備環境上繪制圖象
void CDib::Draw(CDC *pDC,int nWidth, int nHeight)
{
	if(m_pDib!=NULL)
	{
	ASSERT(IsValid());
	DrawDibRealize(m_hDrawDib,pDC->GetSafeHdc(),TRUE);
	//采用VFW組件繪圖
	DrawDibDraw(m_hDrawDib,pDC->GetSafeHdc(),
				0,  
				0,  
				nWidth,
				nHeight,
				(BITMAPINFOHEADER *)m_pDib,
				(LPVOID) GetBits(),
				0,  
				0,  
				((BITMAPINFOHEADER *)m_pDib)->biWidth,
				((BITMAPINFOHEADER *)m_pDib)->biHeight,
				DDF_BACKGROUNDPAL);
	}
}
//獲得位圖的CSize結構
CSize CDib::GetSize()
{
	return CSize(((BITMAPINFOHEADER *)m_pDib)->biWidth,
				 ((BITMAPINFOHEADER *)m_pDib)->biHeight);	
}
//獲得位圖的寬度
DWORD CDib::GetWidth()
{
	return ((BITMAPINFOHEADER *)m_pDib)->biWidth;
}
//獲得位圖每行的字節數
DWORD CDib::GetWidthBytes()
{
BITMAPINFOHEADER *lpDib=(BITMAPINFOHEADER *)m_pDib;
WORD wBitCount=lpDib->biBitCount;
WORD wWidth=lpDib->biWidth;
//WidthBytes=(((biWidth*biBitCount)+31)&~31)>>3
DWORD bytes_per_line=(((wWidth*wBitCount)+31)&~31)>>3;
return bytes_per_line;
}
//獲得位圖的高度
DWORD CDib::GetHeight()
{
	return	((BITMAPINFOHEADER *)m_pDib)->biHeight;
}
//釋放位圖資源
void CDib::Close()
{
	if(m_hDrawDib!=NULL)
	{
		DrawDibClose(m_hDrawDib);
		m_hDrawDib=NULL;
	}

	if(m_pDib!=NULL)
	{
		delete m_pDib;
		m_pDib=NULL;
		m_pDibBits=NULL;
	}
}
//將位圖文件中的位圖讀入內存中
BOOL CDib::Open(const char * pzFileName)
{
	CFile file;
	int nBmpFileHeaderSize;
	Close(); 
	//初始化DrawDib函數組
	if(!(m_hDrawDib=DrawDibOpen()))
		goto exit;

 	//打開位圖文件并讀取位圖的BITMAPFILEHEADER數據
	nBmpFileHeaderSize=sizeof(BITMAPFILEHEADER);

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

	if(file.Read((void *)&bmpFileHeader,nBmpFileHeaderSize)!=(UINT)nBmpFileHeaderSize)
		goto failure;

	//判斷位圖文件的有效性
	if(bmpFileHeader.bfType!=*((WORD *)"BM"))
		goto failure;

	//為位圖數據分配空間
	m_pDib=(BYTE *)new char [bmpFileHeader.bfSize-nBmpFileHeaderSize];

	if(!m_pDib)
		goto failure;

	//將位圖數據讀入到內存中
	file.ReadHuge(m_pDib,bmpFileHeader.bfSize-nBmpFileHeaderSize);

	if(((BITMAPINFOHEADER *)m_pDib)->biSizeImage==0)
	{
		
		BITMAPINFOHEADER *pDib=(BITMAPINFOHEADER *)m_pDib;

	//scan lines must be DWord aligned, hence the strange bit stuff
	pDib->biSizeImage=((((pDib->biWidth*pDib->biBitCount)+31)&~31)>>3)*pDib->biHeight;
	}

	m_pDibBits=GetBits();

	file.Close();
	return TRUE;

failure:
	file.Close();
exit:
	Close();
	return FALSE;
}
//保存位圖
BOOL CDib::Save(const char * pzFileName)
{

	CFile file;
	int nBmpFileHeaderSize;

	nBmpFileHeaderSize=sizeof(BITMAPFILEHEADER);

	if(!file.Open(pzFileName,CFile::modeCreate | CFile::modeWrite | CFile::typeBinary))
		goto exit;
     //將文件頭信息寫入
	file.Write(&bmpFileHeader,nBmpFileHeaderSize); 
	if(!m_pDib)
		goto failure;

	//將文件其它信息寫入
	file.WriteHuge(m_pDib,bmpFileHeader.bfSize-nBmpFileHeaderSize);

	file.Close();
	return TRUE;

failure:
	file.Close();
exit:
	return FALSE;
}
//獲得位圖數據的指針
BYTE * CDib::GetBits()
{
	
	DWORD dwNumColors,dwColorTableSize;
	BITMAPINFOHEADER *lpDib=(BITMAPINFOHEADER *)m_pDib;
	//獲取顏色數
	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;
}

DWORD CDib::GetBiBitCount()
{
	if(m_pDib!=NULL)
		return ((BITMAPINFOHEADER *)m_pDib)->biBitCount; 
	return 0;
}