// ppmdim.c : make frame of picture dim

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

#include "ppmif.c"

// dim target color
int tag[3]={0,0,0};
int t0,t1,t2;
int bwidth=10;
int ctag=-1;
int dimmode=0;   // 0: linear  1: parabola  2:sin

/* the algorithm */
inline int tagadd(imgbyte *p)
{  t0+=p[0]; t1+=p[1]; t2+=p[2]; }

void CalculateTargetColor(imgbyte *data,
			  int w,int h,int sx,int sy,int ex,int ey)
{
    int i,x,y;
    int dw,dh;
    imgbyte *p;
    int ts;
    
    if(ex-sx+1<ctag*2) ctag=(ex-sx+1)/2;
    if(ey-sy+1<ctag*2) ctag=(ey-sy+1)/2;
    t0=t1=t2=ts=0;

    for(i=0;i<ctag;i++)
      {
	  dw=ex-sx+1-i*2;
	  dh=ey-sy+1-i*2;
	  p=data+((sx+i)+(sy+i)*w)*3;
	  for(x=0;x<dw-1;x++,ts++)
	    { tagadd(p); p+=3; }
	  for(y=0;y<dh-1;y++,ts++)
	    { tagadd(p); p+=w*3; }

	  p=data+((sx+i)+(sy+i+1)*w)*3;
	  for(y=0;y<dh-2;y++,ts++)
	    { tagadd(p); p+=w*3; }
	  for(x=0;x<dw;x++,ts++)
	    { tagadd(p); p+=3; }
      }
    t0/=ts;
    t1/=ts;
    t2/=ts;
    if(DEBUG)
      fprintf(stderr,"target color=%d %d %d \n",t0,t1,t2);
}


int Dim(int dist)
{
    double t=((double)dist)/bwidth;
    if(dist>bwidth) return 256;
    switch(dimmode)
      {
	case 1:  // parabola
	  if(t<0.5)
	    return (int)(t*t*2*256);
	  if(t<0.5)
	    return (int)(1-2*(t-1)*(t-1)*256);

	case 2:  //sin
	  return (int)(256*(1-cos(t*3.141592))/2);

	default: // linear
	  return (int)(256*t);
      }
		       
}

inline int ColChange(imgbyte *p,int d1,int d2)
{
    p[0]=(d1*p[0]+d2*t0)>>8;
    p[1]=(d1*p[1]+d2*t1)>>8;
    p[2]=(d1*p[2]+d2*t2)>>8;
}
void DimFrame(imgbyte *data,int w,int h,int sx,int sy,int ex,int ey)
{
    int x,y;
    int i,l;
    imgbyte *p;
    int d1,d2;
    int dw,dh;

    RegulatePos(w,h,&sx,&sy,&ex,&ey);
    if(ex-sx+1<bwidth*2) bwidth=(ex-sx+1)/2;
    if(ey-sy+1<bwidth*2) bwidth=(ey-sy+1)/2;
    t0=tag[0];
    t1=tag[1];
    t2=tag[2];

    if(ctag>0)
      CalculateTargetColor(data,w,h,sx,sy,ex,ey);

    for(i=0;i<bwidth;i++)
      {
	  d1=Dim(i);
	  d2=256-d1;
	  dw=ex-sx+1-i*2;
	  dh=ey-sy+1-i*2;
	  p=data+((sx+i)+(sy+i)*w)*3;
	  for(x=0;x<dw-1;x++)
	    { ColChange(p,d1,d2); p+=3; }
	  for(y=0;y<dh-1;y++)
	    { ColChange(p,d1,d2); p+=w*3; }

	  p=data+((sx+i)+(sy+i+1)*w)*3;
	  for(y=0;y<dh-2;y++)
	    { ColChange(p,d1,d2); p+=w*3; }
	  for(x=0;x<dw;x++)
	    { ColChange(p,d1,d2); p+=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 GetOptionDouble(char **argv,double *is,int st,int limit,int max)
{
    int i;
    double 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],"%lf",&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];
    char *output=NULL;
    FILE *src,*dest;

    for(i=0;i<4;i++) range[i]=-1;
   
    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],"-target")==0)
	     { i+=GetOptionInt(argv,tag,i+1,argc,3); continue; }
	  if(strcmp(argv[i],"-bwidth")==0)
	     { i+=GetOptionInt(argv,&bwidth,i+1,argc,1); continue; }
	  if(strcmp(argv[i],"-calctag")==0)
	     { i+=GetOptionInt(argv,&ctag,i+1,argc,1); continue; }
	  if((strcmp(argv[i],"-output")==0)&&(i+1<argc))
	    { output=argv[i+1]; i++; continue;}
	  if(strcmp(argv[i],"-parabola")==0)
	    { dimmode=1; continue;}
	  if(strcmp(argv[i],"-sin")==0)
	    { dimmode=2; 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]);

    /* do what shall I do */
    DimFrame(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;
}