writrast.c

NIST Handwriting OCR Testbed

/*
# proc: writeihdrfile - writes the contents of an IHead structure and an
# proc:                 image memory to the specified file.
*/

/************************************************************/
/*         File Name: WriteRaster.c                         */
/*         Package:   Image Read Routines                   */
/*                                                          */
/*         Contents:  writeihdrfile()                       */
/************************************************************/
#include <stdio.h>
#include <ihead.h>

/************************************************************/
/*         Routine:   Writeihdrfile()                       */
/*         Author:    Michael D. Garris                     */
/*         Date:      4/26/89                               */
/*         Modifications:                                   */
/*           9/20/90   (Stan Janet) check return codes      */
/*           2/20/91   (MDG) compression capability         */
/*           12/94     (Patrick Grother)                    */
/*      Allocate 4 times the original image for the rare    */
/*      case (noisy image) where the compressed result has  */
/*      grown in size to be larger than the original image  */
/************************************************************/
/************************************************************/
/* Writeihdrfile() writes a ihead structure and correspon-  */
/* ding image data to the specified file.                   */
/************************************************************/
void writeihdrfile(file,head,data)
char *file;
IHEAD *head;
unsigned char *data;
{
   FILE *fp;
   int width,height,depth,code,filesize,n, compbytes;
   unsigned char *compdata;

   /* reopen the image file for writing */
   fp = fopen(file,"wb");
   if (fp == NULL)
      syserr("writeihdrfile","fopen",file);

   n = sscanf(head->width,"%d",&width);
   if (n != 1)
      fatalerr("writeihdrfile","sscanf failed on width field",NULL);
   n = sscanf(head->height,"%d",&height);
   if (n != 1)
      fatalerr("writeihdrfile","sscanf failed on height field",NULL);
   n = sscanf(head->depth,"%d",&depth);
   if (n != 1)
      fatalerr("writeihdrfile","sscanf failed on depth field",NULL);
   n = sscanf(head->compress, "%d", &code);
   if (n != 1)
      fatalerr("writeihdrfile","sscanf failed on compression code field",NULL);

   filesize = SizeFromDepth(width,height,depth);
   if ( code == CCITT_G4 )  /* G4 compression breaks for noisy images since */
      filesize *= 4;        /* the result is larger than the original. The  */
                            /* buffer is exceeded and a segmentation fault  */
                            /* occurs. The factor 4 is empirically found    */
                            /* to be sufficient.                            */

   if(code == UNCOMP){
      sprintf(head->complen, "%d", 0);
      writeihdr(fp,head);
      n = fwrite(data,1,filesize,fp);
      if (n != filesize)
         syserr("writeihdrfile", "fwrite", file);
   }
   else{
      malloc_uchar(&compdata, filesize, "writeihdrfile : compdata");
      switch(code){
      case CCITT_G4:
         if(depth != 1)
            fatalerr("writeihdrfile",
                     "G4 compression requires a binary image.", NULL);
         grp4comp(data, filesize, width, height, compdata, &compbytes);
         break;
      default:
         fatalerr("writeihdrfile","Unknown compression",NULL);
         break;
      }
      sprintf(head->complen, "%d", compbytes);
      writeihdr(fp,head);
      n = fwrite(compdata,1,compbytes,fp);
      if (n != compbytes)
         syserr("writeihdrfile", "fwrite", file);
      free(compdata);
   }

   /* closes the new file */
   (void) fclose(fp);
}