读取并显示一幅bmp图象编程流程.doc

一、BMP：包括BITMAPFILEHEADER(位图文件头)、BITMAPINFOHEADER(位图信息头)、Palette（调色板）、ImageData（位图数据）构成。DDB：是设备相关位图文件，结构如下：Typedef struct tagBITMAPInt bmType；/通常为0Int bmWidth；/像素点宽度Int bmHeight；/像素点高度Int bmWidthBytes；/每行数据的字节数，必为偶数BYTE bmPlanes；/显示设备的色位面数BYTE bmBitsPixel；/每像素的位数Void FAR *bmBits；/指向像素数据的指针；位图必须在同类设备中显示，并且此设备在位平面或彩色上与原设备有同样的色彩安排，否则色彩可能完全失真。DIB是设备无关位图文件，由3部分构成：BITMAPINFOHEADER(位图信息头)、Palette（调色板）、ImageData（位图数据）。它的结构和BMP文件结构相似，它实际就是BMP文件去掉BITMAPFILEHEADER（位图文件头），即一个BITMAPINFOHEADER（位图信息头）结构后面接上调色板再加上图像数据。BMP文件有两种显示方法，首先将BMP文件读成DIB格式，当显示时，一种是直接将DIB显示，另一种是将DIB转化为DDB，再显示DDB。几个数据类型：Cfile LPCTSTR UINT几个函数：1、virtual BOOL Open( LPCTSTR lpszFileName, UINT nOpenFlags, CFileException* pError = NULL );Return Value：Nonzero if the open was successful; otherwise 0. The pError parameter is meaningful only if 0 is returned.LpszFileName：A string that is the path to the desired file. NOpenFlags： defines the files sharing and access mode. It specifies the action to take when opening the file.PError：A pointer to an existing file-exception object that will receive the status of a failed operation.如：Open(filename,CFile:modeRead|CFile:shareDenyNone,NULL)=0) 2、int AfxMessageBox( LPCTSTR lpszText, UINT nType = MB_OK, UINT nIDHelp = 0 );3、The HeapAlloc function allocates a block of memory from a heap. The allocated memory is not movable. LPVOID HeapAlloc( HANDLE hHeap, / handle to the private heap block DWORD dwFlags, / heap allocation control flags DWORD dwBytes / number of bytes to allocate);4、memcpy：Copies characters between buffers5、HeapFree：frees a memory block allocated from a heap by the HeapAlloc or HeapReAlloc function. 6、SetDIBitsToDevice ：sets the pixels in the specified rectangle on the device that is associated with the destination device context using color data from a device-independent bitmap (DIB). int SetDIBitsToDevice( HDC hdc, / handle to device context int XDest, / x-coordinate of upper-left corner of / dest. rect. int YDest, / y-coordinate of upper-left corner of / dest. rect. DWORD dwWidth, / source rectangle width DWORD dwHeight, / source rectangle height int XSrc, / x-coordinate of lower-left corner of / source rect. int YSrc, / y-coordinate of lower-left corner of / source rect. UINT uStartScan, / first scan line in array UINT cScanLines, / number of scan lines CONST VOID *lpvBits, / address of array with DIB bits CONST BITMAPINFO *lpbmi, / address of structure with bitmap info. UINT fuColorUse / RGB or palette indexes);二、新建一多（单）文档应用程序Getbmp三、在*Doc.h中添加几个变量：BITMAPFILEHEADER bf;/文件头BITMAPINFOHEADER bi;/信息头RGBQUAD *quad; /调色板BYTE *lpBuf; /图像数据BITMAPINFO *pbi;int flag; /标志是否打开了bmp文件int numQuad; /调色板数目四、对C*Doc类添加消息处理函数：OnOpenDocument（）CString filename;CFile file;/打开文件对话框filename=lpszPathName;if (file.Open(filename,CFile:modeRead|CFile:shareDenyNone,NULL)=0)/读取文件失败AfxMessageBox(无法打开文件！,MB_OK,0);return 1;/读取文件头file.Read(&bf,sizeof(bf);if(bf.bfType!=0x4d42) /BMAfxMessageBox(非BMP文件！,MB_OK,0);return 1;/判断文件是否损坏if (file.GetLength()!=bf.bfSize)AfxMessageBox(文件已损坏，请检查！,MB_OK,0);return 1;/读取文件信息头file.Read(&bi,sizeof(bi);/计算调色板数目numQuad=0;if (bi.biBitCount24)numQuad=1flag=1)SetDIBitsToDevice(dc.m_hDC, /DIB将输出的设备描述表0, /设备描述表中位图输出起始逻辑x坐标0, /设备描述表中位图输出起始逻辑y坐标pDoc-bi.biWidth, /DIB的宽度pDoc-bi.biHeight, /DIB的高度0, /DIB开始读取输出的像素数据的x位置0, /DIB开始读取输出的像素数据的y位置0, /DIB中像素的水平行号，它对应lpBits内存缓冲区第一行数据pDoc-bi.biHeight, /DIB的行数，对应包含在由lpBits所指内存缓冲区中的数据pDoc-lpBuf, /包含像素数据的内存缓冲区的指针pDoc-pbi, /指向初始化了的BITMAPINFO数据结构的指针