rgb_gray.zip_源码

#include "stdafx.h" #include <stdio.h> #include <string> #include <math.h> #include <windows.h> using namespace std; //将位图转换为256色灰度图 void ToGray(const string& srcFile,const string& desFile) { BITMAPFILEHEADER bmfHeader; BITMAPINFOHEADER bmiHeader; FILE *pFile; if ((pFile = fopen(srcFile.c_str(),"rb")) == NULL) { printf("open bmp file error."); exit(-1); } //读取文件和Bitmap头信息 fseek(pFile,0,SEEK_SET); fread(&bmfHeader,sizeof(BITMAPFILEHEADER),1,pFile); fread(&bmiHeader,sizeof(BITMAPINFOHEADER),1,pFile); //先不支持16位位图 int bitCount = bmiHeader.biBitCount; if (bitCount == 16) { exit(-1); } double byteCount = (double)bitCount / 8; int nClr = 0; if (bitCount < 16) { nClr = bmiHeader.biClrUsed ? bmiHeader.biClrUsed : 1 << bitCount; if (nClr > 256) nClr = 0; } //读取调色板 RGBQUAD *quad = NULL; if (nClr > 0) { quad = new RGBQUAD[nClr]; fread(quad,sizeof(RGBQUAD) * nClr,1,pFile); } int srcW = bmiHeader.biWidth; int srcH = bmiHeader.biHeight; //原图像每一行去除偏移量的字节数 int lineSize = bitCount * srcW >> 3; //偏移量，windows系统要求每个扫描行按四字节对齐 int alignBytes = (((bmiHeader.biWidth * bitCount + 31) & ~31) >> 3) - ((bmiHeader.biWidth * bitCount) >> 3); //原图像缓存 int srcBufSize = lineSize * srcH; BYTE* srcBuf = new BYTE[srcBufSize]; int i,j; //读取文件中数据 for (i = 0; i < srcH; i++) { fread(&srcBuf[lineSize * i],lineSize,1,pFile); fseek(pFile,alignBytes,SEEK_CUR); } //256色位图调色板 RGBQUAD *quadDes = NULL; quadDes = new RGBQUAD[256]; for (i = 0; i < 256; i++) { //灰度图的RGB值相等 quadDes[i].rgbBlue = quadDes[i].rgbGreen = quadDes[i].rgbRed = i; } //灰度图每个像素采用8位表示 int desBufSize = (((srcW * 8 + 31) & ~31) >> 3) * srcH; BYTE *desBuf = new BYTE[desBufSize]; //每个扫描行占用字节数 int desLineSize = ((srcW * 8 + 31) >> 5) * 4; for (i = 0; i < srcH; i++) { for (j = 0; j < srcW; j++) { //从调色板中读取RGB值 if (nClr > 0) { unsigned int pos = srcBuf[i * lineSize + int(j * byteCount)]; desBuf[i * desLineSize + j] = 0.3 * quad[pos].rgbRed + 0.59 * quad[pos].rgbGreen + 0.11 * quad[pos].rgbBlue; } else desBuf[i * desLineSize + j] = 0.3 * srcBuf[i * lineSize + int(j * byteCount)] + 0.59 * srcBuf[i * lineSize + int(j * byteCount) + 1] + 0.11 * srcBuf[i * lineSize + int(j * byteCount) + 2]; } } //创建目标文件 HFILE hfile = _lcreat(desFile.c_str(),0); //文件头信息 BITMAPFILEHEADER nbmfHeader; nbmfHeader.bfType = 0x4D42; nbmfHeader.bfSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + 256 * sizeof(RGBQUAD) + srcW * srcH; nbmfHeader.bfReserved1 = 0; nbmfHeader.bfReserved2 = 0; nbmfHeader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + 256 * sizeof(RGBQUAD); //Bitmap头信息 BITMAPINFOHEADER bmi; bmi.biSize=sizeof(BITMAPINFOHEADER); bmi.biWidth=srcW; bmi.biHeight=srcH; bmi.biPlanes=1; bmi.biBitCount=8; bmi.biCompression=BI_RGB; bmi.biSizeImage=0; bmi.biXPelsPerMeter=0; bmi.biYPelsPerMeter=0; bmi.biClrUsed= 256; bmi.biClrImportant=0; //写入文件头信息 _lwrite(hfile,(LPCSTR)&nbmfHeader,sizeof(BITMAPFILEHEADER)); //写入Bitmap头信息 _lwrite(hfile,(LPCSTR)&bmi,sizeof(BITMAPINFOHEADER)); if (quadDes) { _lwrite(hfile,(LPCSTR)quadDes,sizeof(RGBQUAD) * 256); } //写入图像数据 _lwrite(hfile,(LPCSTR)desBuf,desBufSize); _lclose(hfile); if (quad) { delete[] quad; quad = NULL; } if (quadDes) { delete[] quadDes; quadDes = NULL; } } int main(int argc, char* argv[]) { string srcFile("g://hangmu001.bmp"); //srcFile.erase(srcFile.length()-3,4); string desFile(srcFile + "_gray.bmp"); ToGray(srcFile,desFile); system("pause"); return 0; }