对于计算机图形学来说,位图的读写是一个非常重要方面,位图是计算机图形和图像的桥梁
在计算机图形处理中,着色后形成的图形就转变为图像,可以用成熟的图像处理算法来处理.
是真实感图形绘制的基础
对位图的处理主要是了解位图的数据结构,有了对位图的数据结构的了解后,其它的一切就
是一般的读写文件的方向,下面提供一个读写的类
#if !defined(AFX_FG_DIB_H__873E62A0_D6E8_4151_9F0F_815768446735__INCLUDED_)
#define AFX_FG_DIB_H__873E62A0_D6E8_4151_9F0F_815768446735__INCLUDED_
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
class CFG_DIB : public CObject
{
public:
//默认构造函数
CFG_DIB();
//构造函数,根据图象宽和高,以及记录每个象素所需字节数来初始化
CFG_DIB(int width, int height, int nBitCounts);
virtual ~CFG_DIB();
public:
HBITMAP m_hBitmap;
LPBYTE m_lpDIBits; //DIB位的起始位置
LPBITMAPINFOHEADER m_lpBMPHdr; //BITMAPINFOHEADER信息
LPVOID m_lpvColorTable; //颜色表信息
HPALETTE m_hPalette; //条调色板
private:
DWORD m_dwImageSize; //非BITMAPINFOHEADER或BITMAPFILEHEADER的位
int m_nColorEntries; //颜色表项的个数
//显示参数
public:
CPoint m_Dest; //目的矩形域的左上角坐标
CSize m_DestSize; //显示矩形的宽度和高度
CPoint m_Src; //原矩形左下角坐标
CSize m_SrcSize; //原矩形宽度和高度
public:
void InitDestroy(); //初始化变量
void ComputePaletteSize(int nBitCounts); //计算调色板大小
void ComputeImage(); //计算图象大小
//从BMP文件中读入DIB信息
BOOL ReadFile(CFile* pFile);
//从BMP文件中读入DIB信息,与ReadFile不同的是使用CreateSection创建位图位
BOOL ReadSection(CFile* pFile, CDC* pDC = NULL);
//将DIB写入文件，保存成BMP图片格式
BOOL WriteFile(CFile* pFile);
//创建新的位图文件，根据参数width,height,nBitCounts分配内存空间
BOOL NewFile(int width, int height, int nBitCounts);
//关闭位图文件
BOOL CloseFile();
//显示位图
BOOL Display(CDC* pDC);
HBITMAP CreateBitmap(CDC* pDC); //用DIB创建DDB
HBITMAP CreateSection(CDC* pDC = NULL); //创建位图位数据，即象素数据
//如果DIB没有颜色表，可以用逻辑调色板
BOOL SetLogPalette(CDC* pDC);
//如果DIB有颜色表，可以创建系统调色板
BOOL SetWinPalette();
//把DIB对象的逻辑调色板选进设备环境里，然后实现调色板
UINT UseLogPalette(CDC* pDC);
//得到BitmapInfoHeader的大小，包含颜色表数据
int GetHeaderSize()
{
return sizeof(BITMAPINFOHEADER) + sizeof(RGBQUAD) * m_nColorEntries;
}
//得到图像的高度
int GetHeight()
{
if(m_lpBMPHdr == NULL) return 0;
return m_lpBMPHdr->biHeight;
}
//得到图像的宽度
int GetWidth()
{
if(m_lpBMPHdr == NULL) return 0;
return m_lpBMPHdr->biWidth;
}
//得到图像的大小
int GetImageSize()
{
return m_dwImageSize;
}
long GetLineBit(); //得到一行的象素数
};
#endif // !defined(AFX_FG_DIB_H__873E62A0_D6E8_4151_9F0F_815768446735__INCLUDED_)
#include "stdafx.h"
#include "Dib.h"
#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif
//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////
CFG_DIB::CFG_DIB()
{
m_hBitmap = NULL;
m_hPalette = NULL;
m_Dest.x = 0;
m_Dest.y = 0;
m_DestSize.cx = 0;
m_DestSize.cy = 0;
m_Src.x = 0;
m_Src.y = 0;
m_SrcSize.cx = 0;
m_SrcSize.cy = 0;
InitDestroy();
}
CFG_DIB::CFG_DIB(int width, int height, int nBitCounts)
{
m_hBitmap = NULL;
m_hPalette = NULL;
m_Dest.x = 0;
m_Dest.y = 0;
m_DestSize.cx = 0;
m_DestSize.cy = 0;
m_Src.x = 0;
m_Src.y = 0;
m_SrcSize.cx = 0;
m_SrcSize.cy = 0;
InitDestroy();
ComputePaletteSize(nBitCounts); //为BITMAPINFOHEADER结构申请空间。
m_lpBMPHdr = (LPBITMAPINFOHEADER)new
char[sizeof(BITMAPINFOHEADER) + sizeof(RGBQUAD) * m_nColorEntries];
m_lpBMPHdr->biSize = sizeof(BITMAPINFOHEADER); //以下是为BITMAPINFOHEADER结构赋值
m_lpBMPHdr->biWidth = width;
m_lpBMPHdr->biHeight = height;
m_lpBMPHdr->biPlanes = 1;
m_lpBMPHdr->biBitCount = nBitCounts;
m_lpBMPHdr->biCompression = BI_RGB;
m_lpBMPHdr->biSizeImage = 0;
m_lpBMPHdr->biXPelsPerMeter = 0;
m_lpBMPHdr->biYPelsPerMeter = 0;
m_lpBMPHdr->biClrUsed = m_nColorEntries;
m_lpBMPHdr->biClrImportant = m_nColorEntries;
ComputeImage();
memset(m_lpvColorTable, 0, sizeof(RGBQUAD) * m_nColorEntries);
m_lpDIBits = NULL;
}
CFG_DIB::~CFG_DIB()
{
InitDestroy();
}
void CFG_DIB::InitDestroy()
{
m_Dest.x = 0;
m_Dest.y = 0;
m_DestSize.cx = 0;
m_DestSize.cy = 0;
m_Src.x = 0;
m_Src.y = 0;
m_SrcSize.cx = 0;
m_SrcSize.cy = 0;
if(m_hPalette != NULL) ::DeleteObject(m_hPalette);
if(m_hBitmap != NULL) ::DeleteObject(m_hBitmap);
m_lpBMPHdr = NULL;
m_lpDIBits = NULL;
m_lpvColorTable = NULL;
m_nColorEntries = 0;
m_dwImageSize = 0;
m_hBitmap = NULL;
m_hPalette = NULL;
}
void CFG_DIB::ComputePaletteSize(int nBitCounts)
{
if((m_lpBMPHdr == NULL) || (m_lpBMPHdr->biClrUsed == 0)) {
switch(nBitCounts) {
case 1:
m_nColorEntries = 2;
break;
case 4:
m_nColorEntries = 16;
break;
case 8:
m_nColorEntries = 256;
break;
case 16:
case 24:
case 32:
m_nColorEntries = 0;
break;
default:
ASSERT(FALSE);
}
}
else {
m_nColorEntries = m_lpBMPHdr->biClrUsed;
}
ASSERT((m_nColorEntries >= 0) && (m_nColorEntries <= 256));
}
void CFG_DIB::ComputeImage()
{
if(m_lpBMPHdr->biSize != sizeof(BITMAPINFOHEADER)) {
TRACE("Not a valid Windows bitmap -- probably an OS/2 bitmap\n");
throw new CException;
}
m_dwImageSize = m_lpBMPHdr->biSizeImage;
if(m_dwImageSize == 0) {
DWORD dwBytes = ((DWORD) m_lpBMPHdr->biWidth * m_lpBMPHdr->biBitCount) / 32;
if(((DWORD) m_lpBMPHdr->biWidth * m_lpBMPHdr->biBitCount) % 32) {
dwBytes++;
}
dwBytes *= 4;
//没被压缩
m_dwImageSize = dwBytes * m_lpBMPHdr->biHeight;
}
m_lpvColorTable = (LPBYTE) m_lpBMPHdr + sizeof(BITMAPINFOHEADER);
}
HBITMAP CFG_DIB::CreateBitmap(CDC* pDC)
{
if (m_dwImageSize == 0) return NULL;
HBITMAP hBitmap = ::CreateDIBitmap(pDC->GetSafeHdc(),
m_lpBMPHdr, CBM_INIT, m_lpDIBits,
(LPBITMAPINFO) m_lpBMPHdr, DIB_RGB_COLORS);
ASSERT(hBitmap != NULL);
return hBitmap;
}
HBITMAP CFG_DIB::CreateSection(CDC* pDC)
{
if(m_lpBMPHdr == NULL) return NULL;
if(m_lpDIBits != NULL) return NULL; //图像不存在
m_hBitmap = ::CreateDIBSection(pDC->GetSafeHdc(),
(LPBITMAPINFO)m_lpBMPHdr, DIB_RGB_COLORS,
(LPVOID*)&m_lpDIBits, NULL, 0);
ASSERT(m_lpDIBits != NULL);
return m_hBitmap;
}
BOOL CFG_DIB::SetWinPalette()
{
if(m_nColorEntries == 0) return FALSE;
if(m_hPalette != NULL) ::DeleteObject(m_hPalette);
TRACE("CDib::MakePalette -- m_nColorEntries = %d\n", m_nColorEntries);
LPLOGPALETTE pLogPal =
(LPLOGPALETTE) new char[2 * sizeof(WORD) +
m_nColorEntries * sizeof(PALETTEENTRY)];
pLogPal->palVersion = 0x300;
pLogPal->palNumEntries = m_nColorEntries;
LPRGBQUAD pDibRGBquad = (LPRGBQUAD) m_lpvColorTable;
for(int i = 0; i < m_nColorEntries; i++) {
pLogPal->palPalEntry[i].peRed =
pDibRGBquad->rgbRed;
pLogPal->palPalEntry[i].peGreen =
pDibRGBquad->rgbGreen;
pLogPal->palPalEntry[i].peBlue =
pDibRGBquad->rgbBlue;
pLogPal->palPalEntry[i].peFlags = 0;
pDibRGBquad++;
}
m_hPalette = ::CreatePalette(pLogPal);
delete pLogPal;
return TRUE;
}
BOOL CFG_DIB::SetLogPalette(CDC* pDC)
{
//如果DIB没有颜色表，可以用逻辑调色板
if(m_nColorEntries != 0) return FALSE;
m_hPalette = ::CreateHalftonePalette(pDC->GetSafeHdc());
return TRUE;
}
UINT CFG_DIB::UseLogPalette(CDC* pDC)
{
if(m_hPalette == NULL) return 0;
HDC hdc = pDC->GetSafeHdc();
::SelectPalette(hdc, m_hPalette,FALSE); //Windows作为前台调色板来实现该调色板
return ::RealizePalette(hdc);
}
BOOL CFG_DIB::NewFile(int width, int height, int nBitCounts)
{
if(m_hPalette != NULL) ::DeleteObject(m_hPalette);
if(m_hBitmap != NULL) ::DeleteObject(m_hBitmap);
m_hBitmap = NULL;
m_hPalette = NULL;
m_Dest.x = 0;
m_Dest.y = 0;
m_DestSize.cx = 0;
m_DestSize.cy = 0;
m_Src.x = 0;
m_Src.y = 0;
m_SrcSize.cx = 0;
m_SrcSize.cy = 0;
InitDestroy();
ComputePaletteSize(nBitCounts); //为BITMAPINFOHEADER结构申请空间。
m_lpBMPHdr = (LPBITMAPINFOHEADER)new
char[sizeof(BITMAPINFOHEADER) + sizeof(RGBQUAD) * m_nColorEntries];
m_lpBMPHdr->biSize = sizeof(BITMAPINFOHEADER); //以下是为BITMAPINFOHEADER结构赋值
m_lpBMPHdr->biWidth = width;
m_lpBMPHdr->biHeight = height;
m_lpBMPHdr->biPlanes = 1;
m_lpBMPHdr->biBitCount = nBitCounts;
m_lpBMPHdr->biCompression = BI_RGB;
m_lpBMPHdr->biSizeImage = 0;
m_lpBMPHdr->biXPelsPerMeter = 0;
m_lpBMPHdr->biYPelsPerMeter = 0;
m_lpBMPHdr->biClrUsed = m_nColorEntries;
m_lpBMPHdr->biClrImportant = m_nColorEntries;
ComputeImage();
memset(m_lpvColorTable, 0, sizeof(RGBQUAD) * m_nColorEntries);
m_lpDIBits = (LPBYTE) new char[m_dwImageSize];
memset(m_lpDIBits, 0, m_dwImageSize);
return TRUE;
}
BOOL CFG_DIB::CloseFile()
{
m_Dest.x = 0;
m_Dest.y = 0;
m_DestSize.cx = 0;
m_DestSize.cy = 0;
m_Src.x = 0;
m_Src.y = 0;
m_SrcSize.cx = 0;
m_SrcSize.cy = 0;
InitDestroy();
return TRUE;
}
BOOL CFG_DIB::WriteFile(CFile* pFile)
{
BITMAPFILEHEADER bmfh;
bmfh.bfType = 0x4d42; // 'BM'
int sizeHdr = sizeof(BITMAPINFOHEADER) +
sizeof(RGBQUAD) * m_nColorEntries;
bmfh.bfSize = 0;
bmfh.bfReserved1 = bmfh.bfReserved2 = 0;
bmfh.bfOffBits =
sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) +
sizeof(RGBQUAD) * m_nColorEntries;
try {
pFile->Write((LPVOID) &bmfh, sizeof(BITMAPFILEHEADER));
pFile->Write((LPVOID) m_lpBMPHdr, sizeHdr);
pFile->Write((LPVOID) m_lpDIBits, m_dwImageSize);
}
catch(CException* pe) {
pe->Delete();
AfxMessageBox("write error");
return FALSE;
}
return TRUE;
}
BOOL CFG_DIB::ReadFile(CFile* pFile)
{
InitDestroy();
int counts, size;
BITMAPFILEHEADER bmfh;
try {
counts = pFile->Read((LPVOID) &bmfh,
sizeof(BITMAPFILEHEADER));
if(counts != sizeof(BITMAPFILEHEADER)) {
throw new CException;
}
if(bmfh.bfType != 0x4d42) {
throw new CException;
}
size = bmfh.bfOffBits - sizeof(BITMAPFILEHEADER);
m_lpBMPHdr = (LPBITMAPINFOHEADER) new char[size];
// BITMAPINFOHEADER和颜色表
counts = pFile->Read(m_lpBMPHdr, size);
ComputeImage();
ComputePaletteSize(m_lpBMPHdr->biBitCount);
SetWinPalette();
m_lpDIBits = (LPBYTE) new char[m_dwImageSize];
counts = pFile->Read(m_lpDIBits, m_dwImageSize);
}
catch(CException* pe) {
AfxMessageBox("Read error");
pe->Delete();
return FALSE;
}
return TRUE;
}
BOOL CFG_DIB::ReadSection(CFile* pFile, CDC* pDC)
{
InitDestroy();
int counts, size;
BITMAPFILEHEADER bmfh;
try {
counts = pFile->Read((LPVOID) &bmfh,
sizeof(BITMAPFILEHEADER));
if(counts != sizeof(BITMAPFILEHEADER)) {
throw new CException;
}
if(bmfh.bfType != 0x4d42) {
throw new CException;
}
size = bmfh.bfOffBits - sizeof(BITMAPFILEHEADER);
m_lpBMPHdr = (LPBITMAPINFOHEADER) new char[size];
//BITMAPINFOHEADER和颜色表
counts = pFile->Read(m_lpBMPHdr, size);
if(m_lpBMPHdr->biCompression != BI_RGB) {
throw new CException;
}
ComputeImage();
ComputePaletteSize(m_lpBMPHdr->biBitCount);
SetWinPalette();
UseLogPalette(pDC);
m_hBitmap = ::CreateDIBSection(pDC->GetSafeHdc(),
(LPBITMAPINFO) m_lpBMPHdr, DIB_RGB_COLORS,
(LPVOID*) &m_lpDIBits, NULL, 0);
ASSERT(m_lpDIBits != NULL);
counts = pFile->Read(m_lpDIBits, m_dwImageSize); // 图像
}
catch(CException* pe) {
AfxMessageBox("ReadSection error");
pe->Delete();
return FALSE;
}
return TRUE;
}
BOOL CFG_DIB::Display(CDC* pDC)
{
if(m_lpBMPHdr == NULL) return FALSE;
if(m_hPalette != NULL) {
::SelectPalette(pDC->GetSafeHdc(), m_hPalette, TRUE);
}
::StretchDIBits(pDC->GetSafeHdc(), m_Dest.x, m_Dest.y,
m_DestSize.cx, m_DestSize.cy,
m_Src.x, m_Src.y,
m_SrcSize.cx, m_SrcSize.cy,
m_lpDIBits, (LPBITMAPINFO) m_lpBMPHdr,
DIB_RGB_COLORS, SRCCOPY);
return TRUE;
}
long CFG_DIB::GetLineBit()
{
long dwBytes = ((long)m_lpBMPHdr->biWidth * m_lpBMPHdr->biBitCount) / 32;
if(((long)m_lpBMPHdr->biWidth * m_lpBMPHdr->biBitCount) % 32)
{
dwBytes++;
}
dwBytes *= 4;
return dwBytes;
}
使用如下,可以在OnView()函数内使用
CFile* pf;
pf = new CFile;
pf->Open("D://uuuu.bmp", CFile::modeRead);
m_fgdib.ReadFile(pf);
pf->Close();
delete pf;
//draw BMP
m_fgdib.m_Dest.x = 0;
m_fgdib.m_Dest.y = 0;
m_fgdib.m_DestSize.cx = m_fgdib.GetWidth();
m_fgdib.m_DestSize.cy = m_fgdib.GetHeight();
m_fgdib.m_Src.x = 0;
m_fgdib.m_Src.y = 0;
m_fgdib.m_SrcSize.cx = m_fgdib.GetWidth();
m_fgdib.m_SrcSize.cy = m_fgdib.GetHeight();
//CDC* pDC = GetDC();
m_fgdib.Display(pDC);
//close BMP
m_fgdib.CloseFile();