/************************************************************************/
/*                                                                      */
/*         Program: extract.c                                           */
/*         Purpose: to extract a 3-D volume subset from a larger 3-D    */
/*                  volume                                              */
/*         Input and Output files: 3-D images one character per voxel   */
/*         Programmer: Dale P. Bentz                                    */
/*                     National Institute of Standards and Technology   */
/*                     100 Bureau Drive Stop 8621                       */
/*                     Gaithersburg, MD 20899-8621                      */
/*                     Phone: (301) 975-5865                            */
/*                     Fax: (301) 990-6891                              */
/*                     E-mail: dale.bentz@nist.gov                      */
/*                                                                      */
/*         Date: 2001                                                   */
/*                                                                      */
/***********************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

main(){
	FILE *infile,*outfile;
	char filein[80],fileout[80];
	int iskip,ktrue,jtrue;
	int i,j,k;
	int xsize,ysize,zsize,xcent,ycent,zcent;
	int xred,yred,zred,xlo,xhi,ylo,yhi,zlo,zhi;
	char valin;

/* Get user inputs */
	printf("Enter name of file to read from \n");
	scanf("%s",filein);
	printf("%s\n",filein);
	infile=fopen(filein,"rb");

	printf("Enter name of file to create \n");
	scanf("%s",fileout);
	printf("%s\n",fileout);
	outfile=fopen(fileout,"wb");
      
        printf("It is assumed that in the starting 3-D image file \n");
        printf("x varies the fastest, then y, then z. \n\n");
        printf("Enter center coordinates in starting image for new image subset (x, y, and z) \n");
        scanf("%d %d %d",&xcent,&ycent,&zcent);
        printf("%d %d %d\n",xcent,ycent,zcent);

	printf("Enter size of original image (x y z) \n");
	scanf("%d %d %d",&xsize,&ysize,&zsize);
	printf("%d %d %d\n",xsize,ysize,zsize);

	printf("Enter number of pixels to skip (if any) at beginning of file \n");
        scanf("%d",&iskip);
        printf("%d\n",iskip);

        for(i=0;i<iskip;i++){
             	fscanf(infile,"%c",&valin);
	}

	printf("Enter size of reduced (new) image (x y z)\n");
	scanf("%d %d %d",&xred,&yred,&zred);
	printf("%d %d %d\n",xred,yred,zred);

/* Simply read the original file voxel by voxel and write the appropriate */
/* voxels to the new image file */
	xlo=xcent-(xred/2);
	ylo=ycent-(yred/2);
	zlo=zcent-(zred/2);
	xhi=xlo+xred;
	yhi=ylo+yred;
	zhi=zlo+zred;
	for(k=0;k<zsize;k++){
                ktrue=0;
		if((k>=zlo)&&(k<zhi)){
			ktrue=1;
		}
	for(j=0;j<ysize;j++){
                jtrue=0;
		if((j>=ylo)&&(j<yhi)){
			jtrue=1;
		}
	for(i=0;i<xsize;i++){
		fscanf(infile,"%c",&valin);
		if((ktrue)&&(jtrue)&&(i>=xlo)&&(i<xhi)){
			fprintf(outfile,"%c",valin);
		}
	}
	}
	}
	fclose(infile);
	fclose(outfile);
}