/* ppm dizer                       by kumagai masaaki*/
/* as example of xv algorithm extension              */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "ppmif.c"

const int dtab[4][4]={ 
{ 0x00, 0x80, 0x20, 0xb0 },
{ 0xc0, 0x40, 0xd0, 0x70 },
{ 0x30, 0xa0, 0x10, 0x90 },
{ 0xe0, 0x60, 0xf0, 0x50 },
} ;
/* the algorithm */
void Diz(imgbyte *data,int w,int h,int sx,int sy,int ex,int ey)
{
    int x,y,ry,y2;
    int r=0,g=0,b=0;
    imgbyte *p;
    RegulatePos(w,h,&sx,&sy,&ex,&ey);
    for(y=sy;y<ey+4;y+=4)
      {
	  ry=ey-y+1;
	  if(ry>4) ry=4;
	  for(x=sx;x<=ex;x++)
	    {
		p=data+(w*y+x)*3;
		for(y2=0;y2<ry;y2++)
		  {
		      /* r */
		      r+=p[0];
		      if(r>dtab[x%4][(y+y2)%4])
			{
			    p[0]=0xff;
			    r-=0xff;
			}
		      else p[0]=0;
		      /* g */
		      g+=p[1];
		      if(g>dtab[x%4][(y+y2)%4])
			{
			    p[1]=0xff;
			    g-=0xff;
			}
		      else p[1]=0;
		      /* r */
		      b+=p[2];
		      if(b>dtab[x%4][(y+y2)%4])
			{
			    p[2]=0xff;
			    b-=0xff;
			}
		      else p[2]=0;
		      p+=w*3;
		  }
	    }
      }
}

int GetOptionInt(char **argv,int *is,int st,int limit,int max)
{
    int i;
    int ii;
    if(st+max<limit) limit=st+max;
    for(i=st;i<limit;i++)
      {
	  if(argv[i]==NULL) return i-st;
	  if(sscanf(argv[i],"%d",&ii)==0)
	    return i-st;
	  is[i-st]=ii;
      }
    return i-st;
}

int IsOption(char *s)
{ return (s[0]=='-'); };

int main(int argc,char **argv)
{
    int w,h,i,max;
    imgbyte *data;
    int range[4];
    int rstep[100],gstep[100],bstep[100];
    char *output=NULL;
    FILE *src,*dest;
    int bwidth=4;

    for(i=0;i<4;i++) range[i]=-1;
    for(i=0;i<100;i++) rstep[i]=gstep[i]=bstep[i]=0;
    
    rstep[0]=gstep[0]=bstep[0]=255;

    for(i=1;i<argc;i++)
      {
	  if(!IsOption(argv[i]))
	    break;
	  
	  if(strcmp(argv[i],"-range")==0)
	     { i+=GetOptionInt(argv,range,i+1,argc,4); continue; }

	  if((strcmp(argv[i],"-output")==0)&&(i+1<argc))
	    { output=argv[i+1]; i++; continue;}
	  if(strcmp(argv[i],"-debug")==0)
	    { DEBUG=1; continue; }
      }
    /* check FILE */
    if(i<argc)
      {
	  if(DEBUG)
	    fprintf(stderr,"read from '%s'\n",argv[i]);
	  src=fopen(argv[i],"rb");
	  if(src==NULL)
	    {
		fprintf(stderr,"cannot open source file '%s'\n",argv[i]);
		return 1;
	    }
      }
    else src=stdin;
    if(output)
      {
	  if(DEBUG)
	    fprintf(stderr,"write out to '%s'\n",output);
	  dest=fopen(output,"wb");
	  if(dest==NULL)
	    {
		fprintf(stderr,"cannot open destination file '%s'\n",output);
		return 1;
	    }
      }
    else dest=stdout;

    /* read data */
    data=LoadPPM(src,&w,&h,&max);
    if(data==NULL)
      {
	  fprintf(stderr,"cannot load source \n");
	  return 1;
      }

    if(range[0]<0) range[0]=0;
    if(range[1]<0) range[1]=0;
    if(range[2]<0) range[2]=w-1;
    if(range[3]<0) range[3]=h-1;
    if(DEBUG)
      fprintf(stderr,"range: %d,%d-%d,%d",range[0],range[1],range[2],range[3]);

    Diz(data,w,h, range[0],range[1],range[2],range[3]);

    /* write out output */
    SavePPM(dest,data,max,  w,h, 0,0,w-1,h-1);
    return 0;
}