Read pixel data from bitmap file

/* ===================================================== ========================================< Br/> * getbmp data. cpp <br/> * This mex-file is used to read pixel data from bmp file directly <br/> * from bitmap file. <br/> * This is a MEX-file for MATLAB. <br/> * Created by visionfans @ 2011.06.16 <br/> * ================== ========================================================== */<br/> # include <stdio. h> <br/> # include <string. h> <br/> # include <windows. h> <br/> # include "mex. h "<br/> BYTE Bit2Byte (BYTE * pData, int iRow, int iCol, int nRowWidth); <br/> void mexFunction (int nlhs, mxArray * plhs [], <br/> int nrhs, const mxArray * prhs []) <br/> {<br/> // read bmp file <br/> // <br/> char * bmp Path = mxArrayToString (prhs [0] ); <br/> FILE * pFile = fopen (BMP path, "rb"); <br/> if (pFile = NULL) {<br/> mexWarnMsgTxt ("Open File Error/n"); <br/>}< br/> // get file size <br/> fseek (pFile, 0L, SEEK_END); <br/> DWORD fileSize = ftell (pFile); <br/> // read the entire file <br/> BYTE * pData = new BYTE [fileSize]; <br/> ZeroMemory (pData, fileSize); <br/> fseek (pFile, 0L, SEEK_SET); <br/> fread (pData, 1, fileSize, pFile ); <br/> // get the image matrix from bmp file <br/> // <br/> BITMAPFILEHEADER Bfh; // file header <br/> LPBITMAPINFO lpBmi; // bitmap info <br/> int BmiSize; <br/> // get bmp image information <br/> // <br/> memcpy (& Bfh, pData, sizeof (BITMAPFILEHEADER )); <br/> BmiSize = Bfh. bfOffBits-sizeof (BITMAPFILEHEADER); <br/> lpBmi = (LPBITMAPINFO) malloc (BmiSize); <br/> memcpy (lpBmi, pData + sizeof (BITMAPFILEHEADER), BmiSize ); <br/> // get image data <br/> // <br/> int nWidth = lpBmi-> bmiHeader. biWidth; <br/> int nHeight = lpBmi-> bmiHeader. biHeight; <br/> int bits = lpBmi-> bmiHeader. biBitCount; <br/> // point to image data <br/> BYTE * pImgData = pData + Bfh. bfOffBits; <br/> // copy all bit data to byte data <br/> // <br/> BYTE * pOutData = (BYTE *) mxCalloc (nWidth * nHeight, sizeof (BYTE); <br/> // copy data <br/> int nRowWidth = (bits * nWidth + 31)> 5) <2; <br/> int arrayIdx = 0; <br/> for (int j = 0; j <nWidth; j ++) <br/> {<br/> for (int I = 0; I <nHeight; I ++) <br/> {<br/> pOutData [arrayIdx ++] = Bit2Byte (pImgData, I, j, nRowWidth ); <br/>}< br/> // <br/> // create output matrix and set data <br/> // <br/> int ndims = 2; <br/> int dims [] = {nHeight, nWidth}; <br/> plhs [0] = mxCreateNumericArray (ndims, dims, mxUINT8_CLASS, mxREAL ); <br/> mxSetData (plhs [0], pOutData); <br/> fclose (pFile); <br/> delete pData; <br/>}</p> <p> BYTE Bit2Byte (BYTE * pData, int iRow, int iCol, int nRowWidth) <br/>{< br/> BYTE byPixel = 0; <br/> // get byte index <br/> int iByteIdx = iCol/8; <br/> // get bit index <br/> int iBitIdx = iCol % 8; <br/> // get pixel value @ [iRow, iCol] <br/> BYTE bitshift = pData [iRow * nRowWidth + iByteIdx]> (7-iBitIdx); <br/> byPixel = bitshift & 1; <br/> return byPixel; <br/>}