c/c++语言开发共享C语言实现BMP格式图片转化为灰度

  #include<stdio.h>  #include<malloc.h>  #include<stdlib.h>        #pragma pack(1)  typedef struct tagbitmapfileheader  {      unsigned char bftype[2];//文件格式      unsigned long bfsize;//文件大小      unsigned short bfreserved1;//保留      unsigned short bfreserved2;      unsigned long bfoffbits; //dib数据在文件中的偏移量  }fileheader;  #pragma pack()  /*  位图数据信息结构  */  #pragma pack(1)  typedef struct tagbitmapinfoheader  {      unsigned long bisize;//该结构的大小      long biwidth;//文件宽度      long biheight;//文件高度      unsigned short biplanes;//平面数      unsigned short bibitcount;//颜色位数      unsigned long bicompression;//压缩类型      unsigned long bisizeimage;//dib数据区大小      long bixpixpermeter;      long biypixpermeter;      unsigned long biclrused;//多少颜色索引表      unsigned long biclrimporant;//多少重要颜色  }fileinfo;  #pragma pack()  /*  调色板结构  */  #pragma pack(1)  typedef struct tagrgbquad  {      unsigned char rgbblue; //蓝色分量亮度      unsigned char rgbgreen;//绿色分量亮度      unsigned char rgbred;//红色分量亮度      unsigned char rgbreserved;  }rgbq;  #pragma pack()     int main()  {      file *fp1 = fopen("c:\users\administrator\desktop\data\bmp\image.bmp", "rb+");      if (fp1 == null)      {          printf("打开文件fp1失败");          exit(0);      }         file *fp2 = fopen("c:\users\administrator\desktop\data\bmp\imagegray.bmp", "wb");      if (fp1 == null)      {          printf("打开文件fp2失败");          exit(0);      }         fileheader * fh;      fileinfo * fi;      fh = (fileheader *)malloc(sizeof(fileheader));      fi = (fileinfo *)malloc(sizeof(fileinfo));         //读取位图头结构和信息头      fread(fh, sizeof(fileheader), 1, fp1);      fread(fi, sizeof(fileinfo), 1, fp1);         printf("\\\\\\\\\\原始图片信息\\\\\\\\\\\\\n");      printf("bmp文件头：n");      printf("bfsize:%dn", fh->bfsize);      printf("bfoffbits:%dn", fh->bfoffbits);      printf("\\\\\\\\\\\\\\\\\\\\\\\n");      printf("bmp信息头n");      printf("结构体长度：%d n", fi->bisize);      printf("位图宽度：%d n", fi->biwidth);      printf("位图高度：%d n", fi->biheight);      printf("位图平面数：%d n", fi->biplanes);      printf("颜色位数：%d n", fi->bibitcount);      printf("压缩方式：%d n", fi->bicompression);      printf("实际位图数据占用的字节数：%d n", fi->bisizeimage);      printf("x方向分辨率：%d n", fi->bixpixpermeter);      printf("y方向分辨率：%d n", fi->biypixpermeter);      printf("使用的颜色数：%d n", fi->biclrused);      printf("重要颜色数：%d n", fi->biclrimporant);      printf("\\\\\\\\\\\\\\\\\\\\\\\\n");         //修改信息头      fi->bibitcount = 8;      //fi->bisizeimage = ((fi->biwidth * 3 + 3) / 4) * 4 * fi->biheight;      fi->bisizeimage = fi->biheight*fi->biwidth;      //修改文件头      fh->bfoffbits = sizeof(fileheader) + sizeof(fileinfo) + 256 * sizeof(rgbq);      fh->bfsize = fh->bfoffbits + fi->bisizeimage;         printf("\\\\\\\\\\修改后的图片信息\\\\\\\\\\\\\n");      printf("bmp文件头：n");      printf("bfsize:%dn", fh->bfsize);      printf("bfoffbits:%dn", fh->bfoffbits);      printf("\\\\\\\\\\\\\\\\\\\\\\\n");      printf("bmp信息头n");      printf("结构体长度：%d n", fi->bisize);      printf("位图宽度：%d n", fi->biwidth);      printf("位图高度：%d n", fi->biheight);      printf("位图平面数：%d n", fi->biplanes);      printf("颜色位数：%d n", fi->bibitcount);      printf("压缩方式：%d n", fi->bicompression);      printf("实际位图数据占用的字节数：%d n", fi->bisizeimage);      printf("x方向分辨率：%d n", fi->bixpixpermeter);      printf("y方向分辨率：%d n", fi->biypixpermeter);      printf("使用的颜色数：%d n", fi->biclrused);      printf("重要颜色数：%d n", fi->biclrimporant);      printf("\\\\\\\\\\\\\\\\\\\\\\\\n");         //创建调色板      int i,j,k=0;      rgbq *fq = (rgbq *)malloc(256 * sizeof(rgbq));      for (i = 0; i<256; i++)      {          fq[i].rgbblue = fq[i].rgbgreen = fq[i].rgbred = i;      }      //写入文件头、信息头、调色板      fwrite(fh, sizeof(fileheader), 1, fp2);      fwrite(fi, sizeof(fileinfo), 1, fp2);      fwrite(fq, sizeof(rgbq), 256, fp2);         //将位图信息转为灰度      //存储bmp一行的像素点      //unsigned char imgdata[900][3];      unsigned char imgdata[3000][3];      //将灰度图像存到一维数组中      //unsigned char graydata2[900];      unsigned char imgdata2[3000];      /*      //错误的算法      for (i = 0; i < fi->biheight; i++)      {          for (j = 0; j < (fi->biwidth * 3 + 3) / 4 * 4; j++)          {              for (k = 0; k < 3; k++)              {                  fread(&imgdata[j][k], 1, 1, fp1);              }          }          for (j = 0; j < (fi->biwidth + 3) / 4 * 4; j++)          {              imgdata2[j] = int((float)imgdata[j][0] * 0.114 +                  (float)imgdata[j][1] * 0.587 +                  (float)imgdata[j][2] * 0.299);          }          //将灰度图信息写入          fwrite(imgdata2, j, 1, fp2);      }      */      /*      //正确的算法(1)      for (i = 0; i<fi->biheight; i++)      {          for (j = 0; j<(fi->biwidth + 3) / 4 * 4; j++)          {              for (k = 0; k<3; k++)              fread(&imgdata[j][k], 1, 1, fp1);          }          for (j = 0; j<(fi->biwidth + 3) / 4 * 4; j++)          {              imgdata2[j] = int((float)imgdata[j][0] * 0.114 +                  (float)imgdata[j][1] * 0.587 +                  (float)imgdata[j][2] * 0.299);          }          //将灰度图信息写入          fwrite(imgdata2, j, 1, fp2);      }      */      //正确算法（2）      unsigned char * * bmp_data;      bmp_data = new unsigned char*[fi->biheight]; //声明一个指针数组      unsigned char *data288 = new unsigned char[fi->biheight*fi->biwidth];         for (i = 0; i<fi->biheight; i++)          bmp_data[i] = new unsigned char[(fi->biwidth * 3 + 3) / 4 * 4]; //每个数组元素也是一个指针数组      for (i = 0; i<fi->biheight; i++)          for (j = 0; j<(fi->biwidth * 3 + 3) / 4 * 4; j++)              fread(&bmp_data[i][j], 1, 1, fp1);//每次只读取一个字节，存入数组         for (i = 0; i<fi->biheight; i++)//将24位真彩色转换成灰度图          for (j = 0; j<fi->biwidth; j++){          data288[fi->biwidth*i + j] = ((unsigned char)((float)bmp_data[i][3 * j] * 0.114 + (float)bmp_data[i][3 * j + 1] * 0.587 + (float)bmp_data[i][3 * j + 2] * 0.299));          }         fwrite(data288, fi->bisizeimage, 1, fp2);      free(fh);      free(fi);      free(fq);      fclose(fp1);      fclose(fp2);      printf("successn");      return 0;  }