bmpedge.c

This is code tutorial for image processing include:histogram,sketon....

read_bmp_image(file_name, array)
   char  *file_name;
   short **array;
{
   FILE   *fp;
   int    i, j;
   int    negative = 0,
          pad      = 0,
          place    = 0;
   long   colors   = 0,
          height   = 0,
          position = 0,
          width    = 0;
   struct bmpfileheader file_header;
   struct bitmapheader  bmheader;
   struct ctstruct rgb[GRAY_LEVELS+1];
   unsigned char uc;

   read_bmp_file_header(file_name, &file_header);
   read_bm_header(file_name, &bmheader);
   if(bmheader.bitsperpixel != 8){
      printf("\nCannot read image when bits per"
      "pixel is not 8");
      exit(1);
   }

   if(bmheader.colorsused == 0)
      colors = GRAY_LEVELS + 1;
   else
      colors = bmheader.colorsused;
   read_color_table(file_name, &rgb, colors);

   fp = fopen(file_name, "rb");
   fseek(fp, file_header.bitmapoffset, SEEK_SET);

   width = bmheader.width;
   if(bmheader.height < 0){
      height   = bmheader.height * (-1);
      negative = 1;
   }
   else
      height = bmheader.height;

   pad = calculate_pad(width);

   for(i=0; i<height; i++){
      for(j=0; j<width; j++){
         place = fgetc(fp);
         uc = (place & 0xff);
         place = uc;
         array[i][j] = rgb[place].blue;
      }  /* ends loop over j */
      if(pad != 0){
         position = fseek(fp, pad, SEEK_CUR);
      }  /* ends if pad 1= 0 */
   }  /* ends loop over i */

   if(negative = 0)
      flip_image_array(array, height, width);

}  /* ends read_bmp_image */






   /*********************************************
   *
   *   create_allocate_bmp_file(...
   *
   *   The calling routine must set the 
   *   height and width.  This routine will set
   *   everything else.
   *
   **********************************************/

create_allocate_bmp_file(file_name,
                         file_header,
                         bmheader)
   char  *file_name;
   struct bmpfileheader *file_header;
   struct bitmapheader  *bmheader;
{
   char buffer[100];
   int  i, pad = 0;
   FILE *fp;

   pad = calculate_pad(bmheader->width);

   bmheader->size         =  40;
   bmheader->planes       =   1;
   bmheader->bitsperpixel =   8;
   bmheader->compression  =   0;
   bmheader->sizeofbitmap = bmheader->height * 
                            (bmheader->width + pad);
   bmheader->horzres      = 300;
   bmheader->vertres      = 300;
   bmheader->colorsused   = 256;
   bmheader->colorsimp    = 256;

   file_header->filetype     = 0x4D42;
   file_header->reserved1    =  0;
   file_header->reserved2    =  0;
   file_header->bitmapoffset = 14 + 
                               bmheader->size +
                               bmheader->colorsused*4;
   file_header->filesize     = file_header->bitmapoffset +
                               bmheader->sizeofbitmap;

   if((fp = fopen(file_name, "wb")) == NULL){
      printf("\nERROR Could not create file %s",
             file_name);
      exit(2);
   }

      /*********************************************
      *
      *   Write the 14-byte bmp file header.
      *
      *********************************************/

   insert_ushort_into_buffer(buffer, 0, file_header->filetype);
   fwrite(buffer, 1, 2, fp);

   insert_ulong_into_buffer(buffer, 0, file_header->filesize);
   fwrite(buffer, 1, 4, fp);

   insert_short_into_buffer(buffer, 0, file_header->reserved1);
   fwrite(buffer, 1, 2, fp);

   insert_short_into_buffer(buffer, 0, file_header->reserved2);
   fwrite(buffer, 1, 2, fp);

   insert_ulong_into_buffer(buffer, 0, file_header->bitmapoffset);
   fwrite(buffer, 1, 4, fp);


      /*********************************************
      *
      *   Write the 40-byte bit map header.
      *
      *********************************************/

   insert_ulong_into_buffer(buffer, 0, bmheader->size);
   fwrite(buffer, 1, 4, fp);

   insert_long_into_buffer(buffer, 0, bmheader->width);
   fwrite(buffer, 1, 4, fp);

   insert_long_into_buffer(buffer, 0, bmheader->height);
   fwrite(buffer, 1, 4, fp);

   insert_ushort_into_buffer(buffer, 0, bmheader->planes);
   fwrite(buffer, 1, 2, fp);

   insert_ushort_into_buffer(buffer, 0, bmheader->bitsperpixel);
   fwrite(buffer, 1, 2, fp);

   insert_ulong_into_buffer(buffer, 0, bmheader->compression);
   fwrite(buffer, 1, 4, fp);

   insert_ulong_into_buffer(buffer, 0, bmheader->sizeofbitmap);
   fwrite(buffer, 1, 4, fp);

   insert_ulong_into_buffer(buffer, 0, bmheader->horzres);
   fwrite(buffer, 1, 4, fp);

   insert_ulong_into_buffer(buffer, 0, bmheader->vertres);
   fwrite(buffer, 1, 4, fp);

   insert_ulong_into_buffer(buffer, 0, bmheader->colorsused);
   fwrite(buffer, 1, 4, fp);

   insert_ulong_into_buffer(buffer, 0, bmheader->colorsimp);
   fwrite(buffer, 1, 4, fp);

      /*********************************************
      *
      *   Write a blank color table.
      *   It has 256 entries (number of colors)
      *   that are each 4 bytes.
      *
      *********************************************/

   buffer[0] = 0x00;

   for(i=0; i<(256*4); i++)
      fwrite(buffer, 1, 1, fp);

      /*********************************************
      *
      *   Write a zero image.  
      *
      *********************************************/

   buffer[0] = 0x00;

   for(i=0; i<bmheader->sizeofbitmap; i++)
      fwrite(buffer, 1, 1, fp);

   fclose(fp);

}  /* ends create_allocate_bmp_file */






create_bmp_file_if_needed(in_name, out_name, out_image)
   char in_name[], out_name[];
   short **out_image;
{
   int    length, width;
   struct bmpfileheader file_header;
   struct bitmapheader  bmheader;

   if(does_not_exist(out_name)){
      printf("\n\n output file does not exist %s",
               out_name);
      read_bm_header(in_name, &bmheader);
      create_allocate_bmp_file(out_name, &file_header, &bmheader);
      printf("\nBFIN> Created %s", out_name);
   }  /* ends if does_not_exist */
}  /* ends bcreate_file_if_needed */




write_bmp_image(file_name, array)
   char   *file_name;
   short  **array;
{
   char   *buffer, c;
   FILE   *image_file;
   int    pad = 0,
          position;
   int    bytes, i, j;
   long   height = 0, width = 0;
   struct bitmapheader  bmheader;
   struct bmpfileheader file_header;
   struct ctstruct rgb[GRAY_LEVELS+1];
   union  short_char_union scu;

   read_bmp_file_header(file_name, &file_header);
   read_bm_header(file_name, &bmheader);

   height = bmheader.height;
   width  = bmheader.width;
   if(height < 0) height = height*(-1);

   buffer = (char  *) malloc(width * sizeof(char ));
   for(i=0; i<width; i++)
      buffer[i] = '\0';

   image_file = fopen(file_name, "rb+");

      /****************************************
      *
      *   Write the color table first.
      *
      ****************************************/

   position   = fseek(image_file, 54, SEEK_SET);
   for(i=0; i<GRAY_LEVELS+1; i++){
      rgb[i].blue  = i;
      rgb[i].green = i;
      rgb[i].red   = i;
   }  /* ends loop over i */

   for(i=0; i<bmheader.colorsused; i++){
      buffer[0] = rgb[i].blue;
      fwrite(buffer , 1, 1, image_file);
      buffer[0] = rgb[i].green;
      fwrite(buffer , 1, 1, image_file);
      buffer[0] = rgb[i].red;
      fwrite(buffer , 1, 1, image_file);
      buffer[0] = 0x00;
      fwrite(buffer , 1, 1, image_file);
   }  /* ends loop over i */

   position   = fseek(image_file,
                      file_header.bitmapoffset, 
                      SEEK_SET);

   pad = calculate_pad(width);

   for(i=0; i<height; i++){
      for(j=0; j<width; j++){

         if(bmheader.bitsperpixel == 8){
            scu.s_num = 0;
            if(bmheader.height > 0)
               scu.s_num = array[height-1-i][j];
            else
               scu.s_num = array[i][j];
            buffer[j] = scu.s_alpha[0];
         }  /* ends if bits_per_pixel == 8 */
         else{
            printf("\nERROR bitsperpixel is not 8");
            exit(1);
         }
      }  /* ends loop over j */

      bytes = fwrite(buffer, 1, width, image_file);

      if(pad != 0){
         for(j=0; j<pad; j++)
            buffer[j] = 0x00;
         fwrite(buffer, 1, pad, image_file);
      }  /* ends if pad != 0 */

   }  /* ends loop over i */

   fclose(image_file);

   free(buffer);

}  /* ends write_bmp_image */




int calculate_pad(width)
   long width;
{
   int pad = 0;
   pad = ( (width%4) == 0) ? 0 : (4-(width%4));
   return(pad);
}  /* ends calculate_pad */